You are cordially invited to attend a special meeting (together with any adjournment, postponement or other delay thereof, the “Piedmont special meeting”) of stockholders of Piedmont Lithium Inc., a Delaware corporation (“Piedmont”). You may attend the Piedmont special meeting via a live interactive webcast on [ ], 2025, at [ ] [A.M.] [P.M.], Eastern Time, by visiting the following website: [ ]. Holders of Piedmont CDIs (as defined below) are entitled to receive notice of, and attend as guests (but not vote at), the Piedmont special meeting and may instruct CHESS Depositary Nominees Pty Ltd. (the “CDI Depositary”) to vote the shares underlying their Piedmont CDIs. See “Notice of Special Meeting of Piedmont Stockholders to be Held on [ ], 2025” for additional information about attending and participating in the meeting. Whether or not you plan to attend, please vote your shares as promptly as possible.

On November 18, 2024, Piedmont, Sayona Mining Limited, an Australian public company limited by shares (“Sayona”), and Shock MergeCo Inc., a Delaware corporation and a wholly owned subsidiary of Sayona (“Merger Sub”), entered into an Agreement and Plan of Merger (as subsequently amended on April 22, 2025 and as it may be further amended from time to time, the “merger agreement”) that provides for the merger of Piedmont with Sayona. On the terms and subject to the conditions set forth in the merger agreement, Merger Sub will merge with and into Piedmont (the “merger” or the “transaction”) with Piedmont surviving the merger as a wholly owned subsidiary of Sayona, and, as a result of the merger, the separate existence of Merger Sub shall cease.

Upon the successful completion of the transaction, each share of Piedmont common stock, par value $0.0001 per share (“Piedmont common stock”), issued and outstanding immediately prior to the effective time of the merger, including any share in respect of which a Piedmont CHESS depository interest (“Piedmont CDI”) has been issued (excluding any excluded shares (as defined below), or converted shares (as defined below)) (which shares of Piedmont common stock are referred to as the “eligible shares”) will be converted as follows: (1) each Piedmont CDI representing 1/100th of an eligible share of Piedmont common stock issued and outstanding as of a record date prior to the effective time of the merger to be established pursuant to the settlement rules of ASX Limited ABN 98 008 624 691 (the “ASX”) will be converted into the right to receive 5.27 ordinary shares of Sayona (“Sayona ordinary shares”) or 0.035133 Sayona ordinary shares if, prior to the completion of the transaction, Sayona effects a consolidation of Sayona’s equity securities whereby 150 Sayona ordinary shares will be converted into one Sayona ordinary share (the “Sayona share consolidation”) (the “Sayona ordinary share consideration”); and (2) each share of Piedmont common stock issued and outstanding immediately prior to the effective time of the merger and not represented by a Piedmont CDI will be converted into the right to receive 0.35133 American depositary shares of Sayona (“Sayona ADSs”), representing together 527 Sayona ordinary shares or 3.5133 Sayona ordinary shares if, prior to the completion of the transaction, Sayona effects the Sayona share consolidation (the “Sayona ADS consideration” and together with the Sayona ordinary share consideration, the “merger consideration”). If you receive merger consideration and would otherwise be entitled to receive a fractional share of Sayona ordinary shares or Sayona ADSs, such fractional shares of Sayona ordinary shares or Sayona ADSs will be rounded up to the nearest whole share. Any such fractional shares issuable to the same Piedmont stockholder will be aggregated first and prior to eliminating fractional shares (with respect to shares of Piedmont common stock held through the Depository Trust Company (“DTC”), in accordance with DTC’s procedures). The Sayona ADSs to be issued in connection with the transaction are expected to be listed on the Nasdaq Stock Market LLC (the “Nasdaq”) and trade under the symbol “ELVR,” unless the Sayona shareholders do not approve the change of Sayona’s name to Elevra Lithium Limited, in which case Sayona expects to reserve an alternate symbol. The Sayona ordinary shares to be issued in the merger are expected to be listed for trading on the ASX under the trading symbol “ELV”, unless the Sayona shareholders do not approve the change of Sayona’s name to Elevra Lithium Limited, in which case the Sayona ordinary shares are expected to be listed for trading on the ASX under the current trading symbol “SYA”. Sayona has submitted to, and discussed with, the Nasdaq its initial listing application with respect to the Sayona ADSs and expects to know the Nasdaq’s determination regarding such application prior to the Piedmont special meeting and the Sayona extraordinary general meeting. Immediately after the effective time of the merger, the pre-merger Sayona shareholders, on the one hand, and the pre-merger holders of eligible shares of Piedmont common stock and Piedmont CDIs (holders of Piedmont CDIs, collectively with holders of Piedmont common stock, the

“Piedmont stockholders,” unless the context otherwise requires), on the other hand, will each own collectively approximately 50% of the ordinary shares of Sayona on a fully diluted basis (including the Sayona ordinary shares represented by the Sayona ADSs). Sayona ordinary shares are traded on the ASX under the symbol “SYA” and, as a secondary listing, on the OTCQB Venture Market in the United States under the symbol “SYAXF.” Piedmont common stock is traded on the Nasdaq under the symbol “PLL.” Piedmont CDIs are traded on the ASX under the symbol “PLL.” We encourage you to obtain current quotes for Sayona ordinary shares, Piedmont common stock, and Piedmont CDIs.

The market value of the merger consideration to Piedmont stockholders will fluctuate with the market price of Sayona ordinary shares and will not be known at the time that Piedmont stockholders vote on the transaction. Based on Sayona’s closing share price and the spot Australian Dollar-U.S. Dollar exchange rate, in each case, on November 18, 2024, the last trading day before the public announcement of the execution of the merger agreement, the implied value of the merger consideration to Piedmont stockholders was approximately $13.03 per share of Piedmont common stock.

At the Piedmont special meeting, Piedmont stockholders will be asked to consider and vote on (1) a proposal to adopt and approve the merger agreement (the “Piedmont merger proposal”), (2) a proposal to approve, on a non-binding advisory basis, the compensation that will or may become payable by Piedmont to its named executive officers in connection with the merger of Merger Sub with and into Piedmont (the “advisory compensation proposal”) and (3) any proposal to postpone or adjourn the Piedmont special meeting, from time to time, to a later date or dates, if necessary or appropriate, including to solicit additional proxies if there are insufficient votes to adopt and approve the merger agreement at the time of the Piedmont special meeting (the “adjournment proposal,” and together with the Piedmont merger proposal and the advisory compensation proposal, the “Proposals”). Piedmont’s board of directors unanimously recommends that Piedmont stockholders vote “FOR” the Piedmont merger proposal, “FOR” the advisory compensation proposal and “FOR” the adjournment proposal.

We cannot complete the transaction unless, among other things, the Piedmont merger proposal is approved by Piedmont stockholders. Your vote on these matters is very important, regardless of the number of shares of Piedmont common stock or Piedmont CDIs you own. Whether or not you plan to attend the Piedmont special meeting, please promptly mark, sign and date the accompanying proxy card or voting instruction card and return it in the enclosed postage-paid envelope, call the toll-free telephone number or use the Internet as described in the instructions included with your proxy card in order to authorize the individuals named on your proxy card to vote your shares at the Piedmont special meeting.

This proxy statement/prospectus provides you with important information about the Piedmont special meeting, the transaction, and each of the Proposals to be considered at the Piedmont special meeting. We encourage you to read the entire document, including the annexes and documents incorporated by reference therein, carefully, in particular the “Risk Factors” section beginning on page 32 for a discussion of risks that you should consider in evaluating the transaction.

Neither the U.S. Securities and Exchange Commission nor any state securities commission has approved or disapproved of the transaction, the adoption and approval of the merger agreement or any of the other transactions described in this proxy statement/prospectus or determined if this proxy statement/prospectus is accurate or complete. Any representation to the contrary is a criminal offense.

This proxy statement/prospectus is dated [   ], 2025 and is first being mailed to Piedmont stockholders on or about [   ], 2025.

Piedmont files annual, quarterly and other reports, proxy statements and other information with the U.S. Securities and Exchange Commission (the “SEC”). This proxy statement/prospectus incorporates by reference important business and financial information about Piedmont from documents that are not included in or delivered with this proxy statement/prospectus. For a listing of the documents incorporated by reference into this proxy statement/prospectus, see the section of this proxy statement/prospectus entitled “Where You Can Find Additional Information” beginning on page 296. You can obtain copies of the documents incorporated by reference into this proxy statement/prospectus, without charge, from the SEC’s website at http://www.sec.gov.

You may also request copies of such documents incorporated by reference into this proxy statement/prospectus (excluding all exhibits, unless an exhibit has specifically been incorporated by reference into this proxy statement/prospectus), without charge, by requesting them in writing or by telephone from Piedmont at the following address and telephone number:

In addition, if you have questions about the transaction or the Piedmont special meeting, need additional copies of this document or need to obtain proxy cards or other information related to the proxy solicitation, you may contact Sodali & Co., Piedmont’s proxy solicitor, at the following address and telephone numbers:

You will not be charged for any of the documents you request. If you would like to request documents, please do so by [  ], 2025 (which is five business days before the date of the Piedmont special meeting) in order to receive them before the Piedmont special meeting.

This proxy statement/prospectus, which forms part of a registration statement on Form F-4 (File No. 333-286715) filed with the SEC by Sayona, constitutes a prospectus of Sayona under Section 5 of the U.S. Securities Act of 1933, as amended (the “U.S. Securities Act”) with respect to Sayona ordinary shares (including Sayona ordinary shares represented by the Sayona ADSs) to be issued to Piedmont stockholders pursuant to the merger agreement.

This proxy statement/prospectus also constitutes a notice of meeting and a proxy statement of Piedmont under Section 14(a) of the U.S. Securities Exchange Act of 1934, as amended (the “U.S. Exchange Act”), with respect to the Piedmont special meeting, at which Piedmont stockholders will be asked to consider and vote on, among other matters, the Piedmont merger proposal.

No one has been authorized to provide you with information that is different from that contained in, or incorporated by reference into, this proxy statement/prospectus. This proxy statement/prospectus is dated [  ], 2025. The information contained in this proxy statement/prospectus is accurate only as of that date or, in the case of information in a document incorporated by reference, as of the date of such document, unless the information specifically indicates that another date applies. Neither the mailing of this proxy statement/prospectus to Piedmont stockholders nor the issuance of Sayona ADSs or Sayona ordinary shares pursuant to the merger agreement will create any implication to the contrary.

This proxy statement/prospectus has been prepared without taking into account the specific objectives, financial situation or needs of individual shareholders or prospective investors. Before making an investment decision, shareholders or prospective investors should consider the appropriateness of the information having regard to their own objectives, financial situation and needs and seek appropriate advice, including financial, legal and taxation advice appropriate to their jurisdiction and circumstances. Neither Sayona nor Piedmont is licensed to provide financial product advice in respect of its securities.

This proxy statement/prospectus does not constitute an offer to sell, or a solicitation of an offer to buy, any securities, or the solicitation of a proxy, in any jurisdiction in which it is unlawful to make any such offer or solicitation in such jurisdiction.

The information concerning Sayona contained in this proxy statement/prospectus has been provided by Sayona, and information concerning Piedmont contained in, or incorporated by reference into, this proxy statement/prospectus has been provided by Piedmont.

Unless otherwise specified, currency amounts referenced in this proxy statement/prospectus are in U.S. dollars and all dates and times referenced in this proxy statement/prospectus are Eastern Time in the United States.

This proxy statement/prospectus contains or is accompanied by:

Unless indicated otherwise, financial data presented in this proxy statement/prospectus has been taken from the Sayona annual financial statements and the Sayona interim financial statements included in this proxy statement/prospectus and from the Piedmont annual financial statements and the Piedmont interim financial statements incorporated by reference into this proxy statement/prospectus.

This proxy statement/prospectus also contains the unaudited pro forma combined financial information of Sayona as of December 31, 2024, for the six month period ended December 31, 2024 and for the year ended June 30, 2024, after giving effect to the completion of the transaction, referred to in this proxy statement/prospectus as “unaudited pro forma combined financial information.” See the section of this proxy statement/prospectus entitled “Sayona Unaudited Pro Forma Combined Financial Information” beginning on page 181. For the purposes of the unaudited pro forma combined financial information, Piedmont financial information is converted from U.S. GAAP to IFRS accounting standards. The financial information set forth in this proxy statement/prospectus has been rounded for ease of presentation. Accordingly, in certain cases, the sum of the numbers in a column in a table may not conform to the total figure given for that column.

For additional information on the presentation of financial information of Sayona and Piedmont in this proxy statement/prospectus, see the Sayona annual financial statements beginning on page F-2 of this proxy statement/prospectus, the Sayona interim financial statements beginning on page F-47, and the Piedmont annual financial statements and the Piedmont interim financial statements incorporated by reference into this proxy statement/prospectus.

Notice is hereby given that Piedmont Lithium Inc., a Delaware corporation (“Piedmont”), will hold a special meeting of its stockholders (together with any adjournment, postponement or other delay thereof, the “Piedmont special meeting”), at [  ] [A.M.] [P.M.], Eastern Time, on [  ], 2025, for the purpose of considering and voting on the following proposals:

Piedmont will transact no other business at the Piedmont special meeting, except such business as may properly be brought before the Piedmont special meeting or any adjournment or postponement thereof.

The proxy statement/prospectus to which this notice is attached includes a summary of the merger agreement, and a complete copy of the merger agreement is attached as Annex A to the proxy statement/prospectus. Please read the proxy statement/prospectus and its annexes, including the merger agreement, carefully and in their entirety, as they contain important information.

You may attend the Piedmont special meeting via a live interactive webcast on [  ], 2025, at [  ] [A.M.] [P.M.], Eastern Time, by visiting the following website: [  ]. Online check-in will begin a few minutes prior to the Piedmont special meeting, and you should allow ample time for the check-in procedures. You will need the control number printed on your proxy card or voting instruction form that accompanied your proxy materials to participate in the Piedmont special meeting (including voting your shares). If you lose your control number, you may join the Piedmont special meeting as a guest, but you will not be able to vote. Piedmont believes that a virtual meeting provides expanded access, improved communication and cost savings for its stockholders.

Holders of record of shares of the common stock, par value $0.0001 per share of Piedmont (the “Piedmont common stock”) as of the close of business on [  ], 2025 (the “record date”), are entitled to notice of and to vote at the Piedmont special meeting. In addition, holders of Piedmont’s CHESS depository interest (the “Piedmont CDI”) as of the record date are entitled to notice of and to attend as guests (but not vote at) the Piedmont special meeting, and may instruct the CHESS Depositary Nominees Pty Ltd., as CDI depositary, to vote the shares underlying their Piedmont CDIs by following the instructions on the Piedmont CDI voting instruction form.

Piedmont’s board of directors, after considering the various factors described in the section of this proxy statement/prospectus entitled “The Merger—Recommendation of the Piedmont Board; Piedmont’s Reasons for the Merger,” unanimously: (1) determined that the merger agreement and the transactions contemplated thereby, including the merger, are in the best interests of Piedmont and Piedmont stockholders; (2) approved and declared advisable the merger agreement and the transactions contemplated thereby, including the merger; and (3) resolved, subject to the provisions of the merger agreement, to recommend that Piedmont stockholders vote in favor of adoption and approval of the merger agreement.

Piedmont’s board of directors unanimously recommends that Piedmont stockholders vote “FOR” the Piedmont merger proposal, “FOR” the advisory compensation proposal and “FOR” the adjournment proposal.

Your vote is very important, regardless of the number of shares of Piedmont common stock that you own. The merger cannot be completed without approval of the Piedmont merger proposal. Assuming a quorum is present, the approval of the Piedmont merger proposal requires the affirmative vote of a majority of the outstanding shares of Piedmont common stock entitled to vote on the Piedmont merger proposal.

Even if you plan to attend the Piedmont special meeting, please sign, date and return, as promptly as possible, the enclosed proxy card (a prepaid reply envelope is provided for your convenience) or grant your proxy electronically over the Internet or by telephone (using the instructions found on the proxy card). If you attend the Piedmont special meeting and vote at the Piedmont special meeting, your vote will revoke any proxy that you have previously submitted. If you fail to return your proxy or to attend the Piedmont special meeting, your shares will not be counted for purposes of determining whether a quorum is present at the Piedmont special meeting or be voted at the meeting, and, if a quorum is present, that will have the same effect as voting “AGAINST” the Piedmont merger proposal.

If your shares are held through a bank, broker or other nominee, you are considered the “beneficial owner” of shares held in “street name.” If you hold your shares in “street name,” you will receive instructions from your bank, broker or other nominee that you must follow in order to submit your voting instructions and have your shares counted at the Piedmont special meeting. Your bank, broker or other nominee cannot vote on any of the Proposals to be considered at the Piedmont special meeting without your instructions. Without your instructions, your shares will not be counted for purposes of determining whether a quorum is present at the Piedmont special meeting or be voted at the Piedmont special meeting, and, if a quorum is present, that will have the same effect as voting “AGAINST” the Piedmont merger proposal.

Piedmont CDI holders are entitled to receive notice of, and attend as guests (but not vote at), the Piedmont special meeting and may instruct the CDI Depositary to vote the shares underlying their Piedmont CDIs by following the instructions on the Piedmont CDI voting instruction form. The CDI Depositary will vote the applicable shares on behalf of each applicable Piedmont CDI holder at the Piedmont special meeting, in accordance with the instructions received via the Piedmont CDI voting instruction form. If you are a Piedmont CDI holder, your vote must be received no later than [5:00] p.m., Eastern Time, on [  ], 2025 (being [7:00 a.m.], Australian Eastern Standard Time, on [  ], 2025).

If you have any questions about the merger, please contact Piedmont at (704) 461-8000 or write to Piedmont, 42 E Catawba Street, Belmont, North Carolina 28012, Attention: [  ].

If you have any questions about how to vote or direct a vote in respect of your shares of Piedmont common stock, you may contact Piedmont’s proxy solicitor:

YOUR VOTE IS VERY IMPORTANT, REGARDLESS OF THE NUMBER OF SHARES OF PIEDMONT COMMON STOCK THAT YOU OWN. WHETHER OR NOT YOU EXPECT TO PARTICIPATE IN THE PIEDMONT SPECIAL MEETING, PLEASE VOTE AS PROMPTLY AS POSSIBLE TO ENSURE YOUR REPRESENTATION AT THE PIEDMONT SPECIAL MEETING. YOU MAY VOTE YOUR SHARES IN ADVANCE OF THE PIEDMONT SPECIAL MEETING OF STOCKHOLDERS VIA THE INTERNET, OR, IF YOU RECEIVED A PROXY CARD OR VOTING INSTRUCTION FORM, BY TELEPHONE OR BY MAIL, OR YOU MAY VOTE DURING THE MEETING BY ATTENDING THE MEETING AND VOTING ELECTRONICALLY. IF YOU VOTE VIA THE INTERNET, BY TELEPHONE OR PLAN TO VOTE ELECTRONICALLY DURING THE SPECIAL MEETING, YOU DO NOT NEED TO MAIL IN A PROXY CARD.

The accompanying proxy statement/prospectus provides a detailed description of the merger agreement, the Piedmont merger proposal and the related agreements and transactions. We urge you to read the accompanying proxy statement/prospectus, including any documents incorporated by reference into the accompanying proxy statement/prospectus, and its annexes carefully and in their entirety. If you have any questions concerning the merger, the Piedmont merger proposal, the other Proposals or the accompanying proxy statement/prospectus, would like additional copies of the accompanying proxy statement/prospectus or need help voting your shares, please contact Piedmont’s proxy solicitor, Sodali & Co., at the address and telephone numbers listed below:

Certain terms that are defined in and frequently used in this proxy statement/prospectus may be helpful for you to have in mind at the outset. Unless otherwise specified or if the context so requires, the following terms have the meanings set forth below for purposes of this proxy statement/prospectus:

The following are brief answers to certain questions that you, as a stockholder of Piedmont, may have regarding the transaction and the other matters being considered at the Piedmont special meeting. You are urged to carefully read this proxy statement/prospectus and the other documents referred to or incorporated by reference in this proxy statement/prospectus in their entirety because this section may not provide all the information that is important to you regarding these matters. Please refer to the section of this proxy statement/prospectus entitled “Summary” beginning on page 15 for a summary of important information regarding the merger agreement, the transaction and the related transactions. Additional important information is contained in the annexes to, and the documents incorporated by reference into, this proxy statement/prospectus. You may obtain the information incorporated by reference in this proxy statement/prospectus, without charge, by following the instructions under the section of this proxy statement/prospectus entitled “Where You Can Find Additional Information” beginning on page 296.

You should consider carefully the following risk factors, as well as the other information set forth in and incorporated by reference into this proxy statement/prospectus, before making a decision on the Piedmont merger proposal, the adjournment proposal or the advisory compensation proposal. In the event you become a holder of Sayona ADSs or Sayona ordinary shares following completion of the transaction, you will be subject to all risks inherent in the business of Sayona in addition to the risks relating to Piedmont. The market value of your Sayona ADSs or Sayona ordinary shares will reflect the performance of the business relative to, among other things, that of the competitors of Sayona and Piedmont and general economic, market and industry conditions. The value of your investment may increase or may decline and could result in a loss. You should carefully consider the following factors as well as the other information contained in and incorporated by reference into this proxy statement/prospectus. For information about the filings incorporated by reference in this proxy statement/prospectus, see the section of this proxy statement/prospectus entitled “Where You Can Find Additional Information” beginning on page 296.

Upon completion of the transaction, as described under the section of this proxy statement/prospectus entitled “The Merger Agreement—Effect of the Merger on Capital Stock; Merger Consideration” beginning on page 135, each eligible share of Piedmont common stock will be converted as follows: (1) each Piedmont CDI representing 1/100th of an eligible share of Piedmont common stock issued and outstanding as of a record date prior to the effective time of the merger to be established pursuant to the ASX settlement rules will be converted into the right to receive 5.27 Sayona ordinary shares (or 0.035133 Sayona ordinary shares if, prior to the effective time of the merger, Sayona effects the Sayona share consolidation); and (2) each share of Piedmont common stock issued and outstanding immediately prior to the effective time of the merger and not represented by a Piedmont CDI will be converted into the right to receive 0.35133 Sayona ADSs.

Because the exchange ratio is fixed, the value of the merger consideration will depend on the Sayona ordinary share price as of the closing date. The merger consideration will not be adjusted for changes in the market price of Sayona ordinary shares, Piedmont common stock, Piedmont CDIs or in currency exchange rates between the date of signing the merger agreement and the closing date (as defined herein). In addition, there will be a lapse of time between the date on which Piedmont stockholders vote on the Piedmont merger proposal at the Piedmont special meeting and the date on which Piedmont stockholders entitled to receive the merger consideration actually receive the merger consideration.

The market value of the merger consideration and the market value of Piedmont common stock and Piedmont CDIs on the closing date may vary significantly from their respective values on the date that the merger agreement was executed or at other dates, such as the date of this proxy statement/prospectus or the date of the Piedmont special meeting. These changes may result from a variety of factors, including changes in Sayona’s or Piedmont’s respective businesses, operations or prospects, regulatory considerations and general business, market, industry or economic conditions. The merger consideration will not be adjusted to reflect the comparative value of the Australian dollar and the U.S. dollar or the market value of Sayona ordinary shares, the Piedmont common stock or the Piedmont CDIs. Therefore, the market value of the merger consideration that a Piedmont stockholder was entitled to receive on the date that the merger agreement was executed could vary significantly from the value of the merger consideration on the date of this proxy statement/prospectus, the date of the Piedmont special meeting or the closing date.

Sayona shareholders and Piedmont stockholders are urged to obtain current market quotations for Sayona ordinary shares, Piedmont common stock and Piedmont CDIs. See the section entitled “Comparative Per Share Market Price” beginning on page 66 of this proxy statement/prospectus for more information about the market value of Sayona ordinary shares, Piedmont common stock and Piedmont CDIs on certain dates.

Completing the merger is subject to several conditions, not all of which are controllable by Piedmont or Sayona. Accordingly, the date on which Piedmont stockholders will receive the merger consideration is uncertain.

Upon completion of the transaction, Piedmont stockholders who receive Sayona ADSs or Sayona ordinary shares in the transaction will become Sayona ADS holders or Sayona shareholders, respectively. Sayona’s financial position may differ from its financial position before the completion of the merger, and the results of operations of Sayona following the merger may be affected by some factors that are different from those currently affecting the results of operations of Sayona and those currently affecting the results of operations of Piedmont. Accordingly, the market price and performance of Sayona ADSs and Sayona ordinary shares is likely to be different from the market price and performance of Sayona ordinary shares, Piedmont common stock or Piedmont CDIs in the absence of the merger. For a discussion of the businesses of Piedmont and Sayona and of some important factors to consider in connection with those businesses, see the section of this proxy statement/prospectus entitled “Business of Sayona” beginning on page 241 and the documents incorporated by reference in this proxy statement/prospectus and referred to in the section of this proxy statement/prospectus entitled “Where You Can Find Additional Information” beginning on page 296.

The completion of the transaction is subject to the satisfaction or waiver of a number of conditions as set forth in the merger agreement, including, among others, (i) approval of the Piedmont merger proposal in accordance with the Delaware General Corporation Law (the “DGCL”) and Piedmont’s organizational documents at the Piedmont special meeting, (ii) approval of the Sayona merger proposals in accordance with the Australian Corporations Act 2001 (Cth), as in force or as modified (including via any ASIC Relief or Requirements) from time to time (the “Australian Corporations Act”), the listing rules of ASX and the organizational documents of Sayona at the Sayona extraordinary general meeting, (iii) approval for listing on the Nasdaq of the Sayona ADSs to be issued in connection with the transaction, subject to official notice of issuance, (iv) authorization for listing the Sayona ordinary shares issuable to Piedmont stockholders pursuant to the merger agreement on the ASX, (v) Australian Securities and Investments Commission (“ASIC”) and the ASX having provided to Sayona and Merger Sub the consents, approvals, waivers, relief and exemptions required for the merger and the Sayona share issuance (as defined herein), (vi) the absence of (a) any order, decree, ruling, injunction or other action that is in effect (whether temporary, preliminary or permanent) restraining, enjoining or otherwise prohibiting the consummation of the merger having been issued by any governmental entity having jurisdiction over Sayona, Piedmont and Merger Sub, and (b) any law that makes the consummation of the merger illegal or otherwise prohibited having been adopted, (vii) effectiveness of the registration statement for Sayona ordinary shares to be issued in the transaction, including the Sayona ordinary shares represented by the Sayona ADSs (of which this proxy statement/prospectus forms a part), and of the registration statement on Form F-6 relating to the Sayona ADSs and the absence of any stop order suspending that effectiveness or any proceedings for that purpose pending before the SEC, and (viii) other customary closing conditions, including the accuracy of each party’s representations and warranties (subject to specified materiality qualifiers), and each party’s compliance in all material respects with its covenants and agreements contained in the merger agreement. There can be no assurance as to when these conditions will be satisfied or waived, if at all, or that other events will not intervene to delay or result in the failure to complete the transaction.

If the transaction is not completed, or if there are significant delays in completing the transaction, Sayona’s and Piedmont’s future business and financial results and the trading prices of Piedmont common stock, Piedmont CDIs, Sayona ordinary shares or Sayona ADSs, as applicable, could be negatively affected, and each of Sayona and Piedmont would be subject to several risks, including the following: (i) there may be negative reactions from the financial markets due to the fact that current trading prices of Piedmont common stock, Piedmont CDIs or Sayona ordinary shares may reflect a market assumption that the transaction will be completed; and (ii) the attention of management may have been diverted to the transaction rather than their own operations and pursuit of other opportunities that could have been beneficial to their respective businesses.

The obligations of Canaccord (as defined herein) to underwrite the closing equity raise are subject to the following conditions precedent (in addition to the satisfaction of the conditions precedent to the effectiveness of the Sayona placement agreement and to underwriting of the Sayona equity raise, which have been satisfied): (i) the ASX must not have indicated that it will not grant permission for the official quotation of the Sayona ordinary shares issued in the closing equity raise on an unconditional basis (or indicating that approval will be granted on a conditional basis where such condition would, in the reasonable opinion of Canaccord, not have a material adverse effect on the Sayona equity raise) on or before 10:00 a.m. (Sydney time) on the closing equity raise settlement date; (ii) Sayona must have provided the certificate in the form set out in Annex B to the Sayona placement agreement dated as at the closing equity raise settlement date; (iii) a cleansing notice must have been lodged with the ASX in accordance with the Sayona placement agreement in relation to the Sayona ordinary shares issued in the Sayona equity raise; (iv) the shareholders of Sayona must have approved the closing equity raise by appropriate majority in a general meeting for all purposes by the date that is 28 days after the notice of meeting has been released to the ASX (or by a later date if the meeting is adjourned or postponed) by the date of the Sayona extraordinary general meeting; (v) closing of the merger must have occurred on or prior to July 31, 2025 (Sydney time) (or such later date as may be agreed between Sayona and Canaccord, acting reasonably); and (vi) RCF must have paid the subscription amount under the RCF subscription agreement (as defined herein) before 10:00 am Sydney time on the closing equity raise settlement date, such obligation to subscribe being further subject to certain conditions precedent and termination rights under the RCF subscription agreement for RCF and Sayona. Canaccord also has a customary right, under certain circumstances, to terminate the Sayona placement agreement before 4:00 p.m. Sydney time on the closing equity raise settlement date under certain circumstances. There can be no assurance as to when these conditions will be satisfied or waived, if at all, or that other events will not intervene to delay or result in the failure to complete the closing equity raise. See “The Merger—Equity Raises of Sayona and Piedmont—Closing Equity Raise” on page 113 for additional information on the closing equity raise.

There is a risk that some or all of the expected benefits of the transaction may fail to materialize or be realized fully, or may not occur within the time periods anticipated by Sayona and Piedmont. The realization of such benefits may be affected by a number of factors, many of which are beyond the control of Sayona and Piedmont, including, for example, differences in corporate culture, loss of, or reduction in, key personnel, expert capability or employee productivity, failure to procure or retain employees of Sayona, required changes to operating models, or the diversion of management’s attention. The challenge of integrating previously independent businesses makes evaluating the business and future financial prospects of the combined company following the transaction difficult. Piedmont and Sayona have operated and, until completion of the transaction, will continue to operate, independently. The success of the transaction, including anticipated benefits and cost savings, will depend, in part, on the ability to successfully integrate the operations of both companies in a manner that results in various benefits, including, among other things, the expected optimization of the North American Lithium project (“NAL”), currently owned 75% by Sayona and 25% by Piedmont, through consolidated offtake economics, complimentary technical capabilities, and material logistics, procurement and marketing synergies with aligned economic interests in pursuing North American Lithium brownfield expansion. A failure to integrate the businesses in the time and manner contemplated by Sayona and Piedmont, or a failure to achieve the expected benefits of integration may impact the financial performance, operation and position of the combined company. Furthermore, Piedmont will be a material part of the combined company’s business. If the Piedmont part of the combined company’s business does not perform as expected after completing the merger, this could have a material adverse impact the combined company’s financial position and performance.

The past financial performance of each of Piedmont and Sayona may not be indicative of the future financial performance of the combined company. Moreover, Sayona and Piedmont, as standalone entities, have particular accounting policies and methods which are fundamental to how they record and report their financial position and results of operations. Sayona and Piedmont may have exercised judgment in selecting accounting policies or methods, which might have been reasonable in the circumstances yet resulted in reporting materially different outcomes than would have been reported under the other company’s policies and methods. The integration of Sayona’s and Piedmont’s accounting functions may lead to revisions of these accounting policies, which may adversely impact the merged entity’s reported results of operations, financial position, or performance. Sayona and Piedmont also have different year-end reporting periods, with Sayona reporting on a

June 30th year-end basis and Piedmont reporting on a calendar year-end basis. The application of acquisition accounting and the alignment of financial year ends after completion of the transaction will likely impact the combined company’s reported results of operations, financial position or performance.

Piedmont and Sayona have incurred significant financial services, accounting, tax and legal fees in connection with negotiating and evaluating the terms of the transaction. Additional significant unanticipated costs may be incurred in the course of coordinating the businesses of Piedmont and Sayona after completion of the transaction. Even if the transaction is not completed, Piedmont and Sayona will need to pay certain costs relating to the transaction incurred prior to the date the transaction was abandoned, such as financial advisory, accounting, tax, legal, filing and printing fees. Such costs may be significant and could have an adverse effect on the parties’ future results of operations, cash flows and financial condition.

Piedmont may also be required to pay Sayona a termination fee of $2.62 million if the merger agreement is terminated under the circumstances specified in the merger agreement, and Sayona may be required to pay Piedmont a termination fee of $2.62 million if the merger agreement is terminated under the circumstances specified in the merger agreement. For more information, see the sections entitled “The Merger Agreement—Termination—Termination Fees Payable by Sayona” beginning on page 174 and “The Merger Agreement—Termination—Termination Fees Payable by Piedmont” beginning on page 175.

Pursuant to the Sayona equity raise (as defined herein), Sayona issued 1,250,000,000 Sayona ordinary shares at the issue price of AU$0.032 (approximately $0.02, at the then-prevailing exchange rate) per Sayona ordinary share. In connection with the completion of the transaction, (i) Sayona expects to issue approximately 11,700,000,000 new Sayona ordinary shares (or 78,000,000 new Sayona ordinary shares if, prior to the completion of the transaction, Sayona effects the Sayona share consolidation) (including, in each case, Sayona ordinary shares represented by Sayona ADSs) as the merger consideration, (ii) certain Piedmont equity awards are required to be converted into equity awards of Sayona pursuant to the merger agreement and, (iii) in connection with the closing equity raise, Sayona expects to issue an additional 2,156,250,000 Sayona ordinary shares at the issue price of AU$0.032 (approximately $0.02, at the prevailing exchange rate as of June 2, 2025) per Sayona ordinary share (or 14,375,000 Sayona ordinary shares at the issue price of AU$4.80 (approximately $3.12, at the prevailing exchange rate as of June 2, 2025) per Sayona ordinary share if, prior to such issuance of Sayona ordinary shares, Sayona effects the Sayona share consolidation). The issuance of new Sayona ordinary shares (including those represented by Sayona ADSs) in the transaction, the Sayona equity raise and the closing equity raise could have the effect of depressing the market price of Sayona ordinary shares. The increase in the number of Sayona ordinary shares and Sayona ADSs may lead to sales of such Sayona ordinary shares or Sayona ADSs or the perception that such sales may occur, either of which may adversely affect the market for, and the market value of, Sayona ordinary shares and Sayona ADSs.

Sayona currently projects that the transaction will result in a number of benefits, including the combined company being among the largest hard rock lithium producers in North America and strengthening Sayona’s balance sheet to fund and accelerate growth projects, and that it will ultimately be accretive to Sayona’s cash flow per share and free cash flow per share. This projection is based on preliminary estimates that may materially change. Future events and conditions could reduce or delay the accretion that is currently projected or result in the transaction being dilutive to Sayona’s cash flow per share and free cash flow per share, including adverse changes in market conditions, additional transaction- and integration-related costs and other factors such as the failure to realize some or all of the benefits anticipated in the transaction. Any dilution of, reduction in or delay of any accretion to, Sayona’s cash flow per share and free cash flow per share could cause the price of Sayona ordinary shares and the implied value of the Sayona ADSs to decline or grow at a reduced rate.

The unaudited pro forma combined financial information included in this proxy statement/prospectus has been prepared using the Sayona annual financial statements, the Sayona interim financial statements, the Piedmont annual financial statements and certain other financial information of Piedmont, is presented for

illustrative purposes only and should not be considered to be an indication of the results of operations or financial condition of the combined company following the transaction. In addition, the unaudited pro forma combined financial information included in this proxy statement/prospectus is based in part on certain assumptions regarding the transaction. These assumptions may not prove to be accurate, and other factors may affect the combined company’s results of operations or financial condition following the transaction. Accordingly, the historical and unaudited pro forma combined financial information included in this proxy statement/prospectus does not necessarily represent the combined company’s results of operations and financial condition had Piedmont and Sayona operated as a combined entity during the periods presented, or of the combined company’s results of operations and financial condition following completion of the transaction. The combined company’s potential for future business success and operating profitability must be considered in light of the risks, uncertainties, expenses and difficulties that may be encountered by recently combined companies.

In preparing the unaudited pro forma combined financial information contained in this proxy statement/prospectus, Sayona has given effect to the completion of the transaction. The unaudited pro forma combined financial information does not reflect all of the costs that are expected to be incurred by Piedmont and Sayona in connection with the transaction. For more information, see the section of this proxy statement/prospectus entitled “Sayona Unaudited Pro Forma Combined Financial Information,” including the notes thereto, beginning on page 181.

Certain conditions to Sayona’s and Piedmont’s obligations, respectively, to complete the transaction, including that the Sayona ADSs be authorized for listing on the Nasdaq, subject to official notice of issuance, may be waived by either Sayona or Piedmont, in whole or in part, to the extent legally permissible, either unilaterally or by agreement. In the event that any such waiver does not require re-solicitation of Sayona’s shareholders or Piedmont’s stockholders or the amendment of this proxy statement/prospectus or any re-solicitation of proxies or voting cards (as applicable), the parties will have the discretion to complete the transaction without seeking further approval of Sayona shareholders or Piedmont stockholders, as applicable.

The Piedmont board has received an opinion from J.P. Morgan, Piedmont’s financial advisor, dated November 18, 2024, to the effect that, as of the date of the opinion and based on and subject to the circumstances and conditions existing as of the date of the written opinion and various assumptions and limitations described in J.P. Morgan’s written opinion, the exchange ratio in the proposed merger was fair, from a financial point of view, to the holders of Piedmont common stock, but has not obtained an updated opinion as of the date of this proxy statement/prospectus. Changes in the operations and prospects of Sayona or Piedmont, general market and economic conditions and other factors that may be beyond the control of Sayona or Piedmont, and on which the forecasts and assumptions used by Piedmont’s financial advisor in connection with rendering its opinion may have been based, may significantly alter the value of Sayona or Piedmont or the prices of Sayona ordinary shares, shares of Piedmont common stock or Piedmont CDIs by the time the transaction is completed. The opinion did not speak as of the time the transaction will be completed or as of any date other than the date of such opinion and the Piedmont board does not anticipate asking J.P. Morgan to update its opinion. However, the Piedmont board’s recommendation that Piedmont stockholders vote “FOR” approval of the Piedmont merger proposal, “FOR” approval of the adjournment proposal and “FOR” approval of the advisory compensation proposal is made as of the date of this proxy statement/prospectus. For a more complete description of the written opinion that the Piedmont board received from its financial advisor, see the section of this proxy statement/prospectus entitled “The Merger—Opinion of J.P. Morgan Securities LLC, Piedmont’s Financial Advisor” beginning on page 91. A copy of the opinion of J.P. Morgan is attached as Annex C to this proxy statement/prospectus and is incorporated by reference herein in its entirety.

Under the merger agreement, Piedmont, Sayona and their respective subsidiaries have agreed to certain restrictions on the conduct of their respective businesses and generally must operate their respective businesses in the ordinary course prior to completing the transaction (unless Piedmont or Sayona obtains the other’s written consent, as applicable, which is not to be unreasonably withheld, conditioned or delayed), which may restrict Piedmont’s and Sayona’s ability to pursue certain of their respective business strategies. These restrictions may prevent Piedmont and Sayona from pursuing otherwise attractive business opportunities, making certain investments or acquisitions, selling assets, engaging in capital expenditures in excess of certain agreed limits, incurring indebtedness or making changes to Piedmont’s and Sayona’s respective businesses prior to the completion of the transaction or termination of the merger agreement, as applicable. These restrictions could have an adverse effect on Piedmont’s and Sayona’s business, financial results, financial condition or share price.

In addition, the merger agreement prohibits Piedmont and Sayona from (i) initiating, soliciting, proposing, knowingly encouraging or knowingly facilitating (including by way of furnishing non-public information) any inquiry or the making of any proposal or offer that constitutes, or would reasonably be expected to result in, a Sayona competing proposal or a Piedmont competing proposal, as the case may be, (ii) engaging in, continuing or otherwise participating in any discussions with any person with respect to or negotiations with any person with respect to, relating to, or in furtherance of a Sayona competing proposal or Piedmont competing proposal, as the case may be, or any inquiry, proposal or offer that would reasonably be expected to lead to a Sayona competing proposal or Piedmont competing proposal, as the case may be, (iii) furnishing any non-public information regarding Sayona or its subsidiaries or Piedmont or its subsidiaries, as the case may be, or access to the properties, assets or employees of Sayona or its subsidiaries or Piedmont or its subsidiaries, as the case may be, to any person in connection with or in response to any Sayona competing proposal or Piedmont competing proposal, as the case may be, or any inquiry, proposal or offer that would reasonably be expected to lead to a Sayona competing proposal or Piedmont competing proposal, as the case may be, (iv) approving or recommending, or proposing to approve or recommend, or executing or entering into any letter of intent or agreement in principle, or other agreement providing for a Sayona competing proposal or Piedmont competing proposal, as the case may be (other than certain confidentiality agreements entered into as permitted by the merger agreement), or (v) submitting any Sayona competing proposal or Piedmont competing proposal to the vote of Sayona shareholders or Piedmont stockholders, as the case may be. Piedmont may also be required to pay Sayona a termination fee of $2.62 million if the merger agreement is terminated under the circumstances specified in the merger agreement, and Sayona may be required to pay Piedmont a termination fee of $2.62 million if the merger agreement is terminated under the circumstances specified in the merger agreement.

These provisions might discourage a third party that has an interest in acquiring all or a significant part of either Piedmont or Sayona from considering or proposing an acquisition proposal, even if that party were prepared to pay consideration with a higher per-share value than the currently proposed merger consideration, in the case of Piedmont, or that party were prepared to enter into an agreement that may be more favorable to Sayona or its shareholders, in the case of Sayona. Furthermore, the termination fees described above may result in a potential competing acquiror proposing to pay a lower per-share price to acquire the applicable party than it might otherwise have proposed to pay because of the added expense of the termination fee that may become payable by such party in certain circumstances.

If the transaction is not completed for any reason, including as a result of Piedmont stockholders failing to approve the Piedmont merger proposal, the ongoing businesses of Piedmont may be adversely affected and, without realizing any of the anticipated benefits of having completed the transaction, Piedmont would be subject to a number of risks, including the following:

If the merger agreement is terminated and the Piedmont board seeks another merger, business combination or other transaction, Piedmont stockholders cannot be certain that Piedmont will find a party willing to offer equivalent or more attractive consideration than the merger consideration Piedmont stockholders would receive from Sayona in the transaction. Piedmont may also be required to pay Sayona a termination fee of $2.62 million if the merger agreement is terminated under the circumstances specified in the merger agreement.

See the section of this proxy statement/prospectus entitled “The Merger Agreement—Termination” beginning on page 173 for a more complete discussion of the circumstances under which the merger agreement could be terminated and when the termination fee may be payable by Piedmont.

In considering the recommendation of the Piedmont board, you should be aware that Piedmont’s directors and executive officers may have interests in the transaction that are different from, or in addition to, those of Piedmont stockholders generally. These interests may include, among others, the treatment of outstanding Piedmont equity awards pursuant to the merger agreement, the payment of severance benefits and acceleration of outstanding Piedmont equity awards upon certain terminations of employment, and the combined company’s agreement to indemnify Piedmont directors and executive officers against certain claims and liabilities. These interests are described in more detail in the section of this proxy statement/prospectus entitled “The Merger—Interests of Piedmont’s Directors and Executive Officers in the Merger” beginning on page 104.

Either Piedmont or Sayona may terminate the merger agreement if the transaction has not been completed by September 30, 2025. However, this right to terminate the merger agreement will not be available to Piedmont or Sayona if such party’s failure to fulfill any material covenant or agreement under the merger agreement has been the cause of, materially contributed to, or resulted in the failure of the transaction to be completed on or before such time. For more information, see the section of this proxy statement/prospectus entitled “The Merger Agreement—Termination” beginning on page 173.

As a foreign private issuer under the U.S. Exchange Act, Sayona would be exempt from certain rules under the U.S. Exchange Act, and would not be required to file periodic reports and financial statements with the SEC as frequently or as promptly as companies whose securities are registered under the U.S. Exchange Act but are not foreign private issuers, or to comply with Regulation Fair Disclosure under the U.S. Exchange Act (“Regulation FD”), which restricts the selective disclosure of material non-public information. In addition, Sayona would be (a) exempt from certain disclosure and procedural requirements applicable to proxy solicitations under Section 14 of the U.S. Exchange Act and (b) subject to reduced disclosure obligations regarding executive compensation. Further, the members of the Sayona board, officers and principal shareholders would be exempt from the reporting and “short-swing” profit recovery provisions of Section 16 of the U.S. Exchange Act. Accordingly, following the closing, there may be less publicly available information concerning Sayona than there is for companies whose securities are registered under the U.S. Exchange Act but are not foreign private issuers, and such information may not be provided as promptly as it is provided by such other companies. In addition, certain information may be provided by Sayona in accordance with Australian law, which may differ in substance or timing from such disclosure requirements under the U.S. Exchange Act.

Further, as a foreign private issuer, Sayona would be subject to less stringent corporate governance listing requirements under Nasdaq rules. Subject to certain exceptions, the rules of the Nasdaq permit a foreign private issuer to follow its home country practice in lieu of the corporate governance listing requirements of the Nasdaq, including, for example, certain internal controls as well as certain board, committee and director independence requirements, provided that such foreign private issuer discloses the Nasdaq rules it does not follow and the home country practices it follows in lieu thereof. Sayona expects to be a foreign private issuer and follow Australian practices in lieu of certain corporate governance listing requirements of the Nasdaq and, therefore, will initially provide this disclosure on the “Corporate Governance” page of its website (https://sayonamining.com.au/corporate-governance/) by closing of the merger and listing of the Sayona ADSs to be issued in connection therewith. Thereafter, to the extent such disclosure is applicable and required, Sayona will provide this disclosure in its annual reports on Form 20-F filed with the SEC or on its website. Accordingly, you may not have the same protections afforded to shareholders of companies that are required to comply with all of the Nasdaq corporate governance requirements. The information contained on or linked from Sayona’s website is not incorporated by reference in, or in any way part of, this proxy statement/prospectus.

Sayona could lose its status as a foreign private issuer under current SEC rules and regulations if more than 50% of Sayona’s outstanding voting securities become directly or indirectly held of record by U.S. holders and any one of the following is true: (a) the majority of Sayona’s directors or Executive KMP are U.S. citizens or residents; (b) more than 50% of Sayona’s assets are located in the United States; or (c) Sayona’s business is administered principally in the United States. If Sayona loses its status as a foreign private issuer in the future, it will no longer be exempt from the rules described above and, among other things, will be required to file periodic reports and annual and quarterly financial statements as if it were a United States domestic issuer. If this were to happen, Sayona would likely incur substantial costs in fulfilling these additional regulatory requirements and members of Sayona’s management would likely have to divert time and resources from other responsibilities to ensuring these additional regulatory requirements are fulfilled.

In addition, Sayona qualifies as an EGC as defined in Section 2(a)(19) of the U.S. Securities Act. As such, Sayona expects to take advantage of certain exemptions from various reporting requirements applicable to public companies that are not EGCs, including (a) the exemption from the auditor attestation requirements with respect to internal control over financial reporting under Section 404 of the Sarbanes-Oxley Act, (b) the exemptions from say-on-pay, say-on-frequency and say-on-golden parachute voting requirements and (c) reduced disclosure obligations regarding executive compensation in Sayona’s periodic reports and proxy statements. As a result, holders of Sayona ordinary shares and Sayona ADSs may not have access to certain information they deem important. Sayona will remain an EGC until the earliest of (a) the last day of the fiscal year (i) following the fifth anniversary of the closing of the merger, (ii) in which Sayona has total annual gross revenue of at least $1.235 billion (as adjusted for inflation pursuant to SEC rules from time to time) or (iii) in which Sayona is deemed to be a large accelerated filer, which means the market value of Sayona ordinary shares and Sayona ADSs that are held by non-affiliates exceeds $700 million as of the last business day of the prior second fiscal quarter, and (b) the date on which Sayona has issued more than $1.0 billion in non-convertible debt during the prior three year period.

Sayona cannot predict if investors will find the Sayona ordinary shares or Sayona ADSs less attractive because Sayona will rely on these exemptions. If some investors find the Sayona ordinary shares or Sayona ADSs less attractive as a result, there may be a less active trading market for the Sayona ordinary shares or Sayona ADSs and their prices may be more volatile.

Even if Sayona no longer qualifies as an EGC, as long as Sayona continues to qualify as a foreign private issuer under the U.S. Exchange Act, subject to SEC rule changes, Sayona will be exempt from certain provisions of the U.S. Exchange Act that are applicable to U.S. domestic public companies, including:

Sayona is a public limited company incorporated under the laws of Queensland, Australia. All of Sayona’s current directors are non-residents of the United States and substantially all of their assets may be located outside the United States. As a result, there may be additional complexities and practical challenges involved if you wish to:

Sayona has appointed Puglisi & Associates as its agent to receive service of process with respect to any action brought against Sayona under the federal securities laws of the United States.

Pursuant to the Sayona equity raise, Sayona issued 1,250,000,000 Sayona ordinary shares at the issue price of AU$0.032 (approximately $0.02, at the then-prevailing exchange rate) per Sayona ordinary share. In connection with the completion of the transaction, (i) Sayona expects to issue approximately 11,700,000,000 new Sayona ordinary shares (or 78,000,000 new Sayona ordinary shares if, prior to the completion of the transaction, Sayona effects the Sayona share consolidation) (including, in each case, Sayona ordinary shares represented by Sayona ADSs) as the merger consideration, (ii) certain Piedmont equity awards are required to be converted into equity awards of Sayona pursuant to the merger agreement and, (iii) in connection with the closing equity raise, Sayona expects to issue an additional 2,156,250,000 Sayona ordinary shares at the issue price of AU$0.032 (approximately $0.02, at the prevailing exchange rate as of June 2, 2025) per Sayona ordinary share (or 14,375,000 Sayona ordinary shares at the issue price of AU$4.80 (approximately $3.12, at the prevailing exchange rate as of June 2, 2025) per Sayona ordinary share if, prior to such issuance of Sayona ordinary shares, Sayona effects the Sayona share consolidation). The issuance of new Sayona ordinary shares (including those represented by Sayona ADSs) could have the effect of depressing the market price of Sayona ordinary shares. The increase in the number of Sayona ordinary shares and Sayona ADSs may lead to sales of such Sayona ordinary shares or Sayona ADSs or the perception that such sales may occur, either of which may adversely affect the market for, and the market value of, Sayona ordinary shares and Sayona ADSs.

Further, as opportunities present themselves, Sayona may enter into financing or similar arrangements in the future, including the issuance of debt or equity securities. If Sayona issues Sayona ordinary shares, Sayona ADSs or securities convertible into Sayona ordinary shares, Sayona shareholders or Sayona ADS holders would experience additional dilution, and as a result, the price of Sayona ordinary shares and Sayona ADSs may decline.

No Sayona ADSs have been issued or listed on any U.S. stock exchange; however, Sayona expects to list the Sayona ADSs on the Nasdaq. Sayona has submitted to, and discussed with, the Nasdaq its initial listing application with respect to the Sayona ADSs and expects to know the Nasdaq’s determination regarding such

application prior to the Piedmont special meeting and the Sayona extraordinary general meeting. Following the closing, even if the Sayona ADSs are listed on the Nasdaq, an active trading market for the Sayona ADSs may never develop or, if developed, it may not be sustained. If Sayona and Piedmont waive the Nasdaq listing condition to their respective obligations to complete the transaction, including as a result of Nasdaq not approving Sayona’s initial listing application with respect to the Sayona ADSs, it may be more difficult to develop or sustain such an active trading market.

To the extent an active public market for Sayona ADSs does not develop, the market price and liquidity of Sayona ADSs may be adversely affected. Sayona shareholders may be unable to sell their Sayona ADSs without depressing the market price for the Sayona ADSs, or at all, unless a market can be established and sustained.

Sayona ordinary shares are quoted in Australian dollars on the ASX and Sayona ADSs are expected to be quoted in U.S. dollars on the Nasdaq. Dividends to be paid to holders of Sayona ADSs in respect of Sayona ordinary shares, if any, will be paid in U.S. dollars in accordance with the deposit agreement. Sayona’s historical financial statements included in this proxy statement/prospectus and any financial statements filed with the SEC in the future will be prepared in Australian dollars. Fluctuations in the exchange rate between the U.S. dollar and the Australian dollar may affect, among other matters, the U.S. dollar value of the Sayona ADSs and of any dividends in respect thereof. While the market price of Sayona ADSs is expected to fluctuate according to the market price of Sayona ordinary shares and according to changes in the exchange rate between the U.S. dollar and the Australian dollar, there is no guarantee that this relationship will be observed at all times, or at any time. The market price of Sayona ADSs may differ from the market price of Sayona ordinary shares in U.S. dollar terms for a number of reasons, including the relative liquidity of Sayona ADSs and Sayona ordinary shares. See “—An active trading market for Sayona ADSs may not develop, which would adversely affect the liquidity and price of Sayona ADSs.”

Certain of the rights associated with Piedmont common stock and Piedmont CDIs are different from the rights associated with Sayona ordinary shares. For example, the laws of Australia, the jurisdiction in which Sayona is incorporated, and the Constitution of Sayona adopted by shareholders on November 28, 2024 (the “Constitution”), (a) do not afford appraisal rights to dissenting shareholders in the form typically available to stockholders of Delaware corporation and (b) provide a first lien to Sayona on each partly paid share for all unpaid calls and instalments due on that share and each share for any amounts the company is required by law to pay and has paid in respect of that share, such lien extending to all dividends payable on the share and the proceeds of sale of the share. See the section of this proxy statement/prospectus entitled “Comparison of Rights of Sayona Shareholders and Piedmont Stockholders” beginning on page 220 for a discussion of the different rights associated with Sayona ordinary shares and Piedmont common stock.

In addition, the rights of holders of Sayona ordinary shares will be governed by the Australian Corporations Act, the Constitution and the ASX Listing Rules, and the rights of holders of Sayona ADSs will be governed by the terms and conditions of the deposit agreement and New York law, and are expected to be governed by Nasdaq listing rules. There are differences between the rights presently enjoyed by holders of Piedmont common stock and the rights to which the holders of Sayona ADSs will be entitled following the transaction. In some cases, the holders of Sayona ADSs may not be entitled to important rights to which they would have been entitled as holders of Piedmont common stock and will not be entitled to the same rights as holders of Sayona ordinary shares (except following cancellation of their Sayona ADSs for withdrawal and delivery of Sayona ordinary shares represented thereby).

For more information, see the sections of this proxy statement/prospectus entitled “Description of Sayona American Depositary Shares” beginning on page 210 and “Comparison of Rights of Sayona Shareholders and Piedmont Stockholders” beginning on page 220.

Sayona’s Constitution provides that each member of Sayona submits to the non-exclusive jurisdiction of the Supreme Court of Queensland, the Federal Court of Australia and the courts which may hear appeals from those courts. Such provision can result in increased costs to bring a claim, discourage claims by investors in Sayona ordinary shares or limits such investors’ ability to bring a claim in a judicial forum they find favorable. Furthermore, there may be additional complexities and practical challenges involved if an investor seeks enforce, in the United States, judgments obtained against Sayona’s directors or Sayona in such courts in any action, including actions under the civil liability provisions of U.S. securities laws. For more information, see the section of this proxy statement/prospectus entitled “Service of Process and Enforceability of Civil Liabilities” on page 294.

No condition, stipulation or provision of Sayona’s Constitution will relieve Sayona from its respective obligations to comply with the U.S. federal securities laws and the rules and regulations thereunder, and investors in Sayona ordinary shares cannot waive such compliance.

The aforementioned non-exclusive jurisdiction provision contained in Sayona’s Constitution is not applicable to holders of Sayona ADSs in their capacity as Sayona ADS Holders, who will be subject to the jurisdiction provision of the deposit agreement. See “–Sayona ADS Holders will not be holders of Sayona ordinary shares and will not have shareholder rights.” and “–Sayona ADS Holders may not be entitled to a jury trial with respect to claims arising under the deposit agreement, which could result in less favorable outcomes to the plaintiff(s) in any such action.” for further details.

The depositary bank will register and deliver the Sayona ADSs issuable in the merger and will be the holder of Sayona ordinary shares represented by the Sayona ADSs. Holders of Sayona ADSs will not be treated as shareholders of Sayona and will not have shareholder rights, but will only have Sayona ADS holder rights set forth in the deposit agreement.

In particular, except as described in the deposit agreement, Sayona ADS Holders will not able to exercise voting rights attaching to the Sayona ordinary shares represented by the Sayona ADSs on an individual basis. If Sayona asks the depositary bank to solicit voting instructions, holders of Sayona ADSs will have a right to instruct the depositary bank how to exercise the voting rights attaching to the Sayona ordinary shares represented by the Sayona ADSs. Otherwise, Sayona ADS Holders will not be able to exercise their right to vote unless they cancel their Sayona ADSs and withdraw the Sayona ordinary shares represented by Sayona ADSs. However, you may not know of the meeting sufficiently in advance to withdraw the Sayona ordinary shares. If Sayona asks for instructions from Sayona ADS Holders, the depositary bank will notify such holders of the upcoming vote and arrange to deliver Sayona’s voting materials to such holders and will try, as far as practical, to vote the Sayona ordinary shares represented by the Sayona ADSs as Sayona ADS Holders instruct. Sayona cannot assure you that you will receive voting materials in time to instruct the depositary bank to vote, and it is possible that holders of Sayona ADSs, including persons who hold their Sayona ADSs through brokers, dealers, or other third parties, will not have the opportunity to exercise a right to vote.

Additionally, Sayona ADS Holders will not have the same rights to receive dividends or other distributions as holders of Sayona ordinary shares. Subject to any rights or restrictions attached to any shares or class of shares, the directors of Sayona may determine that a dividend will be payable on Sayona ordinary shares and fix the amount, the time for payment and the method for payment (although Sayona has never declared or paid any cash dividends on Sayona ordinary shares and does not anticipate paying any cash dividends in the foreseeable future). Dividends and other distributions payable to shareholders of Sayona with respect to Sayona ordinary shares generally will be payable directly to them. Any dividends or distributions payable with respect to Sayona ordinary shares represented by Sayona ADSs will be paid to the depositary bank, which has agreed to pay to Sayona ADS Holders the cash dividends or other distributions it receives on shares or other deposited securities, after converting the currency it receives into U.S. dollars and deducting its fees and expenses. Before the depositary bank makes a distribution to a Sayona ADS Holder in respect of Sayona ADSs, it will also withhold any amounts in respect of taxes or other governmental charges. Additionally, if the exchange rate fluctuates during a time when the ADS depositary bank cannot convert the foreign currency, Sayona ADS Holders may lose some or all of the value of the distribution. Sayona ADS Holders will receive these distributions in proportion to

the number of Sayona ordinary shares their Sayona ADSs represent. In addition, there may be certain circumstances in which the depositary bank may not pay to Sayona ADS Holders the amounts distributed by Sayona as a dividend or distribution, for example, if it is unlawful or impractical to make a distribution available to any holders of Sayona ADSs.

For more information, see the section of this proxy statement/prospectus entitled “Description of Sayona American Depositary Shares” beginning on page 210.

Under the terms of the deposit agreement, the depositary bank is entitled to charge Sayona ADS Holders fees for various services, including for the issuance of the Sayona ADSs upon deposit of Sayona ordinary shares, cancellation of Sayona ADSs for withdrawal of Sayona ordinary shares, distributions of cash dividends or other cash distributions, distributions of Sayona ADS pursuant to share dividends or other share distributions, distributions of securities other than Sayona ADSs and annual service fees. For more information, see the section of this proxy statement/prospectus entitled “Description of Sayona American Depositary Shares—Deposit Agreement—Fees and Charges” beginning on page 212.

The deposit agreement governing Sayona ADSs provides that, to the fullest extent permitted by law, Sayona ADS holders (including purchasers of Sayona ADSs in secondary transactions) waive the right to a jury trial of any claim they may have against Sayona or the depositary bank arising out of or relating to Sayona ordinary shares, the Sayona ADSs or the deposit agreement, including any claim under the U.S. federal securities laws.

If Sayona or the depositary bank opposed a jury trial demand based on the waiver, the court would determine whether the waiver was enforceable based on the facts and circumstances of that case in accordance with the applicable state and federal law. To Sayona’s knowledge, the enforceability of a contractual pre-dispute jury trial waiver in connection with claims arising under the federal securities laws has not been finally adjudicated by the United States Supreme Court. However, Sayona believes that a contractual pre-dispute jury trial waiver provision is generally enforceable, including under the laws of the State of New York, which govern the deposit agreement, by a federal or state court in the State of New York, which has jurisdiction over matters arising under the deposit agreement. In determining whether to enforce a contractual pre-dispute jury trial waiver provision, courts will generally consider whether a party knowingly, intelligently and voluntarily waived the right to a jury trial. Sayona believes that this is the case with respect to the deposit agreement and the Sayona ADSs. It is advisable that you consult legal counsel regarding the jury trial waiver provision before entering into the deposit agreement.

If you or any other holders or owners of Sayona ADSs bring a claim against Sayona or the depositary bank in connection with matters arising under the deposit agreement or the Sayona ADSs, including claims under federal securities laws, you or such other holder or beneficial owner may not be entitled to a jury trial with respect to such claims, which may have the effect of limiting and discouraging lawsuits against Sayona or the depositary bank, lead to increased costs to bring a claim, limited access to information and other imbalances of resources between such holder and Sayona, or limit such holder’s ability to bring a claim in a judicial forum that such holder finds favorable. If a lawsuit is brought against Sayona or the depositary bank under the deposit agreement, it may be heard only by a judge or justice of the applicable trial court, which would be conducted according to different civil procedures and may result in different outcomes than a trial by jury would have had, including results that could be less favorable to the plaintiff(s) in any such action.

No condition, stipulation or provision of the deposit agreement or Sayona ADSs shall relieve Sayona or the depositary bank from their respective obligations to comply with the Securities Act and the Exchange Act nor serve as a waiver by any holder or owner of Sayona ADSs of compliance with the U.S. federal securities laws and the rules and regulations promulgated thereunder, inasmuch as those cannot be waived by any person.

Pursuant to the Sayona equity raise, Sayona issued 1,250,000,000 Sayona ordinary shares at the issue price of AU$0.032 (approximately $0.02, at the then-prevailing exchange rate) per Sayona ordinary share. In connection with the completion of the transaction, (i) Sayona expects to issue approximately 11,700,000,000 new Sayona ordinary shares (or 78,000,000 new Sayona ordinary shares if, prior to the completion of the transaction, Sayona effects the Sayona share consolidation) (including, in each case, Sayona ordinary shares represented by Sayona ADSs) as the merger consideration, (ii) certain Piedmont equity awards are required to be converted into equity awards of Sayona pursuant to the merger agreement and, (iii) in connection with the closing equity raise, Sayona expects to issue an additional 2,156,250,000 Sayona ordinary shares at the issue price of AU$0.032 (approximately $0.02, at the prevailing exchange rate as of June 2, 2025) per Sayona ordinary share (or 14,375,000 Sayona ordinary shares at the issue price of AU$4.80 (approximately $3.12, at the prevailing exchange rate as of June 2, 2025) per Sayona ordinary share if, prior to such issuance of Sayona ordinary shares, Sayona effects the Sayona share consolidation). Immediately after the effective time of the merger, the pre-merger Sayona shareholders, on the one hand, and the pre-merger holders of eligible shares of Piedmont common stock and Piedmont CDIs, on the other hand, will each own collectively approximately 50% of the ordinary shares of Sayona on a fully diluted basis (including the Sayona ordinary shares represented by the Sayona ADSs). In addition, Sayona ordinary shares or Sayona ADSs may be issued from time to time following the effective time to holders of Piedmont equity awards on the terms set forth in the merger agreement. See the section of this proxy statement/prospectus entitled “The Merger—Interests of Piedmont’s Directors and Executive Officers in the Merger” beginning on page 104 for a more detailed explanation.

Securities class actions and derivative lawsuits are often brought against companies that have entered into merger agreements. Even if the lawsuits are without merit, defending against these claims can result in substantial costs and divert management time and resources. Additionally, if a plaintiff is successful in obtaining an injunction prohibiting consummation of the transaction, then that injunction may delay or prevent the transaction from being completed.

The combined company may be exposed to increased litigation from holders of Sayona ADSs or Sayona ordinary shares, customers, suppliers, consumers and other third parties due to the combination of Sayona’s business and Piedmont’s business following the transaction. Such litigation may have an adverse impact on the combined company’s business and results of operations or may cause disruptions to the combined company’s operations.

Sayona’s success after the transaction will depend in part on its ability to retain key executives and other employees. Uncertainty about the effect of the transaction on Sayona and Piedmont employees may have an adverse effect on each of Sayona and Piedmont and consequently on the combined company. This uncertainty may impair, prior to the completion of the transaction, Sayona’s, Piedmont’s, and following the completion of the transaction, the combined company’s, ability to attract, retain and motivate personnel. Employee retention may be particularly challenging during the pendency of the transaction, as employees of Sayona and Piedmont may experience uncertainty about their future roles in the combined company.

Additionally, Piedmont’s officers and employees may hold shares of Piedmont common stock and/or certain equity awards, and, if the transaction is completed, these officers and employees may be entitled to the merger consideration in respect of such shares of Piedmont common stock and/or certain equity awards. Under agreements between Piedmont and certain of its employees, such employees could potentially resign from employment on or after the effective time, resulting in severance payments to such employees and accelerated vesting of their equity awards. These payments and accelerated vesting benefits, individually or in the aggregate, could make retention of Piedmont employees more difficult.

Furthermore, if employees of Sayona or Piedmont depart or are at risk of departing, including because of issues relating to the uncertainty and difficulty of integration, financial security or a desire not to become employees of the combined company, Sayona may have to incur significant costs in retaining such individuals or in identifying, hiring and retaining replacements for departing employees and may lose significant corporate knowledge, expertise and talent. As a result, the combined company’s ability to realize the anticipated benefits of the transaction may be materially and adversely affected. No assurance can be given that the combined company will be able to attract or retain employees to the same extent that Piedmont or Sayona has been able to attract or retain employees in the past.

The financial estimates set forth in the forecasts included under the section “The Merger—Certain Unaudited Prospective Financial Information” were based on assumptions of, and information available to, Piedmont’s management when prepared and these estimates and assumptions are subject to uncertainties, many of which are beyond Piedmont’s control and may not be realized. Many factors mentioned in this proxy statement/prospectus, including the risks outlined in this “Risk Factors” section and the events or circumstances described under “Cautionary Statement Regarding Forward-Looking Statements,” will be important in determining the combined company’s future results. As a result of these contingencies, actual future results may vary materially from the estimates. In view of these uncertainties, the inclusion of financial estimates in this proxy statement/prospectus is not and should not be viewed as a representation that the forecasted results will necessarily reflect actual future results.

The financial estimates set forth in the forecasts included under the section “The Merger—Certain Unaudited Prospective Financial Information” were not prepared with a view toward public disclosure, and such financial estimates were not prepared with a view toward compliance with published guidelines of any regulatory or professional body. Further, any forward-looking statement speaks only as of the date on which it is made, and Piedmont does not undertake any obligation, other than as required by applicable law, to update the financial estimates herein to reflect events or circumstances after the date those financial estimates were prepared or to reflect the occurrence of anticipated or unanticipated events or circumstances. The prospective financial information included in this document has been prepared by, and is the responsibility of, Piedmont’s management. None of PricewaterhouseCoopers LLP, Piedmont’s independent registered public accounting firm, Deloitte & Touche LLP, Ernst & Young, Sayona’s independent auditor, Moore Australia Audit (WA) or any other independent registered public accounting firm or independent auditor, have compiled, examined, or performed any procedures with respect to the prospective financial information contained herein, nor have they expressed any opinion or any other form of assurance on such information or its achievability, and assume no responsibility for, and disclaim any association with, the prospective financial information.

The reports of the independent registered public accounting firms incorporated by reference into this proxy statement/prospectus and the independent auditor included in this proxy statement/prospectus relate to the previously issued financial statements of either Piedmont or Sayona, respectively. Such reports do not extend to the prospective financial information and should not be read to do so.

See the section of this proxy statement/prospectus “The Merger—Certain Unaudited Prospective Financial Information” beginning on page 98.

Sayona ordinary shares are publicly traded on the ASX; and, upon completion of the transaction, Sayona expects to list the Sayona ADSs on the Nasdaq in the U.S. Sayona has submitted to, and discussed with, the Nasdaq its initial listing application with respect to the Sayona ADSs and expects to know the Nasdaq’s determination regarding such application prior to the Piedmont special meeting and the Sayona extraordinary general meeting. As a result of listing the Sayona ADSs on the Nasdaq in the U.S., Sayona may incur additional legal, accounting, insurance, and other expenses related to compliance with reporting requirements and certain other applicable requirements under U.S. law, as well as the listing rules of the Nasdaq. These expenses may increase to a greater extent when the combined company no longer qualifies as an EGC. The combined company’s management and other personnel may need to devote a substantial amount of time to these compliance initiatives, and, as a consequence, the combined company may need to add additional personnel and build its internal compliance infrastructure.

The combined company will need to have policies and procedures designed to provide reasonable assurance of its compliance with such requirements and listing rules. If, however, the combined company does not follow those procedures and policies, or they are not sufficient to prevent non-compliance, the combined company could be subject to liability, fines, and lawsuits. These requirements and listing rules are subject to varying interpretations, and as a result, their application in practice may evolve over time as new guidance is provided by regulatory and governing bodies. An investment by the combined company in resources to comply with evolving laws, regulations, rules and standards may result in increased administration and corporate overheads expenses and a diversion of management’s time and attention from growth and revenue-generating activities to compliance activities. If, notwithstanding the combined company’s efforts to comply with new laws, regulations, rules and standards, it fails to comply, regulatory or governing bodies may initiate legal proceedings against the combined company, and its business may be harmed.

Subject to the limitations and qualifications described in “The Merger—Material U.S. Federal Income Tax Consequences” below (including the discussion of Section 367(a) of the Code), it is intended that the merger qualify as a “reorganization” within the meaning of Section 368(a) of the Code, in which case a U.S. holder generally would recognize no gain or loss on the exchange of Piedmont common stock for Sayona securities. However, for the reasons described in “The Merger—Material U.S. Federal Income Tax Consequences” below, there is significant uncertainty concerning the U.S. federal income tax treatment of the exchange of Piedmont common stock for Sayona securities pursuant to the merger. Based on information available as of the date of this registration statement, it is currently expected that, even if the merger qualifies as a reorganization, the exchange of Piedmont common stock for Sayona securities pursuant to the merger will result in the recognition of gain (but not loss) for U.S. holders under Section 367(a) of the Code. U.S. holders are cautioned that the application of Section 367(a) of the Code to the merger is complex and depends on factors that cannot be determined until after the closing of the merger, as well as the interpretation of legal authorities, which are not entirely clear and subject to change. Additionally, there is limited guidance regarding the application of these requirements to facts similar to the merger. For a more complete discussion of the U.S. federal income tax consequences of the merger, including the application of Section 367(a) of the Code, see the section of this proxy statement/prospectus titled “The Merger—Material U.S. Federal Income Tax Consequences.”

You should read and consider the risk factors specific to Piedmont’s business and operations that will affect the combined company after completion of the transaction. These risks are described in Item 1A of Piedmont’s Annual Report on Form 10-K for the fiscal year ended December 31, 2024 and in Part II, Item 1A of Piedmont’s Quarterly Report on Form 10-Q for the quarter ended March 31, 2025, which are incorporated by reference into this proxy statement/prospectus, and in other documents that are incorporated by reference into this proxy statement/prospectus. See the section of this proxy statement/prospectus entitled “Where You Can Find Additional Information” beginning on page 296 for the location of information incorporated by reference into this proxy statement/prospectus.

Until the third quarter of 2023, Sayona had yet to realize any revenues from the sale of lithium, and Sayona’s operating cash flow needs have been financed primarily through issuances of common stock and not through cash flows derived from Sayona’s operations. As a result, Sayona has limited historical financial and operating information available to help you evaluate Sayona’s performance.

Although certain of Sayona’s projects have achieved (including North American Lithium), or may achieve, production, Sayona remains engaged in the business of exploring and developing mineral properties with the intention of locating additional economic deposits of minerals at its exploration and development properties.

Exploration and development of lithium resources are highly speculative in nature, and it is impossible to ensure that current and future exploration programs and/or feasibility studies on Sayona’s existing properties will establish reserves. Sayona has declared mineral reserves on its development stage properties; however, Sayona has yet to begin commercial extraction of minerals on these development stage properties. Accordingly, Sayona cannot assure you that it will realize profits in the medium to long term from its exploration and development activities. Further, Sayona cannot assure you that any of its development stage property interests can be commercially mined or that Sayona’s ongoing exploration programs will result in profitable commercial mining operations. The exploration and development of mineral deposits involve a high degree of financial risk over a significant period of time, which may or may not be reduced or eliminated through a combination of careful evaluation, experience, and skilled management. While discovery of ore-bearing deposits may result in substantial rewards, few properties that are explored are ultimately developed into producing mines. Major expenses may be required to construct mining and processing facilities and to establish additional reserves. The profitability of Sayona’s operations will be, in part, directly related to the cost and success of Sayona’s exploration and development programs, which may be affected by a number of factors. Additional expenditures are required to construct, complete, and install mining and processing facilities in those properties that are actually mined and developed.

Sayona’s exploration and development projects have no operating history upon which to base estimates of future operating costs and capital requirements. Exploration project items, such as any future estimates of reserves, metal recoveries, or cash operating costs will, to a large extent, be based upon the interpretation of geologic data, obtained from a limited number of drill holes and other sampling techniques as well as future feasibility studies. Actual operating costs and economic returns of any and all exploration projects may materially differ from the costs and returns estimated, and accordingly, Sayona’s financial condition, results of operations, and cash flows may be negatively affected.

Sayona cannot assure you that its exploration programs will identify economically extractable mineralization, nor can Sayona assure you about the quantity or grade of any mineralization Sayona seeks to extract. Sayona’s exploration prospects may not contain any reserves and any funds spent on evaluation and exploration may be lost. Even for the mineral reserves Sayona has reported for its properties, any quantity or grade of reserves Sayona indicates must be considered as estimates only until such reserves are actually mined. Sayona does not know with certainty that economically recoverable lithium exists on its exploration or development properties. In addition, the quantity of any reserves may vary depending on commodity prices. Any material change in the quantity or grade of reserves may affect the economic viability of Sayona’s exploration or development properties.

Sayona’s mineral reserve figures are primarily estimates and are not guarantees that Sayona will recover the indicated quantities of these minerals. You are cautioned not to place undue reliance on estimates of reserves (or resource estimates or exploration targets). Reserves are estimates made by Sayona’s professional technical personnel of the amount of minerals that they believe could be economically and legally extracted or produced at the time of the reserve determination. No assurance can be given that the estimated amount of mineral or the indicated level of recovery of these minerals will be realized. Reserve and resource estimation is an interpretive process based upon available data and various assumptions. Sayona’s reserve and resource estimates may change. Reserves are valued based on estimates of costs and mineral prices, which may not be consistent among Sayona’s properties or across the industry. The estimated quantities and economic value of mineral reserves may be adversely affected by:

Furthermore, short-term operating factors relating to Sayona’s mineral reserves, such as the need to sequentially develop orebodies and the processing of new or different ore grades, may adversely affect Sayona’s cash flow.

If the price of lithium declines substantially below the levels used to calculate reserves for an extended period, Sayona could experience:

Additionally, reserve estimates are subject to further development and preproduction drilling, resource estimates and exploration targets are subject to further exploration and development, and are, therefore, subject to considerable uncertainty. Sayona cannot be certain that any part or parts of resources or exploration targets will ever be confirmed or converted into reserves as defined by the SEC.

Sayona’s level of profitability, if any, in future years will depend to a great degree on lithium prices and whether Sayona’s exploration-stage properties can be brought into production. Exploration and development of lithium resources are highly speculative in nature, and it is impossible to ensure that current and future exploration programs and/or feasibility studies on Sayona’s existing properties will establish reserves. Whether it will be economically feasible to extract lithium depends on a number of factors, including: the particular attributes of the deposit such as size, grade, and proximity to infrastructure; lithium prices; mining, processing and transportation costs; the willingness of lenders and investors to provide project financing; labor costs and possible labor strikes; and governmental regulations, including, without limitation, regulations related to prices, taxes, royalties, land tenure, permitting, land use, importing and exporting materials, foreign exchange, environmental protection, local community issues, employment, unavailability of skilled labor, worker safety, transportation, and reclamation and closure obligations. Sayona could be adversely affected by a failure to complete its plant construction projects on time or on budget, and a substantial delay in the progress of construction due to adverse weather, work stoppages, shortages of materials, non-issuances of permits, nonperformance of suppliers or contractors, or other factors could result in a material increase in the overall cost of such projects. The exact effect of these factors cannot be accurately predicted, but the combination of these factors may result in Sayona receiving an inadequate return on invested capital. In addition, Sayona is subject to the risks normally encountered in the mining industry, such as:

The nature of these risks is such that liabilities could exceed any applicable insurance policy limits or could be excluded from coverage. There are also risks against which Sayona cannot insure or Sayona may elect not to insure. The potential costs, which could be associated with any liabilities not covered by insurance or in excess of insurance coverage, or compliance with applicable laws and regulations may cause substantial delays and require significant capital outlays, adversely affecting Sayona’s future earnings, competitive position, and potentially Sayona’s financial viability.

Moreover, from time to time, Sayona’s tenements, or tenements Sayona has a legal or beneficial interest in, may be subject to access restrictions. These may relate to the freehold owner of the land on which the tenements are located, or the rights of indigenous people. In those circumstances, Sayona may have to resolve access arrangements under the relevant regime prior to entering upon the land to carry out activities or developing a mine on the tenements. Access arrangements may be subject to the provision of monetary compensation, compensation for damage to land and restoration of the land. There can be no guarantee that applications or access arrangements will be resolved in a timely fashion, in Sayona’s favor, or in a manner that is commercially viable for Sayona. Sayona’s inability to resolve access issues on satisfactory terms, may impact its operations, and particularly its exploration program. If access issues are not resolved satisfactorily, this may impact Sayona’s business, results of operations, and financial condition.

The prices of lithium and lithium byproducts may fluctuate widely and are affected by numerous factors beyond Sayona’s control, including international, economic, and political trends, expectations of inflation, currency exchange fluctuations, interest rates, imposition of tariffs or other duties, global and regional consumptive patterns, speculative activities, increased production due to new extraction developments and improved extraction and production methods and technological changes in the markets for the end products. The effect of these factors on the prices of lithium and lithium byproducts, and therefore the economic viability of any of Sayona’s exploration, development, and operational properties, cannot be accurately predicted and could have dramatic effects on the results of Sayona’s operations and Sayona’s ability to execute its business plan. See, also “—Recent tariff announcements and other developments in international trade policies and regulations.”

New production of lithium hydroxide or lithium carbonate from current or new competitors in the lithium markets could adversely affect prices. In recent years, new and existing competitors have increased the supply of lithium spodumene concentrate, lithium hydroxide and lithium carbonate, which has affected pricing. Further production increases could negatively affect prices. There is limited information on the status of new lithium hydroxide, lithium spodumene and lithium carbonate production capacity expansion projects being developed by current and potential competitors and, as such, Sayona cannot make accurate projections regarding the capacities of possible new entrants into the market and the dates on which they could become operational. If these potential projects are completed in the short term, they could adversely affect market lithium prices, thereby resulting in a material adverse effect on the economic feasibility of extracting any mineralization Sayona discovers and reducing or eliminating any reserves Sayona identifies.

Sayona may not be able to effectively mitigate pricing risks for its products. Depressed pricing for Sayona’s products will negatively affect the level of revenues expected to be generated by Sayona, which, in turn, could affect Sayona’s value, share price and the potential value of Sayona’s assets. There can be no assurance that the price of lithium products will be such that it can be produced at a profit.

Sayona’s ability to recover carrying values of Sayona’s assets, acquire additional lithium projects, and continue with exploration, development, commissioning, and mining, ultimately depends on Sayona’s ability to

continue to generate revenues, achieve and maintain profitability, and generate positive cash flow from its operations. The economic viability of Sayona’s future mining activities has many risks and uncertainties including:

Sayona is concurrently overseeing the advancement of several major lithium projects, including Authier Lithium and Moblan Lithium, which are in the development stage, and North American Lithium, which has been a producing project since March 2023. Work to advance these projects requires the dedication of considerable time and resources by Sayona and its management team. The advancement of several major resource projects concurrently brings with it the associated risk of strains on managerial, human, and other resources. Sayona’s ability to successfully manage each of these processes will depend on a number of factors, including its ability to manage competing demands on time and other resources, financial or otherwise, and successfully retain personnel and recruit new personnel to support Sayona’s growth and the advancement of both its operations and projects.

Sayona’s plan is to ultimately produce battery-grade lithium hydroxide from spodumene concentrate using a number of processes commonly used in the lithium industry today. Sayona may encounter difficulties or unforeseen expenditures in integrating new, unproven technologies.

It is common for a new mining operation to experience unexpected costs, problems, and delays during construction, commissioning, and mine start-up. Most mining projects suffer delays during these periods due to numerous factors, including the factors listed above. Any of these factors could result in changes to economic returns or cash flow estimates of the project or have other negative impacts on Sayona’s financial position. There is no assurance that Sayona’s exploration and development projects will commence commercial production on schedule, or at all, or will result in profitable mining operations. If Sayona is unable to develop its projects into a commercial operating mine, its business and financial condition will be materially adversely affected. Moreover, even if the feasibility study continues to support a commercially viable project, there are many additional factors that could impact the project’s development, including terms and availability of financing, cost overruns, litigation or administrative appeals concerning the project, delays in development, and any delays in permitting or permitting changes, among other factors.

Sayona’s future mining activities may change as a result of any one or more of these risks and uncertainties. Sayona cannot assure you that any ore body from which it extracts mineralized materials will result in achieving and maintaining profitability and developing positive cash flows.

Sayona may encounter difficulty entering into or fulfilling offtake and other sale agreements for its product. Sayona may fail to deliver the product required by such agreements or may experience production costs in excess of the price to be paid to Sayona under such agreements. Failure to meet these specifications could result in price adjustments, the rejection of deliveries, or termination of the contracts. Sayona’s supply agreements contain force majeure provisions allowing temporary suspension of performance by Sayona or the customer

during specified events beyond the control of the affected party. As a result of these issues, Sayona may not achieve the revenue or profit Sayona expects to achieve from its offtake and other sale agreements. As of the date of this proxy statement/prospectus, Sayona has entered into two long-term offtake agreements and one medium-term sales agreement for its lithium product.

On January 9, 2021, Sayona Québec entered into a spodumene concentrate purchase agreement with Piedmont Lithium Carolinas, Inc., an affiliate of Piedmont, to provide spodumene concentrate from North American Lithium in Québec. The agreement commits Sayona Québec to sell to Piedmont Lithium Carolinas, Inc. the greater of 50% of North American Lithium’s annual production or 113,000 dry metric tons (“dmt”) of spodumene concentrate. The term of the agreement relates to the life of mine of Sayona Québec’s open pit mine and concentrator located near Val-d’ Or, Québec, and pricing is determined by a market-based mechanism, subject to a guaranteed price minimum and guaranteed price maximum.

On October 15, 2021, 9450-5567 Quebec Inc., a wholly owned subsidiary of Sayona, entered into an offtake agreement with Lithium Royalty Corp. in respect of the Moblan Lithium project. The agreement commits 9450-5567 Quebec Inc. to sell to Lithium Royalty Corp. an amount of spodumene concentrate or lithium concentrate that is equal to 10% of 9450-5567 Quebec Inc.’s 60% interest in such concentrate produced from the Moblan Lithium project (relating to its 60% participating interest in the Moblan Lithium project). The term of the agreement relates to the life of mine of the Moblan Lithium project, and pricing is determined by a market-based mechanism.

On August 22, 2024 (effective as of June 21, 2024), Sayona and North American Lithium Inc., on the one hand, and an international trading company, on the other hand, entered into a contract note to provide lithium spodumene concentrate from NAL in Québec. Pricing under the agreement is determined by a market-based mechanism.

Sayona’s business, results of operations, and financial condition may be materially and adversely affected if Sayona is unable to enter into similar agreements with other buyers, deliver the products required by such agreements, or incur costs in excess of the price set forth in such agreements.

Sayona has incurred, and may in the future incur, operating and investing net cash outflows, including those associated with maintaining and acquiring exploration properties, undertaking ongoing exploration activities, and the development, for example, of the Authier Lithium and Moblan Lithium projects. Sayona relies on access to capital markets as a source of funding, in addition to revenues generated from production at North American Lithium, for its capital and operating requirements. Sayona will require additional capital to meet its liquidity needs related to expenses for its various corporate activities, including costs related to its status as a publicly traded company, funding of its ongoing operations, exploring and defining lithium mineralization, and establishing any future mining operations. Sayona cannot assure you that such additional funding will be available to it on satisfactory terms, or at all.

To finance Sayona’s future ongoing operations and future capital needs, Sayona may require additional funds through the issuance of additional equity or debt securities. Under Australian law, Sayona does not have a limit on the authorized share capital that may be issued. Depending on the type and terms of any financing Sayona pursues, shareholders’ rights and the value of their investment in Sayona ordinary shares or Sayona ADSs could be reduced. Any additional equity financing will dilute shareholdings. If the issuance of new securities results in diminished rights to holders of Sayona ordinary shares or Sayona ADSs, the market price of Sayona ordinary shares or Sayona ADSs could be negatively impacted. For example, pursuant to the Sayona equity raise, Sayona issued 1,250,000,000 Sayona ordinary shares at the issue price of AU$0.032 (approximately $0.02, at the then-prevailing exchange rate) per Sayona ordinary share. In connection with the completion of the transaction, (i) Sayona expects to issue approximately 11,700,000,000 new Sayona ordinary shares (or 78,000,000 new Sayona ordinary shares if, prior to the completion of the transaction, Sayona effects the Sayona share consolidation) (including Sayona ordinary shares represented by Sayona ADSs) as the merger consideration, (ii) certain Piedmont equity awards are required to be converted into equity awards of Sayona pursuant to the merger agreement and, (iii) in connection with the closing equity raise, Sayona expects to issue an additional

2,156,250,000 Sayona ordinary shares at the issue price of AU$0.032 (approximately $0.02, at the prevailing exchange rate as of June 2, 2025) per Sayona ordinary share (or 14,375,000 Sayona ordinary shares at the issue price of AU$4.80 (approximately $3.12, at the prevailing exchange rate as of June 2, 2025) per Sayona ordinary share if, prior to such issuance of Sayona ordinary shares, Sayona effects the Sayona share consolidation).

New or additional debt financing, if available, may involve restrictions on financing and operating activities. In addition, if Sayona issues secured debt securities, the holders of the secured debt would have a claim to Sayona’s assets that would be prior to the rights of Sayona shareholders until the debt is paid. Interest on such debt securities would increase costs and negatively impact Sayona’s operating results.

If Sayona is unable to obtain additional financing, as needed, at competitive rates, its ability to fund its current operations and implement its business plan and strategy will be affected. These circumstances may require Sayona to reduce the scope of its operations and scale back its exploration, development and mining programs. There is, however, no guarantee that Sayona will be able to secure any additional funding or be able to secure funding to provide it with sufficient funds to meet its objectives, which may adversely affect Sayona’s business and financial position. Certain market disruptions may increase Sayona’s cost of borrowing or affect Sayona’s ability to access one or more financial markets. Such market disruptions could result from, but are not limited to:

Future growth may place strains on Sayona’s financial, technical, operational, and administrative resources and cause Sayona to rely more on project partners and independent contractors, thus, potentially adversely affecting its financial position and results of operations. Sayona’s ability to grow will depend on a number of factors, including:

Sayona may not be successful in upgrading its technical, operational, and administrative resources or increasing its internal resources sufficiently to provide certain services currently provided by third parties. Sayona’s inability to achieve or manage growth may materially and adversely affect Sayona’s business, results of operations, and financial condition.

As part of Sayona’s business strategy, Sayona may pursue additional acquisitions of or mergers with complementary businesses, including the merger with Piedmont, or assets or seek to enter into joint ventures. Sayona may pursue strategic alliances in an effort to leverage its existing operations and industry experience, increase its product offerings, expand its distribution, and make investments in other companies.

The success of any acquisitions, mergers, joint ventures, strategic alliances, or investments, including Sayona’s Authier Lithium, North American Lithium and Moblan Lithium investments, will depend on Sayona’s ability to identify, negotiate, complete and, in the case of mergers, including the merger with Piedmont, integrate those transactions and, if necessary, obtain satisfactory debt or equity financing to fund those transactions. Sayona may not realize the anticipated benefits of any acquisition, merger, including the merger with Piedmont, joint venture, strategic alliance or investment. Sayona may not be able to integrate acquired or merged businesses successfully into its existing business, maintain the key business relationships of businesses Sayona’s acquires or merges with, or retain key personnel of an acquired or merged business, in each case, including the merger with Piedmont. Sayona could assume unknown or contingent liabilities or incur unanticipated expenses. Integration of acquired or merged companies or businesses, including Piedmont, also may require management resources that otherwise would be available for ongoing development of Sayona’s existing business. Any acquisitions or mergers, including the merger with Piedmont, or investments made by Sayona could result in significant write-offs or the incurrence of debt and contingent liabilities, any of which could harm Sayona’s operating results. If Sayona chooses to issue equity as consideration for any acquisition or merger, including the merger with Piedmont, Sayona shareholders or Sayona ADS holders may experience dilution.

The responsibility of overseeing the day-to-day operations and the strategic management of Sayona’s business depends substantially on Sayona’s Executive KMP and other key personnel, including those with specialized technical skills, in Canada and Australia. Loss of any such personnel may have an adverse effect on Sayona’s performance. The success of Sayona’s operations will depend upon numerous factors, many of which, in part, are beyond Sayona’s control, including Sayona’s ability to attract and retain additional key personnel, including those with technical skills, across various operations within Sayona’s business. Certain areas in which Sayona operates, including Canada, are highly competitive and competition for qualified personnel is significant. Sayona may be unable to hire suitable field personnel for its technical team or there may be periods of time where a particular position remains vacant while a suitable replacement is identified and appointed. Sayona may not be successful in attracting and retaining the personnel required to grow and operate its business profitably.

Sayona may become involved in, named as a party to, or be the subject of various legal proceedings, including regulatory proceedings, tax proceedings, and legal actions related to personal injuries, property damage, property taxes, land rights, the environment, merger and acquisition activity (including the merger with Piedmont), capital raisings and contract disputes.

The outcome of outstanding, pending or future proceedings cannot be predicted with certainty and may be determined adversely to Sayona and as a result, could have a material adverse effect on Sayona’s assets, liabilities, business, financial condition, results of operations or the market price of Sayona ordinary shares or Sayona ADSs. Even if Sayona prevails in any such legal proceeding, the proceedings could be costly, time-consuming, and may divert the attention of management and key personnel from Sayona’s business operations, which could adversely affect Sayona’s financial condition.

Many of the mining claims of which Sayona has an interest are subject to ongoing royalty obligations. The amount of the royalties payable in respect of a claim may have an impact on the economic viability of that claim, depending on various factors such as commodity prices and prevailing economic conditions. The amount of royalties payable may impact the profitability of Sayona and consequently impact on the value of Sayona’s ordinary shares or Sayona ADSs.

The ownership, interests in and title to mining claims and concessions are often uncertain and may be contested. Sayona may not have, or may not be able to obtain, all necessary rights to explore and develop a property. Although Sayona has taken reasonable measures to ensure proper title to Sayona’s properties, there is no guarantee that title to any of Sayona’s properties will not be challenged or impugned. Sayona’s mineral properties may be subject to prior unregistered agreements, transfers, or claims, and title may be affected by, among other things, undetected defects. Sayona may incur significant costs related to defending the title to Sayona’s properties. A successful claim contesting Sayona’s title to a property may cause Sayona to compensate other persons or perhaps reduce Sayona’s interest in the affected property or lose Sayona’s rights to explore and develop that property. This could result in Sayona not being compensated for its prior expenditures related to the property or to realize future gains from mining and selling those minerals. In any such case, the investigation and resolution of title issues would divert Sayona’s management’s time from ongoing exploration and, if warranted, development programs. Any impairment or defect in title could negatively affect us.

Some of Sayona’s Non-Executive Directors currently serve as directors of other companies involved in natural resource exploration, development, and production, and any of Sayona’s Non-Executive Directors may serve in such positions in the future. As of the date of this proxy statement/prospectus, none of Sayona’s directors or officers serves as an officer or director of a lithium exploration, development, or producing company nor possess a conflict of interests with Sayona’s business, other than Mr. James Brown and Mr. Allan Buckler who both serve as directors of Morella Corporation Limited (ASX:1MC). However, there exists the possibility that they may be in a position of conflict of interest in the future. Any decision made by such persons involving Sayona will be made in accordance with their duties and obligations to deal fairly and in good faith with Sayona and such other companies. In addition, any such directors and officers will declare, and refrain from voting on, any matter in which such directors and officers may have a material interest.

To manage Sayona’s growth and support its future operations, Sayona will periodically upgrade its operational and financial systems, processes and procedures. This requires management time and may result in significant expense. Sayona cannot be certain that it will institute in a timely or efficient manner, or at all, the improvements to its managerial, operational, governance, information and communication technology and financial systems and procedures necessary to support its anticipated increased levels of operations. Problems associated with, or disruptions resulting from, any improvement or expansion of Sayona’s operational and financial systems could adversely affect its relationships with suppliers and customers, inhibit Sayona’s ability to expand or take advantage of market opportunities, cause harm to Sayona’s reputation, result in errors in Sayona’s financial and other reporting, and adversely affect Sayona’s ability to maintain an effective internal control environment and meet Sayona’s governance and external reporting obligations, any of which could harm Sayona’s business and operating results and affect the price of Sayona ordinary shares or Sayona ADSs.

Three customers accounted for approximately 100% of Sayona’s sales during the fiscal year ended June 30, 2024. The company’s future prospects may depend on the continued business of a limited number of key customers and on Sayona’s continued status as a qualified supplier to such customers. The company cannot

guarantee that these key customers will continue to buy products from Sayona at current levels. The loss of a key customer could have a material adverse effect on Sayona’s business, financial condition, and results of operations. See “—Sayona’s long-term success depends on Sayona’s ability to enter into and deliver product under offtake and other purchase agreements.”

If any of Sayona’s facilities or the facilities of Sayona’s suppliers, third-party service providers, or customers is affected by natural disasters, such as earthquakes, floods, fires, power shortages or outages, public health crises (such as pandemics and epidemics), political crises (such as terrorism, war, political instability or other conflict), or other events outside of Sayona’s control, Sayona’s operations or financial results could suffer. It is possible that these occurrences may impact Sayona’s operations even if they occur outside of the jurisdictions where Sayona operates. Sayona only has a limited ability to insure against these risks. Any of these events could materially and adversely impact Sayona in a number of ways, including through decreased production, increased costs, decreased demand for Sayona’s products due to reduced economic activity or other factors, or the failure by counterparties to perform under contracts or similar arrangements.

Global credit and financial markets have experienced extreme disruptions at various points over the last few decades, characterized by diminished liquidity and credit availability, declines in consumer confidence, declines in economic growth, increases in unemployment rates, and uncertainty about economic stability. If another such disruption in credit and financial markets and deterioration of confidence in economic conditions occurs, Sayona’s business may be adversely affected. If the equity and credit markets were to deteriorate significantly in the future, it may make any necessary debt or equity financing more difficult to complete, more costly, and more dilutive. Failure to secure any necessary financing in a timely manner and on favorable terms, or to secure any such financing at all, could have a material adverse effect on Sayona’s growth strategy, financial performance, and share price and could require Sayona to delay or abandon development or commercialization plans. In addition, there is a risk that one or more of Sayona’s service providers, manufacturers, or other partners would not survive or be able to meet their commitments to Sayona under such circumstances, which could directly affect Sayona’s ability to attain Sayona’s operating goals on schedule and on budget.

Furthermore, geopolitical instability and uncertainty, such as acts of terrorism, international hostilities, labor strikes, civil wars and geopolitical tensions, such as the ongoing conflicts between Russia and Ukraine, conflict in the Middle East, and increasing tensions between China and Taiwan, and government actions implemented as a result thereof, may negatively impact the global economy and Sayona’s operations, financial performance and financial position. These occurrences and conflicts have already resulted in and may continue to result in sanctions (including with respect to China), embargoes, regional instability, energy shortages, geopolitical shifts and adverse effects on macroeconomic conditions, security conditions, challenges to currency exchange rates and financial markets, and global shipping constraints, all of which may be detrimental to Sayona’s operations, financial performance and financial position. Sayona only has a limited ability to insure against these risks.

Sayona’s operations depend on effective and secure information technology systems. Threats to information technology systems, such as cyberattacks and cyber incidents, continue to increase. Cybersecurity risks include, but are not limited to, malicious software, attempts to gain unauthorized access to Sayona’s data and the unauthorized release, corruption or loss of Sayona’s data and personal information, as well as interruptions in communication and operations.

It is possible that Sayona’s business, financial, and other systems could be compromised, which could go unnoticed for a prolonged period of time. Sayona has not experienced a material breach of its information technologies. Nevertheless, Sayona continues to take steps to mitigate these risks by employing a variety of measures, including employee training, technical security controls, and maintenance of backup and protective systems. Despite these mitigation efforts, cybersecurity attacks and other threats exist and continue to increase, any of which could have a material adverse effect on Sayona’s business, results of operations, financial condition, and cash flows.

Breaches of Sayona’s security measures or the accidental loss, inadvertent disclosure, or unapproved dissemination of proprietary information or sensitive or confidential information about Sayona, its employees, its vendors, or its customers, could result in litigation, violations of various data privacy regulations in some jurisdictions, and could also potentially result in liability to Sayona. This could damage Sayona’s reputation, or otherwise harm its business, financial condition, or results of operations.

Sayona conducts operations through various subsidiaries in countries throughout the world. Tax laws, regulations and treaties are highly complex and subject to interpretation. Consequently, Sayona is subject to changing tax laws, regulations and treaties in and between the countries in which it operates. Sayona’s income tax expense is based upon its interpretation of the tax laws in effect in various countries at the time that the expense was incurred. A change in these tax laws, regulations or treaties, or in the valuation of its deferred tax assets, which is beyond its control, could result in a materially higher tax expense or a higher effective tax rate on its worldwide earnings.

Sayona’s tax returns are subject to review and examination. Sayona does not recognize the benefit of income tax positions it believes are more likely than not to be disallowed upon challenge by a tax authority. If any tax authority successfully challenges Sayona’s tax positions, or if Sayona loses a material tax dispute in any country, its taxes on its worldwide earnings could increase substantially and its earnings and cash flows could be materially adversely affected.

Sayona is a mining company incorporated and headquartered in Australia with operations in Canada and Australia and international customers. In addition, following the consummation of the merger, Sayona will acquire Piedmont’s customer base, which includes customers purchasing lithium spodumene concentrate in the U.S. As such, Sayona is and will be sensitive to changes in international trade policies and regulations.

During 2025, the U.S. President has announced, implemented or modified various tariffs on goods imported to the United States, including, among others, automobiles (and parts thereof), steel and aluminum, from countries such as Australia, Canada, Mexico and China, among others. For example, on April 2, 2025, the U.S. President announced a new universal baseline tariff of 10%, plus an additional country-specific tariff for select trading partners, on all U.S. imports, in each case, subject to certain exemptions. The universal baseline tariffs took effect on April 5, 2025. The additional country-specific tariffs were expected to take effect on April 9, 2025; however, on April 9, 2025, the U.S. President delayed effectiveness for 90 days, except with respect to China, for which the U.S. President also increased the country-specific tariff. In response, certain countries impacted by the tariffs that have taken effect, or been announced, during 2025 announced or implemented countermeasures involving tariffs on goods imported from the United States. On May 12, 2025, the governments of the United States and China announced reductions and suspensions of certain tariffs on goods traded between the two countries.

Sayona is unable to predict the ultimate result or duration of any new tariffs, or changes to existing tariffs, imposed by the U.S. or any other country, or tariff countermeasures that may be taken by any country.

Imposition of tariffs or other trade barriers and changes in trading policies, potential retaliatory measures, or uncertainties in international trade policies and regulations may adversely impact Sayona’s operations, particularly given Sayona’s presence across multiple jurisdictions. Such tariffs, if applied to the lithium spodumene concentrate Sayona produces, or equipment Sayona may need to operate its business, could adversely affect Sayona’s revenues (including revenue generated from sales of Canadian lithium spodumene concentrate to the U.S.) and costs, the economics of Sayona’s projects and Sayona’s ability to develop those projects successfully. Recent tariff actions have resulted in market uncertainty and volatility and concerns over inflation, recession and slowing growth. Continued market uncertainty or volatility, or any broader economic challenges resulting from adverse developments in internal trade policies, could adversely affect the price of Sayona ordinary shares and Sayona ADSs and Sayona’s ability to raise additional capital.

Sayona is required to obtain, maintain and renew governmental licenses, permits, authorizations, concessions and other approvals for its exploration and development activities in relevant jurisdictions, including Canada and Australia, and prior to mining any mineralization Sayona discovers, Sayona will be required to obtain additional governmental licenses, leases permits, authorizations, concessions and other approvals that Sayona does not currently possess. Such items are related to the laws and regulations that govern prospecting, mining, production, exports, taxes, labor standards, occupational health, waste disposal, toxic substances, land use, surface rights, environmental protection, safety and other matters.

Obtaining, maintaining and renewing any of these items is a complex, time-consuming, and uncertain process involving numerous jurisdictions, public hearings, and possibly costly undertakings. The timeliness and success of permitting efforts are contingent upon many variables not within Sayona’s control, including the interpretation of approval requirements administered by the applicable governmental authority.

Sayona may not be able to obtain, maintain or renew licenses, leases, permits, authorizations, concessions and other approvals that are necessary to conduct its planned operations, or Sayona may discover that the cost and time required to obtain, maintain or renew such licenses, permits, authorizations, concessions and other approvals exceeds its expectations. Any unexpected delays, costs or conditions associated with the governmental approval process could delay Sayona’s planned exploration, development, and mining operations, which in turn could materially adversely affect Sayona’s prospects, revenues, and profitability. In addition, Sayona’s prospects may be adversely affected by the revocation or suspension of licenses, permits, authorizations, concessions and other approvals or by changes in the scope or conditions to use of any licenses, permits, authorizations, concessions and other approvals obtained.

Additionally, new laws or regulations may be enacted, or existing laws and regulations could be applied in a manner, which could limit or curtail Sayona’s activities. The ultimate development or operation of Sayona’s assets may also be negatively impacted. Any inability to conduct Sayona’s mining operations or development activities pursuant to applicable required authorizations could materially reduce Sayona’s production and cash flow.

Private parties, such as environmental activist organizations or local community groups, frequently attempt to intervene in the permitting process to persuade regulators to deny necessary permits or seek to overturn permits that have been issued. These third-party actions can materially increase the costs, cause delays in the permitting process, and could cause Sayona to not proceed with the development or operation of a property. Sayona’s ability to successfully obtain key permits and approvals to explore for, develop, operate, and expand operations will likely depend on its ability to undertake such activities in a manner consistent with the creation of social and economic benefits in the surrounding communities, which may or may not be required by law. Sayona’s ability to obtain permits and approvals and to successfully operate in particular communities may be adversely affected by real or perceived detrimental events associated with Sayona’s activities.

Environmental regulations mandate, among other things, the maintenance of air and water quality standards, land development, and land reclamation/rehabilitation, and set forth limitations on the generation, transportation, storage and disposal of solid and hazardous waste. Environmental legislation is evolving in a manner that may require stricter standards and enforcement, increased fines and penalties for non-compliance, more stringent environmental assessments of proposed projects, and a heightened degree of responsibility for mining companies and their officers, directors, and employees. In connection with Sayona’s current exploration, development or production activities or in connection with Sayona’s prior mining operations, Sayona may incur environmental costs that could have a material adverse effect on the financial condition and results of Sayona’s operations. Any failure to remedy an environmental problem could require Sayona to suspend operations or enter into interim compliance measures pending completion of the required remedy.

Moreover, governmental authorities and private parties may bring lawsuits based upon damage to property and injury to persons resulting from the environmental, health, and safety impacts of prior and current operations, including operations conducted by other mining companies many years ago at sites located on properties that Sayona currently owns or formerly owned. These lawsuits could lead to the imposition of substantial fines, remediation costs, penalties, and other civil and criminal sanctions as well as reputational harm, including damage to Sayona’s relationships with customers, suppliers, investors, governments, or other stakeholders. Such laws, regulations, enforcement, or private claims may have a material adverse effect on Sayona’s financial condition, results of operations, or cash flows.

Lithium and its derivatives are preferred raw materials for certain industrial applications, such as rechargeable batteries. For example, current and future high energy density batteries for use in electric vehicles will rely on lithium compounds as a critical input. The pace of advancements in current battery technologies, development and adoption of new battery technologies that rely on inputs other than lithium compounds, or a delay in the development and adoption of future high nickel battery technologies that utilize lithium hydroxide could significantly impact Sayona’s prospects and future revenues. Many materials and technologies are being researched and developed with the goal of making batteries lighter, more efficient, faster charging, and less expensive, some of which could be less reliant on lithium hydroxide or other lithium compounds. Some of these technologies, such as commercialized battery technologies that use no, or significantly less, lithium compounds, could be successful and could adversely affect demand for lithium batteries in personal electronics, electric and hybrid vehicles, and other applications. Sayona cannot predict which new technologies may ultimately prove to be commercially viable and on what time horizon. In addition, alternatives to industrial applications dependent on lithium compounds may become more economically attractive as global commodity prices shift. Any of these events could adversely affect demand for and market prices of lithium, thereby resulting in a material adverse effect on the economic feasibility of extracting any mineralization Sayona discovers and reducing or eliminating any reserves Sayona identifies.

Sayona is one of a number of producers of performance lithium compounds that are a critical input in current and next-generation, high energy density batteries used in electric vehicle applications. Sayona’s growth is dependent upon the continued adoption of electric vehicles by consumers. If the market for electric vehicles does not develop as Sayona expects, or develops more slowly than Sayona expects, Sayona’s business, prospects, financial condition, and results of operations will be affected. The market for electric vehicles is relatively new, rapidly evolving, and could be affected by numerous external factors, such as:

Climate change could have an adverse impact on Sayona’s operations. The potential physical impacts of climate change on Sayona’s operations are highly uncertain and would be particular to the circumstances affecting each of Sayona’s projects. These may include changing average temperatures, changes in rainfall, snow

and storm patterns and intensities, water shortages, changing sea levels and other severe weather events. These changes in climate could have a material adverse impact on the cost of development or production for Sayona’s projects and adversely affect its operations and financial performance.

Regulations and pending legislation governing issues involving climate change and climate change reporting could result in increased operating costs, which could have a material adverse effect on Sayona’s business. A number of governments or governmental bodies have introduced or are contemplating regulatory changes in response to climate change and its potential impacts. Legislation and increased regulation regarding climate change could impose significant costs on Sayona and its suppliers, including costs related to increased energy requirements, capital equipment, environmental monitoring and reporting, and other costs to comply with such regulations. Any adopted climate change regulations could also negatively impact Sayona’s ability to compete with companies situated in areas not subject to such regulations. Given the emotion, political significance, and uncertainty around the impact of climate change and how it should be dealt with, Sayona cannot predict how legislation and regulation will affect its operating performance, ability to compete, and financial condition. Furthermore, even without such regulation, increased awareness and any adverse publicity in the global marketplace about the potential impacts of climate change as it relates Sayona or other companies in the natural resources industry could harm Sayona’s reputation.

Mining operations are subject to extensive and complex laws and regulations governing worker health and safety and failure to comply with applicable legal requirements can result in substantial penalties and may adversely impact Sayona’s operations, reputation, financial performance and financial position. Regardless of how carefully Sayona undertakes it operations, mining and exploration operations carry an inherent risk of liability and, as such, these risks cannot be eliminated. Future changes in applicable laws, regulations, permits and approvals or changes in their enforcement or regulatory interpretation could substantially increase costs to achieve compliance, lead to the revocation of existing or future exploration or mining rights or otherwise have an adverse impact on Sayona’s results of operations and financial position.

In addition to potential government restrictions and regulatory fines, penalties or sanctions, Sayona’s ability to operate (including the effect of any impact on its workforce) and thus, Sayona’s results of operations and its financial position (including because of potential related fines and sanctions), could be adversely affected by accidents, injuries, fatalities or events detrimental (or perceived to be detrimental) to the health and safety of Sayona’s employees, the environment or the communities in which Sayona operates.

Sayona currently has operations in Australia and Canada and expects to continue to conduct operations there and possibly other international locations in the future. Because Sayona conducts operations internationally, Sayona’s operations are governed by and involve interaction with many levels of government across various jurisdictions, including in Australia and Canada, and Sayona is subject to political, social, legal and economic risks such as:

Although Sayona has established formal policies and procedures for preventing violations of and monitoring compliance with the various laws and regulations to which it is subject, the occurrence of any one or combination of the above events, many of which are beyond Sayona’s control, could expose Sayona, its directors and its senior management to civil or criminal liability or other sanctions. This could have a material adverse effect on Sayona’s reputation, business and financial performance. In the case of an alleged violation of the applicable anti-corruption legislation, an investigation may be expensive and require significant time and attention from Sayona’s senior management and may adversely affect Sayona’s reputation.

Sayona’s financial performance, operations, share price and profitability may be adversely affected due to circumstances in the countries where Sayona operates, particularly in Canada. Changes in political, regulatory, or fiscal frameworks in these countries could adversely impact Sayona’s financial performance, operations, share price and profitability.

In particular, Sayona’s properties in Canada may be of particular interest or sensitivity to one or more interest groups, including aboriginal groups (which are generally referred to as “First Nations”). Sayona has mining projects in Québec that are or may be in areas with a First Nations presence. The nature and extent of First Nation rights and title remains the subject of active debate, claims and litigation in Canada. Intergovernmental relations between First Nation authorities and federal, provincial and territorial authorities are evolving. It is Sayona’s practice to work closely with and consult with First Nations in areas in which Sayona’s projects are located or which could be impacted by Sayona’s activities. However, there is no assurance that relationships with such groups will be positive. Accordingly, it is possible that Sayona’s permitting activities, profitable production, exploration or development activities on Sayona’s Canadian properties could be delayed, interrupted or otherwise adversely affected in the future by political uncertainty, native land claims entitlements, expropriations of property, financial arrangements, changes in applicable law, governmental policies and policies of relevant interest groups, including those of First Nations. Any changes in law or relations or shifts in political conditions may be beyond Sayona’s control, or Sayona may enter into agreements with First Nations, all of which may adversely affect Sayona’s business and operations and if significant, may result in the impairment or loss of mineral concessions or other mineral rights, or may make it impossible to continue Sayona’s mineral production, exploration or development activities in the applicable area, any of which could have an adverse effect on Sayona’s financial condition and results of operations.

Sayona operates in jurisdictions that are governed by native title and heritage legislation, including in Australia and Canada. Native title and heritage legislation may affect Sayona’s ability to gain access to prospective exploration areas or obtain required permits and licenses. Sayona may, from time to time, be required

to negotiate with Indigenous landowners and First Nations peoples for access and other rights required in order to mine on particular properties. There may be significant delays and costs associated with these negotiations in order to reach an agreement acceptable to all relevant parties. This may delay or halt Sayona’s operations and development activities in certain areas and affect its financial results accordingly.

Indigenous interests and rights as well as related consultation issues may impact Sayona’s ability to pursue exploration, development and mining at certain of Sayona’s properties in Québec and Western Australia. There is no assurance that claims or other assertion of rights by tribal communities and stakeholders or consultation issues will not arise on or with respect to Sayona’s properties or activities. These could result in significant costs and delays or materially restrict Sayona’s activities. Opposition by indigenous landowners/tribal communities and stakeholders to Sayona’s presence, operations or development on land subject to their traditional territory or title claims or in areas of cultural significance could negatively impact Sayona in terms of permitting delay, public perception, costly legal proceedings, potential blockades or other interference by third parties in Sayona’s operations, or court-ordered relief impacting Sayona’s operations. In addition, Sayona may be required to, or may voluntarily, enter into certain agreements with such tribal communities in order to facilitate development of Sayona’s properties, which could reduce the expected earnings or income from any future production.

Based on the products in Sayona’s supply chain and the services it procures, Sayona’s operations and supply chain are exposed to human rights issues, including modern slavery. Modern slavery can occur in all industries and sectors, but some products and services are associated with higher incidences of modern slavery. For instance, products in Sayona’s supply chain, including materials, chemicals, textiles and technology, are considered to be at a higher risk of being impacted by modern slavery. Additionally, certain services Sayona procures, including those associated with construction, cleaning and laundry services, logistics and transportation services (including trucking, maritime freight and storage), are also at a higher risk of being impacted by modern slavery. Any indication, real or perceived, that Sayona has contributed to or is linked in any way to human rights issues like modern slavery could have an adverse impact on Sayona’s business and reputation.

To the extent commercially available, Sayona maintains insurance to protect against certain risks in such amounts and scope as the Sayona board and Sayona’s management determine is appropriate. However, no assurance can be made that Sayona will be able to obtain or maintain insurance coverage at reasonable rates, or at all.

Additionally, Sayona’s insurance policies may not be sufficient to cover all of the potential risks associated with Sayona’s operations. Any coverage Sayona obtains may not be adequate and may not cover all risks or claims on acceptable terms. Sayona is unable to control whether any insurance coverage or policy ultimately mitigates a claim made. Losses, liabilities and delays arising from uninsured or underinsured events could have a material adverse impact on the operations, financial performance and financial position of Sayona.

The market price of Sayona ordinary shares has been and may continue to be highly volatile and subject to wide fluctuations. The market price for Sayona ADSs may also be highly volatile and subject to wide fluctuations. For instance, from July 1, 2023, through December 31, 2024, the closing price of Sayona ordinary shares on the ASX ranged from as high as AU$0.19 to as low as AU$0.022. In addition, the trading volume of Sayona ordinary shares and Sayona ADSs may fluctuate and cause significant price variations to occur. If the market price of Sayona ordinary shares or Sayona ADSs declines significantly, you may be unable to resell your Sayona ordinary shares or Sayona ADSs at or above the value of the merger consideration when received, if at all. Sayona cannot assure you that the market price of Sayona ordinary shares or Sayona ADSs will not fluctuate or significantly decline in the future.

Some specific factors that could negatively affect the price of Sayona ordinary shares or Sayona ADSs or result in fluctuations in the price and trading volume include:

When the market price of a stock is volatile, certain holders of that stock may institute securities class action litigation against the company that issued the stock. If any Sayona shareholders or Sayona ADS holders brought a lawsuit against Sayona, Sayona could incur substantial costs defending the lawsuit or any future securities class litigation that may be brought against Sayona.

As an Australian public company, Sayona is subject to different organizational requirements than a corporation incorporated under the laws of Delaware. The Constitution, as well as the Australian Corporations Act, set forth various rights and obligations that are distinct to Australian companies, such as Sayona. These requirements may limit Sayona’s ability to take certain actions, including provisions that:

Sayona is also subject to Australian laws governing a change of control or changes in management. For example, the Australian Corporations Act includes provisions that:

In addition, Sayona is also subject to Australia’s takeovers laws. Australia has a peer review body that operates as the primary forum for the resolution of takeover disputes in Australia (the “Takeovers Panel”). ASIC is the main body responsible for regulating and enforcing Australia’s takeovers laws and has the power to refer

matters to the Takeovers Panel. Australia’s takeovers laws regulate both Australian entities listed on a prescribed financial market operated in Australia and Australian companies that have more than 50 registered members. For so long as Sayona meets this criteria, it will be subject to the rules and restrictions applying under Australia’s takeovers laws.

Australian takeovers laws prohibit a person acquiring a relevant interest in the voting shares of Sayona, where, as a result of the acquisition, a person’s voting power in the company increases from 20% or below to more than 20%, or from a starting point that is above 20% and below 90%, subject to certain exceptions.

See the section of this proxy statement/prospectus entitled “Comparison of Rights of Sayona Shareholders and Piedmont Stockholders” beginning on page 220 for further details.

Sayona has never declared any dividends and does not anticipate that it will do so in the foreseeable future. Sayona currently intends to retain future earnings, if any, to finance the development of its business. As a result, a return on your investment will only occur if the Sayona ordinary share or Sayona ADS price, as applicable, appreciates. Sayona cannot assure you that Sayona ordinary shares or Sayona ADSs will appreciate in value or even maintain the value of the merger consideration when received. You may not realize a return on your investment in Sayona ordinary shares or Sayona ADSs, and you may even lose your entire investment in Sayona ordinary shares or Sayona ADSs. Therefore, you should not rely on an investment in Sayona ordinary shares or Sayona ADSs as a source for any future dividend income.

The trading market for Sayona ordinary shares and Sayona ADSs will be influenced by the research and reports that securities or industry analysts publish about Sayona and its business. Securities and industry analysts may discontinue research on Sayona, to the extent such coverage currently exists, or in other cases, may never publish research on Sayona. If no, or too few, securities or industry analysts commence coverage of Sayona, the trading price for Sayona ordinary shares and Sayona ADSs would likely be negatively affected. In the event securities or industry analysts initiate coverage, if one or more of the analysts who cover Sayona downgrade Sayona ordinary shares or Sayona ADSs or publish inaccurate or unfavorable research about Sayona’s business, the market price of Sayona ordinary shares and Sayona ADSs would likely decline. If one or more of these analysts cease coverage of Sayona or fail to publish reports on Sayona regularly, demand for Sayona ordinary shares and Sayona ADSs could decrease, which might cause Sayona’s price and trading volume to decline.

As a company incorporated under the laws of Queensland, Australia, Sayona is subject to Australian insolvency laws and may also be subject to the insolvency laws of other jurisdictions in which Sayona conducts business or has assets. These laws may apply where any insolvency proceedings or procedures are to be initiated against Sayona. Australian insolvency laws may offer Sayona shareholders or Sayona ADS holders less protection than they would have had under U.S. insolvency laws and it may be more difficult (or even impossible) for shareholders to recover the amount they could expect to recover in a liquidation under U.S. insolvency laws.

This proxy statement/prospectus contains forward-looking statements as that term is defined in Section 27A of the U.S. Securities Act, and Section 21E of the U.S. Exchange Act, as amended by the Private Securities Litigation Reform Act of 1995. Forward-looking statements can sometimes be identified by the use of forward-looking terms such as “believes,” “expects,” “may,” “will,” “shall,” “should,” “would,” “could,” “potential,” “seeks,” “aims,” “projects,” “predicts,” “is optimistic,” “intends,” “plans,” “estimates,” “targets,” “anticipates,” “continues” or other comparable terms or negatives of these terms, but not all forward-looking statements include such identifying words. Forward-looking statements are based upon current plans, estimates and expectations that are subject to risks, uncertainties and assumptions. Should one or more of these risks or uncertainties materialize, or should underlying assumptions prove incorrect, actual results may vary materially from those indicated or anticipated by such forward-looking statements. Sayona and Piedmont can give no assurance that such plans, estimates or expectations will be achieved and therefore, actual results may differ materially from any plans, estimates or expectations in such forward-looking statements. Important factors that could cause actual results to differ materially from such plans, estimates or expectations include: