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As filed with the Securities and Exchange Commission on May 5, 2026.

Registration No. 333-            

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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM S-4

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

ATII Holdings Inc.*

(Exact name of Registrant as Specified in its Charter)

For Co-Registrants, see “Table of Co-Registrants” below.

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2093 Philadelphia Pike #1968

Claymont, DE 19703

(725) 312-2430

(Address, including zip code, and telephone number, including area code, of Registrant’s principal executive offices)

Long Long

Chief Executive Officer

2093 Philadelphia Pike #1968

Claymont, DE 19703

(725) 312-2430

(Name, address, including zip code, and telephone number, including area code, of agent for service)

Copies to:

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Approximate date of commencement of proposed sale to the public: As soon as practicable after this registration statement is declared effective and all other conditions to the business combination described in the enclosed proxy statement/prospectus have been satisfied or waived.

If the securities being registered on this Form are being offered in connection with the formation of a holding company and there is compliance with General Instruction G, check the following box. ☐

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐

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If this Form is a post-effective amendment filed pursuant to Rule 462(d) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

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If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act. ☐

If applicable, place an X in the box to designate the appropriate rule provision relied upon in conducting this transaction:

Exchange Act Rule 13e-4(i) (Cross-Border Issuer Tender Offer) ☐

Exchange Act Rule 14d-1(d) (Cross-Border Third-Party Tender Offer) ☐

The registrant and co-registrant hereby amend this registration statement on such date or dates as may be necessary to delay its effective date until the registrant and co-registrant shall file a further amendment which specifically states that this registration statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act, or until the registration statement shall become effective on such date as the Securities and Exchange Commission, acting pursuant to Section 8(a), may determine.

TABLE OF CO-REGISTRANTS

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PRELIMINARY — SUBJECT TO COMPLETION, DATED MAY 5, 2026

PROXY STATEMENT FOR EXTRAORDINARY GENERAL MEETING OF

ARCHIMEDES TECH SPAC PARTNERS II CO.

(a Cayman Islands exempted company)

PROSPECTUS FOR UP TO 251,510,000 SHARES OF COMMON STOCK AND
11,920,000 WARRANTS TO PURCHASE SHARES OF COMMON STOCK

OF

ATII Holdings Inc.

(to be renamed “Forge Nano Holdings Inc.” in connection with the Business Combination described herein)

The board of directors of Archimedes Tech SPAC Partners II Co., a Cayman Islands exempted company (“ATII” or the “Company”), has unanimously approved: (1) the merger of ATII with and into ATII Holdings Inc., a Delaware corporation and a wholly-owned subsidiary of ATII (“Pubco”), with Pubco surviving such merger (the “Domestication Merger”) pursuant to the Merger Agreement attached to this proxy statement/prospectus as Annex A (the “Merger Agreement”), as more fully described elsewhere in this proxy statement/prospectus; (2) at least one day after the effective time of the Domestication Merger (the “Domestication Merger Effective Time”), (i) the merger of ATII Merger Sub Inc., a Delaware corporation and a wholly-owned subsidiary of ATII (“Merger Sub I”) with and into Forge Nano, Inc., a Delaware corporation (“Forge Nano”), with Forge Nano surviving (the “Initial Surviving Corporation”) such merger (the “First Company Merger”), pursuant to the Merger Agreement and as more fully described elsewhere in this proxy statement/prospectus and (ii) immediately following the effective time of the First Company Merger (the “First Effective Time”), the merger of the Initial Surviving Corporation with and into ATII Merger Sub II, LLC, a Delaware limited liability company and a wholly-owned subsidiary of ATII (“Merger Sub II”), with Merger Sub II surviving (the “Surviving Company”) such merger (the “Second Company Merger” and together with the First Company Merger, the “Company Mergers”), pursuant to the Merger Agreement and as more fully described elsewhere in this proxy statement/prospectus; and (3) the other transactions contemplated by the Merger Agreement and documents related thereto (such transactions, together with the Domestication Merger, the Company Mergers, collectively, the “Proposed Transaction” or “Business Combination”).

On April 20, 2026, ATII, Pubco, Merger Sub I, Merger Sub II and Forge Nano entered into the Merger Agreement. Capitalized terms used in this proxy statement/prospectus but not otherwise defined herein have the meanings given to them in the Merger Agreement.

The Domestication Merger

Pursuant to the Merger Agreement, and subject to the terms and conditions set forth therein, ATII will re-domicile and become a Delaware corporation by merging with Pubco, following which the separate corporate existence of ATII will cease and Pubco will continue as the surviving corporation. At the Domestication Merger Effective Time, Pubco will adopt Delaware organizational documents, which will provide, among other things, that the name of Pubco will be changed to “Forge Nano Holdings Inc.”

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Immediately prior to the Domestication Merger Effective Time, each then issued and outstanding unit of ATII (an “ATII Unit”) will separate and convert automatically into one ordinary share, par value $0.0001 per share, of ATII (an “ATII Ordinary Share”) and one-half of one warrant of ATII, each whole warrant entitling the holder thereof to acquire one ATII Ordinary Share at a purchase price of $11.50 per share (the “ATII Warrants”), and all ATII Units will cease to be outstanding and will cease to exist. At the Domestication Merger Effective Time, each then issued and outstanding ATII Ordinary Share (which, for the avoidance of doubt, includes ATII Ordinary Shares held as a result of the separation of the ATII Units) will be cancelled in exchange for the right to receive one share of common stock, par value $0.0001 per share, of Pubco (each, a share of “Pubco Common Stock”) and each ATII Warrant that is outstanding and unexercised shall convert automatically into a warrant to acquire one share of Pubco Common Stock at a purchase price of $11.50 per share (each, a “Pubco SPAC Warrant”), pursuant to the terms of the Warrant Agreement, dated as of February 10, 2025, by and between the Purchaser and Odyssey Transfer and Trust Company, as warrant agent (the “ATII Warrant Agreement”).

For more information, please see the section of this proxy statement entitled “Proposal No. 2 – The Domestication Merger Proposal.”

First Company Merger

Pursuant to the Merger Agreement, and subject to the terms and conditions set forth therein, at least one day following the Domestication Merger Effective Time, Merger Sub I will merge with and into Forge Nano, with Forge Nano surviving as the Initial Surviving Corporation and as a result of which the holders of the issued and outstanding capital stock of Forge Nano will receive shares of Pubco Common Stock in exchange for the issued and outstanding capital stock of Forge Nano. As a result of the First Company Merger, Forge Nano will become a wholly-owned subsidiary of Pubco.

At the First Effective Time: (i) each share of each class of Forge Nano’s preferred stock, par value $0.0001 per share (the “Forge Nano Preferred Stock”), that is issued and outstanding immediately prior to the First Effective Time shall be converted into shares of Forge Nano Common Stock (as defined below) pursuant to Forge Nano’s organizational documents as in effect immediately prior to the First Effective Time; (ii) each share of Forge Nano’s common stock, par value $0.0001 per share (the “Forge Nano Common Stock”), that is issued and outstanding immediately prior to the First Effective Time (including shares of Forge Nano Common Stock issued upon conversion of the shares of Forge Nano Preferred Stock, but not including treasury shares which will be canceled immediately prior to the First Effective Time) will be cancelled and automatically converted into the right to receive, without interest, the applicable pro rata portion of the Closing Payment Shares (as defined below) for such number of shares of Forge Nano Common Stock (the “Applicable Per Share Merger Consideration”); (iii) each outstanding warrant of Forge Nano (a “Forge Nano Warrant”) that is issued and outstanding and unexpired immediately prior to the First Effective Time will be assumed by Pubco and become a corresponding Pubco warrant (a “Pubco Forge Nano Warrant”), subject to the same terms and conditions (including vesting and exercisability) as were applicable to the corresponding Forge Nano Warrant immediately prior to the First Effective Time; and (iv) each option or other right to acquire securities of Forge Nano and/or its affiliates held by Ascent Funds International Management LLC, including those specified in the Amended and Restated Consulting Agreement between Ascent Funds International Management LLC and the Company dated September 1, 2025 (the “Forge Nano Ascent Options” and together with the Forge Nano Warrants, the “Forge Nano Convertible Securities”), that is issued and outstanding and unexpired immediately prior to the First Effective Time will be cancelled and converted into one warrant to purchase shares of Pubco Common Stock (a “Pubco Ascent Warrant” and together with the Pubco Forge Nano Warrants, the “Pubco Convertible Securities”) pursuant to the Pubco Ascent Warrant Agreement, substantially in the form attached to the Merger Agreement. Under the Merger Agreement, “Closing Payment Shares” means such number of shares of Pubco Common Stock equal to (a)(i) $1,200,000,000 divided by (ii) $10.00 minus (b) the Pubco Common Stock issuable upon exercise of any Pubco Convertible Securities issued in exchange for Forge Nano Convertible Securities, if any.

At the First Effective Time, each option to purchase shares of Forge Nano Common Stock (each, a “Forge Nano Option”) that is issued and outstanding and unexpired immediately prior to the First Effective Time will be converted into an option to purchase shares of Pubco Common Stock (each, a “Pubco Option”) on substantially the same terms and conditions, including with respect to vesting and termination-related provisions (as applicable, except that such Pubco Options will relate to the number of whole shares of Pubco Common Stock (rounded down to the nearest whole share) equal to the product (rounded down to the nearest whole number) of (a) the number of shares of Forge Nano Common Stock subject to such Forge Nano Option immediately prior to the First Effective Time and (b) the quotient of (1) the Applicable Per Share Merger Consideration divided by (ii) the Equity Award Conversion Amount (as defined in the Merger Agreement), with an exercise price per Pubco Option (rounded up to the nearest whole cent) equal to the quotient obtained by dividing (x) the exercise price per Forge Nano Option by (ii) the Equity Award Conversion Amount.

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Earn-Out

Pursuant to the terms of the Merger Agreement, and subject to the terms and conditions set forth therein, the Forge Nano Stockholders who receive Closing Payment Shares and the holders of Pubco Convertible Securities issued in exchange for Forge Nano Convertible Securities will be entitled to receive a proportional amount of up to an aggregate of 90,000,000 additional shares of Pubco Common Stock (the “Earn-Out Shares”), issuable upon achievement of certain milestones during the five (5) year period following the Closing Date (the “Earn-Out Period”). The Earn-Out Shares will be issued at or prior to the Closing to the Escrow Agent and will be disbursed therefrom upon achievement of the applicable milestones as follows:

The milestones applicable to the Earn-Out Shares operate on a cumulative basis, such that if a higher milestone is achieved, the lower milestones are deemed achieved as well and the Earn-Out Shares attributable to such achieved milestone and each lower milestone will be disbursed. The Earn-Out Shares attributable to holders of Pubco Convertible Securities issued in exchange for Forge Nano Convertible Securities pursuant to the Merger Agreement will only be disbursed by the Escrow Agent if an applicable milestone is achieved upon the exercise, conversion or settlement of any Pubco Convertible Securities in accordance with their terms.

Second Company Merger

Pursuant to the Merger Agreement, and subject to the terms and conditions set forth therein, immediately following the First Effective Time, the Initial Surviving Corporation will merge with and into Merger Sub II, with Merger Sub II surviving as the Surviving Company and Pubco acquiring one membership interest in Surviving Company and such membership interest will constitute the only outstanding equity of the Surviving Company.

For more information, please see the section of this proxy statement entitled “Proposal No. 1 – The Business Combination Proposal – Merger Consideration.”

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The ATII Units, ATII Ordinary Shares and ATII Warrants, in each case, that were issued in the initial public offering (“IPO”) pursuant to the final prospectus of ATII, dated as of February 10, 2025, and filed with the SEC on February 11, 2025, are currently listed on Nasdaq under the symbols “ATIIU,” “ATII” and “ATIIW,” respectively. Pubco intends to apply to obtain the listing of (i) the Pubco Common Stock and (ii) the Pubco SPAC Warrants that were originally issued as part of the ATII Units in the IPO on Nasdaq under the proposed symbols NANO and NANOW, respectively, upon the Closing. Pubco will not have publicly traded units following the Closing. Pursuant to the terms of the Merger Agreement, as a closing condition, ATII is required to cause the Pubco Common Stock to be issued in connection with the Business Combination to be approved for listing on Nasdaq, but there can be no assurance that such listing condition will be met. If such listing condition is not met, the Business Combination will not be consummated unless the listing condition is waived by all of the parties to the Merger Agreement. It is important for you to know that, at the time of the extraordinary general meeting, ATII may not have received from Nasdaq confirmation of the listing of the Pubco Common Stock. As a result, you may be asked to vote to approve and adopt the Business Combination Proposal and the other proposals included in the accompanying proxy statement/prospectus without such confirmation, and, further, it is possible that such confirmation may never be received, and the Business Combination could still be consummated if such condition is waived by all of the parties to the Merger Agreement and therefore the Pubco Common Stock would not be listed on any nationally recognized securities exchange.

Upon consummation of the Business Combination, the post-Closing share ownership of Pubco under (1) the No Additional Redemptions Scenario, (2) the 25% Redemptions Scenario, (3) the 50% Redemptions Scenario, (4) the 75% Redemptions Scenario and (5) the Maximum Redemptions Scenario, excluding the dilutive effect of Pubco SPAC Warrants, Pubco Forge Nano Warrants, Pubco Ascent Warrants, Pubco Options, PIPE Warrants, Reset PIPE Warrants and Earn-Out Shares, would be as follows:

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The following table illustrates varying ownership levels of Pubco immediately following the Business Combination on a fully diluted basis⁽¹⁾:

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In addition to the changes in percentage ownership depicted above, variation in the levels of redemptions will impact the dilutive effect of certain equity issuances related to the Business Combination, which would not otherwise be present in an underwritten public offering. Increasing levels of redemptions by holders of ATII Public Shares will increase the dilutive effect of these issuances on non-redeeming holders of the ATII Public Shares.

For more information, please see the sections entitled “Unaudited Pro Forma Condensed Combined Financial Information” and “Proposal No. 1 — The Business Combination Proposal — Ownership of Pubco After the Closing.”

All of the relative percentages above are for illustrative purposes only and are based upon certain assumptions as described in the section entitled “Unaudited Pro Forma Condensed Combined Financial Information”. For more information, including the ownership percentages in the No Additional Redemptions Scenario and the effect of certain dilutive securities, see the section entitled “Proposal No. 1 – The Business Combination Proposal — Ownership of Pubco After the Closing”.

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Compensation to be Received by the Sponsor

As disclosed in the IPO prospectus, ATII may issue working capital loans (the “Working Capital Loans”) that would either be repaid upon consummation of an initial business combination, without interest, or, at the lender’s discretion, up to $1,500,000 of such Working Capital Loans may be convertible into units of ATII, at a price of $10.00 per unit. If ATII completes an initial business combination by November 12, 2026 (or such later date that may be approved by holders of ATII Ordinary Shares in accordance with the Current Charter) (the “Completion Window”), ATII would repay the Working Capital Loans out of the proceeds of the Trust Account released to ATII in connection with its initial business combination. Otherwise, the Working Capital Loans would be repaid only out of funds held outside of the Trust Account. In the event that an initial business combination is not completed during the Completion Window, ATII may use a portion of proceeds held outside of the Trust Account to repay the Working Capital Loans, but no proceeds held in the Trust Account would be used to repay the Working Capital Loans. The units of ATII into which such Working Capital Loans may be convertible would be identical to the ATII Private Units issued concurrently with the IPO. As of the date of this proxy statement/prospectus, ATII has no outstanding borrowings under Working Capital Loans.

In addition, ATII’s sponsor, directors or officers, or any of their respective affiliates, will be reimbursed for any out-of-pocket expenses relating to identifying, investigating and completing an initial business combination.

Conflicts of interest

Since the Sponsor, its affiliates and representatives and certain initial shareholders of ATII (the “Initial Shareholders”), have interests that are different, or in addition to (and which may conflict with), the interests of the holders of ATII Ordinary Shares generally, a conflict of interest may exist in determining whether the Business Combination with Forge Nano is appropriate. Such interests include that the Initial Shareholders will lose their entire investment in ATII in the event ATII does not complete an initial business combination during the Completion Window. When you consider the recommendation of the ATII Board in favor of approval of the Business Combination Proposal and each of the other proposals presented to the holders of ATII Ordinary Shares in the accompanying proxy statement/prospectus, you should keep in mind that the Sponsor and Initial Shareholders have interests in such proposals that are different from, or in addition to (and which may conflict with), those of the holders of ATII Ordinary Shares generally.

These conflicts of interest include, among other things, the interests listed below:

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These interests may influence the directors of ATII in making their recommendation that you vote in favor of the Business Combination Proposal and each of the other proposals presented to the holders of ATII Ordinary Shares in the accompanying proxy statement/prospectus. These interests were considered by the ATII Board when it approved the Business Combination and resolved to recommend that the holders of ATII Ordinary Shares vote in favor of such proposals.

For more information, please see Section — “DIRECTORS, OFFICERS, EXECUTIVE COMPENSATION AND CORPORATE GOVERNANCE OF ATII PRIOR TO THE BUSINESS COMBINATION — Conflicts of interest” on page 196.

ATII will hold an extraordinary general meeting of the holders of ATII Ordinary Shares (the “extraordinary general meeting”) to consider matters relating to the Business Combination at          Eastern Time, on         , 2026. The extraordinary general meeting will be a virtual meeting conducted via live webcast. For the purposes of Cayman Islands law and the Current Charter, the physical location of the meeting will be at. You or your proxyholder will be able to attend and vote at the extraordinary general meeting online by visiting          and using a control number assigned by Odyssey Transfer and Trust Company (the “Transfer Agent”). To register and receive access to the extraordinary general meeting, registered holders of ATII Ordinary Shares and “beneficial owners” of ATII Ordinary Shares (those holding shares through a stock brokerage account or by a bank or other holder of record) will need to follow the instructions applicable to them provided in the accompanying proxy statement/prospectus.

If you have any questions or need assistance voting your ATII Ordinary Shares, please contact           , our proxy solicitor, by email at         . Individuals may also call          toll free at         ; banks and brokers can call         . The notice of the extraordinary general meeting and the proxy statement/prospectus relating to the Business Combination will be available at         .

This document is (i) a prospectus related to the issuance by Pubco of Pubco Common Stock and Pubco Warrants in the Business Combination and pursuant to the terms of the Merger Agreement, and (ii) a proxy statement for ATII to use in soliciting proxies for the extraordinary general meeting.

This proxy statement/prospectus provides shareholders of ATII with detailed information about the Business Combination and other matters to be considered at the extraordinary general meeting of ATII. We encourage you to read this entire document, including the Annexes and other documents referred to herein, carefully and in their entirety. You should also carefully consider the risk factors described under the heading “Risk Factors” beginning on page 65.

NEITHER THE SEC NOR ANY STATE SECURITIES REGULATORY AGENCY HAS APPROVED OR DISAPPROVED THE TRANSACTIONS DESCRIBED IN THIS PROXY STATEMENT/PROSPECTUS, PASSED UPON THE MERITS OR FAIRNESS OF THE BUSINESS COMBINATION OR PASSED UPON THE ADEQUACY OR ACCURACY OF THE DISCLOSURE IN THIS PROXY STATEMENT/PROSPECTUS. ANY REPRESENTATION TO THE CONTRARY CONSTITUTES A CRIMINAL OFFENSE.

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ARCHIMEDES TECH SPAC PARTNERS II CO.

Cayman Islands Exempted Company

(Company Number 410717)

2093 Philadelphia Pike #1968

Claymont, DE 19703

(725) 312-2430

NOTICE OF EXTRAORDINARY GENERAL MEETING TO BE HELD ON         , 2026

To the Holders of Ordinary Shares of Archimedes Tech SPAC Partners II Co.:

NOTICE IS HEREBY GIVEN that an extraordinary general meeting (including any adjournments or postponements thereof, the “extraordinary general meeting”) of holders of ordinary shares, par value $0.0001 (each, an “ATII Ordinary Share”), of Archimedes Tech SPAC Partners II Co., a Cayman Islands exempted company (“ATII”, the “Company”, “we”, “us” and “our”), will be held virtually via live webcast at          Eastern Time on         , 2026 (unless the extraordinary general meeting is adjourned or postponed). Holders of ATII Ordinary Shares will be able to virtually attend and vote at the extraordinary general meeting by visiting         (the “extraordinary general meeting website”). To attend the extraordinary general meeting, you must pre-register at          by         Eastern Time on         , 2026. For purposes of attendance at the extraordinary general meeting, all references in the enclosed proxy statement to “present” shall mean virtually present at the extraordinary general meeting. For the purposes of the Companies Act (as revised) of the Cayman Islands (the “Companies Act”) and the Amended and Restated Memorandum and Articles of Association of ATII (as may be amended from time to time, the “Current Charter”), the physical location of the extraordinary general meeting will be at the offices of ATII at. The extraordinary general meeting is being held for the following purposes:

“RESOLVED, as an Ordinary Resolution of the holders of ATII Ordinary Shares, that ATII’s entry into the Agreement and Plan of Merger, dated as of April 20, 2026, by and among ATII, ATII Holdings Inc., a Delaware corporation and a wholly-owned subsidiary of ATII (“Pubco”), ATII Merger Sub Inc., a Delaware corporation and a wholly-owned subsidiary of ATII (“Merger Sub I”), ATII Merger Sub II, LLC, a Delaware limited liability company and a wholly owned subsidiary of ATII (“Merger Sub II”), and Forge Nano, Inc., a Delaware corporation (“Forge Nano”) (as may be amended and/or restated from time to time, the “Merger Agreement”) (a copy of which is attached to the proxy statement/prospectus as Annex A), pursuant to which, in accordance with the terms and subject to the conditions of the Merger Agreement, among other things, (i) ATII will merge with and into Pubco (the “Domestication Merger”), with Pubco continuing as the surviving corporation in the Domestication Merger pursuant to the Companies Act (as revised) of the Cayman Islands (the “Companies Act”) and the Delaware General Corporation Law (as amended, the “DGCL”), (ii) at least one day following the effective time of the Domestication Merger, Merger Sub I will merge with and into Forge Nano (the “First Company Merger”), with Forge Nano continuing as the surviving corporation in the First Company Merger and a wholly-owned subsidiary of Pubco (the

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“Initial Surviving Corporation”) in accordance with the DGCL, and (iii) immediately following the effective time of the First Company Merger (the “First Effective Time”), the Initial Surviving Corporation will merge with and into Merger Sub II (the “Second Company Merger”, and together with the First Company Merger, the “Company Mergers”), with Merger Sub II continuing as the surviving company in the Second Company Merger and a wholly-owned subsidiary of Pubco (the “Surviving Company”) in accordance with the DGCL and the Delaware Limited Liability Company Act, as amended, be hereby authorized, approved, ratified and confirmed in all respects.”

(2)Proposal No. 2 — The Domestication Merger Proposal — To consider and vote upon a proposal to approve, by way of Special Resolution of the holders of ATII Ordinary Shares, subject to the approval of the Business Combination Proposal, among other things, (i) at least one (1) day prior to the First Effective Time, the consummation of the Domestication Merger by executing and filing a Plan of Merger, appended to the accompanying proxy statement/prospectus as Exhibit 3.4 (the “Plan of Merger”) (and any other documents required by the Companies Act) with the Registrar of Companies in the Cayman Islands (the “Cayman Registrar”) pursuant to Sections 233 and 237 of the Companies Act, filing a certificate of merger with the Secretary of State of the State of Delaware and making such other filings or recordings, in each case, in accordance with the Companies Act and the relevant provisions of the DGCL, in connection with the Domestication Merger (the time when the Plan of Merger is registered by the Cayman Registrar and when the certificate of merger is filed with the Secretary of State of the State of Delaware, or such later time as may be specified in the Plan of Merger and certificate of merger, being the “Domestication Merger Effective Time”), (ii) that, upon the Domestication Merger Effective Time, the certificate of incorporation and bylaws of Pubco, each as in effect immediately prior to the Domestication Merger Effective Time, be amended and restated in the form appended to the accompanying proxy statement/prospectus as Annex B-1 (the “Proposed Charter”) and Annex B-2 (the “Proposed Bylaws”), respectively, and as so amended, be the certificate of incorporation and bylaws of Pubco, until thereafter supplemented or amended in accordance with the terms therein and the applicable provisions of the DGCL (with such changes as may be agreed in writing by ATII and Forge Nano), including providing that the name of Pubco will be amended to be “Forge Nano Holdings, Inc.” and (iii) that any one director of ATII (each, an “ATII Director”) on behalf of ATII and, with the authorization of any ATII Director, any of ATII’s officers on behalf of ATII, be authorized to execute and submit, or cause the submission of, the Plan of Merger, together with any supporting documentation, for registration to the Cayman Registrar and filing a certificate of merger with the Secretary of State of the State of Delaware and making such other filings or recordings, in each case, in accordance with the Companies Act and the relevant provisions of the DGCL, in connection with the Domestication Merger. We refer to this proposal as the “Domestication Merger Proposal.” The full text of the resolution to be considered and if thought fit, passed and approved is as follows:

“RESOLVED, as a Special Resolution of the holders of ATII Ordinary Shares, subject to the approval of the Business Combination Proposal, among other things: (i) at least one (1) day prior to the First Effective Time, that ATII shall consummate the Domestication Merger by executing and filing a Plan of Merger, appended to the accompanying proxy statement/prospectus as Exhibit 3.4 (the “Plan of Merger”) (and any other documents required by the Companies Act) with the Registrar of Companies in the Cayman Islands (the “Cayman Registrar”) pursuant to Sections 233 and 237 of the Companies Act, filing a certificate of merger with the Secretary of State of the State of Delaware and making such other filings or recordings, in each case, in accordance with the Companies Act and the relevant provisions of the DGCL, in connection with the Domestication Merger (the time when the Plan of Merger is registered by the Cayman Registrar and when the certificate of merger is filed with the Secretary of State of the State of Delaware, or such later time as may be specified in the Plan of Merger and certificate of merger, being the “Domestication Merger Effective Time”), (ii) upon the Domestication Merger Effective Time, the certificate of incorporation and bylaws of Pubco, each as in effect immediately prior to the Domestication Merger Effective Time, be amended and restated in the form appended to the accompanying proxy statement/prospectus as Annex B-1 (the “Proposed Charter”) and Annex B-2 (the “Proposed Bylaws”), respectively, and as so amended, be the certificate of incorporation and bylaws of Pubco, until thereafter supplemented or amended in accordance with the terms therein and the applicable provisions of the DGCL (with such changes as may be agreed in writing by ATII and Forge Nano), including providing that the name of Pubco will be amended to be “Forge Nano Holdings, Inc.” and (iii) that any one director of ATII (each, an “ATII Director”) on behalf of ATII and, with the authorization of any ATII Director, any of ATII’s officers on behalf of ATII, be authorized to execute and submit, or cause the submission of, the Plan of Merger, together with any supporting documentation, for registration to the Cayman Registrar and filing a certificate of merger with the Secretary of State of the State of Delaware and making such other filings or recordings, in each case, in accordance with the Companies Act and the relevant provisions of the DGCL, in connection with the Domestication Merger, in each case, be hereby authorized, approved, ratified and confirmed in all respects.”

(3)Proposal No. 3 – The Director Election Proposal – To consider and vote upon a proposal to approve and adopt, by way of Ordinary Resolution of the holders of ATII Ordinary Shares, the election of six (6) directors that at the Closing will

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comprise the Pubco Board and that such nominated directors be elected to a staggered board (the “Director Election Proposal”). The full text of the resolution to be considered and if thought fit, passed and approved is as follows:

“RESOLVED, as an Ordinary Resolution of the holders of ATII Ordinary Shares, that the six (6) persons listed below be elected to a staggered board, who, upon consummation of the Business Combination, will comprise the board of directors of Pubco in accordance with the terms of the Merger Agreement, the Companies Act, the DGCL and the DLLCA, be, in each case, hereby authorized, approved, ratified and confirmed in all respects:

1.Paul Lichty

2.Michael Danner

3.David Goggins

4.Millicent Pitts-DiCicco

5.Jimmy Smith

6.Ben Landen.”

(4)Proposal No. 4 — The Stock Issuance Proposal — To consider and vote upon a proposal to approve and adopt, by way of Ordinary Resolution of the holders of ATII Ordinary Shares, for purposes of complying with the applicable provisions of Nasdaq Listing Rules 5635(a), (b) and (d), the issuance of more than 20% of the issued and outstanding shares of Pubco Common Stock and securities convertible into shares of Pubco Common Stock upon the completion of the Business Combination (collectively, “Pubco Securities”) to (i) the holders of ATII Ordinary Shares pursuant to the Domestication Merger, (ii) the Forge Nano Stockholders who receive Closing Payment Shares and the holders of Pubco Convertible Securities issued in exchange for Forge Nano Convertible Securities pursuant to the Company Mergers and (iii) to the PIPE Investor and to any other persons pursuant to subscription, purchase, or similar agreements that ATII may enter into prior to Closing (including the PIPE Subscription Agreement, a copy of which is attached to the accompanying proxy statement/ prospectus at Annex H). We refer to this proposal as the “Stock Issuance Proposal.” The full text of the resolution to be considered and if thought fit, passed and approved is as follows:

“RESOLVED, as an Ordinary Resolution of the holders of ATII Ordinary Shares, that, for purposes of complying with the applicable provisions of Nasdaq Listing Rules 5635(a), (b) and (d), the issuance of up to 281,510,000 shares of Pubco Common Stock and securities convertible into shares of Pubco Common Stock, assuming the No Additional Redemptions Scenario, or the issuance of up to 258,510,000 shares of Pubco Common Stock and securities convertible into shares of Pubco Common Stock, assuming the Maximum Redemptions Scenario, upon completion of the Business Combination (collectively, “Pubco Securities”) as set forth below and pursuant to the Merger Agreement, the Pubco Forge Nano Warrant Agreements, the Pubco Ascent Warrant Agreement, the PIPE Subscription Agreement, the PIPE Warrant Certificate and the 2026 Equity Plan, as applicable, be hereby authorized, approved, ratified and confirmed in all respects:

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“RESOLVED, as a Special Resolution of the holders of ATII Ordinary Shares, that the amended and restated memorandum and articles of association of ATII in effect as of immediately prior to the Domestication Merger Effective Time be amended and restated by the deletion in their entirety and the substitution in their place of the Proposed Charter and Proposed Bylaws, respectively (copies of which are attached to the accompanying proxy statement/prospectus as Annex B-1 and Annex B-2, respectively) with effect from the Domestication Merger Effective Time, and that the Proposed Charter and Proposed Bylaws, together with such principal changes as described in the Advisory Organizational Documents Proposals 6A through 6F below, be hereby authorized, approved, ratified and confirmed in all respects.”

(6)Proposal No. 6 — The Advisory Organizational Documents Proposals — To consider and vote upon the following six (6) separate proposals (collectively, the “Advisory Organizational Documents Proposals”) to approve and adopt, on an advisory non-binding basis, by way of Ordinary Resolution of the holders of ATII Ordinary Shares, the following material differences between the Current Charter and the Proposed Organizational Documents:

(A)Advisory Organizational Documents Proposal 6A (Authorized Shares) — to approve and adopt an amendment to the Current Charter, with effect from the Domestication Merger Effective Time, to authorize the amendment and redesignation of the authorized share capital of ATII from (a) 400,000,000 ATII Ordinary Shares and 1,000,000 preference shares, par value $0.0001 per share, of ATII to (b) [500,000,000] shares of Pubco Common Stock and [5,000,000] shares of preferred stock of Pubco, par value $0.0001 per share (“Advisory Organizational Documents Proposal 6A”). The full text of the resolution to be considered and if thought fit, passed and approved is as follows:

“RESOLVED, as an Ordinary Resolution of the holders of ATII Ordinary Shares, on an advisory non-binding basis, that, with effect from the Domestication Merger Effective Time, the authorized share capital of ATII be amended and redesignated from (a) 400,000,000 ATII Ordinary Shares and 1,000,000 preference shares, par value $0.0001 per share, of ATII to (b) [500,000,000] shares of Pubco Common Stock and [5,000,000] shares of preferred stock of Pubco, par value $0.0001 per share, in accordance with the DGCL and the Companies Act (“Advisory Organizational Documents Proposal 6A”), and that Advisory Organizational Documents Proposal 6A be hereby authorized, approved, ratified and confirmed in all respects.”

(B)Advisory Organizational Documents Proposal 6B (Exclusive Forum Provision) — to approve and adopt an amendment to the Current Charter, with effect from the Domestication Merger Effective Time, to authorize adopting Delaware as the exclusive forum for certain stockholder litigation and adopting the federal district courts of the United States as the exclusive forum for resolving complaints asserting a cause of action under the Securities Act of 1933, as amended (the “Securities Act”), with effect from the Domestication Merger Effective Time (“Advisory Organizational Documents Proposal 6B”). The full text of the resolution to be considered and if thought fit, passed and approved is as follows:

“RESOLVED, as an Ordinary Resolution of holders of ATII Ordinary Shares, on an advisory non-binding basis, that, with effect from the Domestication Merger Effective Time, (a) Delaware be adopted as the exclusive forum for certain stockholder litigation and (b) the federal district courts of the United States be adopted as the exclusive forum for asserting a cause of action under the Securities Act of 1933, as amended in accordance with the DGCL and the Companies Act (“Advisory Organizational Documents Proposal 6B”), and that Advisory Organizational Documents Proposal 6B be hereby authorized, approved, ratified and confirmed in all respects.”

(C)Advisory Organizational Documents Proposal 6C (Required Vote to Amend Charter) — to approve and adopt an amendment to the Current Charter, with effect from the Domestication Merger Effective Time, to authorize provisions

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providing that the affirmative vote of at least two-thirds of the voting power of all the then outstanding shares of capital stock of Pubco entitled to vote thereon, voting together as a single class, will be required to amend, alter, repeal or rescind any provision of Articles         of the Proposed Charter in accordance with the DGCL and the Companies Act (provided, that, so long as any shares of Pubco Common Stock remain outstanding, Pubco may not, without the prior affirmative vote of the holders of a majority of the outstanding shares of Pubco Common Stock, voting as a separate class, in addition to any other vote of the holders of shares of capital stock of Pubco required by applicable law or the Proposed Charter, directly or indirectly, whether by amendment or through merger, recapitalization, consolidation or otherwise, amend, alter, change, repeal or adopt any provision of the Proposed Charter in a manner that is inconsistent with, or that otherwise alters or changes the powers, preferences, or special rights of the shares of Pubco Common Stock so as to affect them adversely) (“Advisory Organizational Documents Proposal 6C”). The full text of the resolution to be considered and if thought fit, passed and approved is as follows:

“RESOLVED, as an Ordinary Resolution of the holders of ATII Ordinary Shares, on an advisory non-binding basis, that, with effect from the Domestication Merger Effective Time, provisions providing that the affirmative vote of at least two-thirds of the voting power of all the then outstanding shares of capital stock of Pubco entitled to vote thereon, voting together as a single class, will be required to amend, alter, repeal or rescind any provision of of the Proposed Charter in accordance with the DGCL and the Companies Act (provided, that, so long as any shares of Pubco Common Stock remain outstanding, Pubco may not, without the prior affirmative vote of the holders of a majority of the outstanding shares of Pubco Common Stock, voting as a separate class, in addition to any other vote of holders of shares of capital stock of Pubco required by applicable law or the Proposed Charter, directly or indirectly, whether by amendment or through merger, recapitalization, consolidation or otherwise, amend, alter, change, repeal or adopt any provision of the Proposed Charter in a manner that is inconsistent with, or that otherwise alters or changes the powers, preferences, or special rights of the shares of Pubco Common Stock so as to affect them adversely) (“Advisory Organizational Documents Proposal 6C”), and be hereby authorized, approved, ratified and confirmed in all respects.”

(D)Advisory Organizational Documents Proposal 6D (Removal of Directors) — to approve and adopt an amendment to the Current Charter, with effect from the Domestication Merger Effective Time, to authorize provisions permitting the removal of a director, with or without cause, by the affirmative vote of at least two-thirds of the outstanding shares of capital stock of Pubco entitled to vote generally in the election of directors, voting together as a single class (“Advisory Organizational Documents Proposal 6D”). The full text of the resolution to be considered and if thought fit, passed and approved is as follows:

“RESOLVED, as an Ordinary Resolution, on an advisory non-binding basis, that, with effect from the Domestication Merger Effective Time, provisions permitting the removal of a director, with or without cause, by the affirmative vote of at least two-thirds of the outstanding shares of capital stock of Pubco entitled to vote generally in the election of directors, voting together as a single class (“Advisory Organizational Documents Proposal 6D”), be hereby authorized, approved, ratified and confirmed in all respects.”

(E)Advisory Organizational Documents Proposal 6E (Stockholder Action by Written Consent) — to approve and adopt an amendment to the Current Charter, with effect from the Domestication Merger Effective Time, to authorize provisions that require or permit stockholders to take action at an annual or special meeting and prohibit stockholder action by written consent in lieu of a meeting (“Advisory Organizational Documents Proposal 6E”). The full text of the resolution to be considered and if thought fit, passed and approved is as follows:

“RESOLVED, as an Ordinary Resolution of the holders of ATII Ordinary Shares, on an advisory non-binding basis, that, with effect from the Domestication Merger Effective Time, provisions requiring or permitting holders of shares of capital stock of Pubco to take action at an annual or special meeting and prohibit action by written consent in lieu of a meeting by the holders of shares of capital stock of Pubco (“Advisory Organizational Documents Proposal 6E”), be hereby authorized, approved, ratified and confirmed in all respects.”

(F)Advisory Organizational Documents Proposal 6F (Additional Changes) — to approve and adopt an amendment to the Current Charter, with effect from the Domestication Merger Effective Time, to authorize certain additional changes, including, among other things, (i) making Pubco’s corporate existence perpetual and (ii) removing certain provisions related to ATII’s status as a blank check company that will no longer be applicable upon Closing, all of which the ATII Board believes is necessary to adequately address the needs of Pubco after the Business Combination (“Advisory Organizational

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Documents Proposal 6F”). The full text of the resolution to be considered and if thought fit, passed and approved is as follows:

“RESOLVED, as an Ordinary Resolution of the holders of ATII Ordinary Shares, on an advisory non-binding basis, that, with effect from the Domestication Merger Effective Time, certain additional changes, including, among other things, (i) making Pubco’s corporate existence perpetual and (ii) removing certain provisions related to ATII’s status as a blank check company that will no longer be applicable upon consummation of the Business Combination, in each case, which the ATII Board believes is necessary to adequately address the needs of Pubco after the consummation of the Business Combination (“Advisory Organizational Documents Proposal 6F”), be hereby authorized, approved, ratified and confirmed in all respects.”

(7)Proposal No. 7 – The Equity Incentive Plan Proposal – To consider, approve and adopt, by Ordinary Resolution of the holders of ATII Ordinary Shares, the Forge Nano Holdings Inc. 2026 Omnibus Incentive Compensation Plan (the “2026 Equity Plan”) in connection with the Business Combination (the “Equity Incentive Plan Proposal”). The full text of the resolution to be considered and if thought fit, passed and approved is as follows:

“RESOLVED, as an Ordinary Resolution of the holders of ATII Ordinary Shares, that, in connection with the Business Combination and in accordance with the DGCL and the Companies Act, the Forge Nano Holdings Inc. 2026 Omnibus Incentive Compensation Plan (the “2026 Equity Plan”) be hereby authorized, approved, ratified, confirmed and adopted in all respects.”

(8)Proposal No. 8 — The Adjournment Proposal — To consider and vote upon a proposal to approve and adopt, by way of Ordinary Resolution of the holders of ATII Ordinary Shares, the adjournment of the extraordinary general meeting to a later date or dates, if necessary, to permit further solicitation and vote of proxies in the event that there are insufficient votes for the approval of one or more proposals at the extraordinary general meeting (the “Adjournment Proposal”). The full text of the resolution to be considered and if thought fit, passed and approved is as follows:

“RESOLVED, as an Ordinary Resolution of the holders of ATII Ordinary Shares, that the adjournment of the extraordinary general meeting to a later date or dates, if necessary, to permit further solicitation and vote of proxies in the event that there are insufficient votes for the approval of one or more proposals at the extraordinary general meeting, be hereby authorized, approved, ratified and confirmed in all respects.”

Each of Proposal Nos. 1, 2, 3, 4, 5, and 7 is cross-conditioned on the approval of each other (collectively, the “Condition Precedent Proposals”). The Advisory Organizational Documents Proposal 6A-F and the Adjournment Proposal are not cross-conditioned upon the approval of any other proposal set forth in the accompanying proxy statement/prospectus. Notwithstanding the order of the resolutions on the notice to the extraordinary general meeting, the Adjournment Proposal may be presented first to the holders of ATII Ordinary Shares if, based on the tabulated vote collected at the time of the extraordinary general meeting, there are insufficient votes for, or otherwise in connection with, the approval of the Condition Precedent Proposals. The transactions contemplated by the Merger Agreement will be consummated only if the Condition Precedent Proposals are approved at the extraordinary general meeting.

The approval of each of the Business Combination Proposal, the Director Election Proposal, the Stock Issuance Proposal, the Advisory Organizational Documents Proposals, and the Adjournment Proposal requires an Ordinary Resolution of the holders of ATII Ordinary Shares under the Companies Act and the Current Charter, being a resolution passed by the affirmative vote of a simple majority of the votes cast by holders of ATII Ordinary Shares, represented in person or, if proxies are allowed, by proxy and entitled to vote thereon at the extraordinary general meeting. The approval of each of the Domestication Merger Proposal and the Organizational Documents Proposal requires a Special Resolution of the holders of ATII Ordinary Shares under the Companies Act and the Current Charter, being a resolution passed by the affirmative vote of a majority of not less than two-thirds of the votes cast by holders of ATII Ordinary Shares, represented in person or, if proxies are allowed, by proxy and entitled to vote thereon at the extraordinary general meeting.

Only holders of record of ATII Ordinary Shares at the close of business on         , 2026 (the “Record Date”) are entitled to notice of the extraordinary general meeting or any adjournment, postponement or other delay thereof in accordance with the Companies Act and the Current Charter.

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The accompanying proxy statement/prospectus and accompanying proxy card is being provided to the holders of ATII Ordinary Shares in connection with the solicitation of proxies to be voted at the extraordinary general meeting and at any adjournment, postponement or other delay thereof.

Whether or not you plan to attend the extraordinary general meeting, all of the holders of ATII Ordinary Shares are urged to read the accompanying proxy statement/prospectus, including the Annexes and the documents referred to herein, carefully and in their entirety. You should also carefully consider the risk factors described under the heading “Risk Factors” beginning on page 65 of the accompanying proxy statement/prospectus.

The ATII Board unanimously recommends that you vote: (1) “FOR” the Business Combination Proposal; (2) “FOR” the Domestication Merger Proposal; (3) “FOR” the Director Election Proposal; (4) “FOR” the Stock Issuance Proposal; (5) “FOR” the Organizational Documents Proposal; (6) “FOR” the Advisory Organizational Documents Proposals; (7) “FOR” the Equity Incentive Plan Proposal; and (8) “FOR” the Adjournment Proposal. When you consider the recommendation of these proposals by the ATII Board, you should keep in mind that the ATII Directors and the officers of ATII have interests in the Business Combination that may conflict with the interests of holders of ATII Public Shares (as defined herein (each, an “ATII Public Shareholder”)). Additionally, the Sponsor and BTIG have the right to vote an aggregate of 6,590,000 ATII Ordinary Shares, or approximately 22.27% of the issued and outstanding ATII Ordinary Shares as of the Record Date and have agreed to vote any ATII Ordinary Shares held by them in favor of each proposal presented at the extraordinary general meeting. Accordingly, 8,205,001 additional votes of holders of ATII Ordinary Shares will be required to approve, by Ordinary Resolution of the holders of ATII Ordinary Shares, the Business Combination Proposal, the Director Election Proposal, the Stock Issuance Proposal, the Advisory Organizational Documents Proposals, the Equity Incentive Plan Proposal and, if presented, the Adjournment Proposal, while 13,136,667 additional votes of the holders of ATII Ordinary Shares will be required to approve, by Special Resolution of the holders of ATII Ordinary Shares, the Domestication Merger Proposal and the Organizational Documents Proposal. See “Proposal No. 1 – The Business Combination Proposal — Certain Interests of ATII’s Directors and Officers and Others in the Business Combination” for a further discussion of these considerations.

Pursuant to the Current Charter, an ATII Public Shareholder may elect to have ATII redeem all or a portion of the ATII Public Shares held by such ATII Public Shareholder in exchange for cash if the Business Combination (or any other initial business combination) is consummated during the Completion Window. If the Business Combination is approved and completed during the Completion Window, an ATII Public Shareholder will be entitled to receive cash in exchange for any ATII Public Shares held by such ATII Public Shareholder only if:

ATII Public Shareholders must complete the procedures for electing to redeem their ATII Public Shares in the manner described above prior to          Eastern Time on         , 2026 (up to two (2) business days prior to the initially scheduled vote on the Business Combination Proposal and the other proposals included in this proxy statement/prospectus) in order for their ATII Public Shares to be redeemed. Holders of ATII Public Units must elect to separate any ATII Public Units held by them into the underlying ATII Public Shares and ATII Public Warrants prior to exercising their redemption rights with respect to the ATII Public Shares. ATII Public Shareholders may elect to redeem their ATII Public Shares even if they vote “FOR” the Business Combination Proposal. If the Business Combination (or any other initial business combination) is not consummated during the Completion Window, the ATII Public Shares will be returned to their respective holder, broker or bank.

If the Business Combination (or any other initial business combination) is consummated during the Completion Window, and if any ATII Public Shareholder properly exercises their right to redeem all or a portion of the ATII Public Shares that they hold and timely tenders or delivers its ATII Public Share certificates (if any) and other redemption forms (as applicable) to the Transfer Agent, ATII will redeem such ATII Public Shares for a per-share price, payable in cash, equal to quotient obtained by dividing (1) the

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aggregate amount then on deposit in the Trust Account calculated as of two business days prior to the consummation of the Business Combination (or any other initial business combination) during the Completion Window, including interest earned on the Trust Account (net of taxes paid or payables), by (2) the aggregate number of ATII Public Shares then issued and outstanding. For illustrative purposes, as of December 31, 2025, this would have amounted to approximately $10.43 per issued and outstanding ATII Public Share. If any ATII Public Shareholder exercises their redemption rights in full, then they will be electing to exchange all of their ATII Public Shares in exchange for cash and will thereafter no longer own ATII Public Shares. See “Extraordinary General Meeting of ATII — Redemption Rights” for a detailed description of the procedures to be followed if you wish to redeem your ATII Public Shares in exchange for cash.

Notwithstanding the foregoing, pursuant to the Current Charter, any ATII Public Shareholder, together with any affiliate of such ATII Public Shareholder or any other person with whom such ATII Public Shareholder is acting in concert or as a “group” (as defined in Section 13(d)(3) of the Securities Exchange Act of 1934, as amended (the “Exchange Act”)), will be restricted from redeeming its ATII Public Shares with respect to more than an aggregate of 15% of the ATII Public Shares then issued and outstanding without ATII’s prior consent. Accordingly, if any ATII Public Shareholder, alone or acting in concert or as a “group,” seeks to redeem more than an aggregate of 15% of the ATII Public Shares then issued and outstanding, then any such ATII Public Shares in excess of that 15% limit would not be redeemed without ATII’s prior consent.

The Merger Agreement is subject to the satisfaction or waiver of customary closing conditions, including, among others: (a) approval of the Business Combination and related agreements and transactions by the respective shareholders of ATII and Forge Nano; (b) the effectiveness of the registration statement on Form S-4 filed by ATII and Forge Nano of which the accompanying proxy statement/prospectus forms a part; and (c) the Pubco Common Stock being approved for listing on Nasdaq. Conditions (a) through (c) above are subject to waiver (where permissible) if such waiver is agreed by all parties to the Merger Agreement. The Maximum Redemptions Scenario presented throughout the accompanying proxy statement/prospectus reflects the redemption of 100% of the ATII Public Shares that are not subject to non-redemption agreements.

The Sponsor, ATII Directors and officers of ATII (collectively, the “Insiders”) and BTIG each agreed to, among other things, vote in favor of the Business Combination Proposal and the other proposals included in the accompanying proxy statement/prospectus, and to waive their redemption rights in connection with the consummation of the Proposed Transaction with respect to any ATII Ordinary Shares held by them as of immediately prior to the Domestication Merger Effective Time. Such redemption rights waiver was provided in connection with the IPO and without any separate consideration paid in connection with providing such waiver. The Sponsor, which includes among its members each of the ATII Directors and each of the officers of ATII, and BTIG collectively own 6,590,000 ATII Ordinary Shares. As a result, as of the date of the accompanying proxy statement/prospectus, the Insiders and BTIG own approximately 22.27% of the issued and outstanding ATII Ordinary Shares. Accordingly, 8,205,001 additional votes of holders of ATII Ordinary Shares will be required to approve, by Ordinary Resolution of the holders of ATII Ordinary Shares, the Business Combination Proposal, the Director Election Proposal, the Stock Issuance Proposal, the Advisory Organizational Documents Proposals, the Equity Incentive Plan Proposal and, if presented, the Adjournment Proposal, while 13,136,667 additional votes of holders of ATII Ordinary Shares will be required to approve, by Special Resolution of the holders of ATII Ordinary Shares, the Domestication Merger Proposal and the Organizational Documents Proposal.

Whether or not you plan to attend the extraordinary general meeting, please sign, date and return, as promptly as possible, the enclosed proxy card in the accompanying prepaid reply envelope or grant your proxy electronically over the Internet or by telephone (in accordance with the instructions detailed in the section of the accompanying proxy statement/prospectus entitled “Extraordinary General Meeting of ATII – Voting Power”). If you attend and vote at the extraordinary general meeting, your vote will revoke any proxy that you have previously submitted. If you hold your ATII Ordinary Shares in “street name”, you should instruct your bank, broker or other nominee how to vote your ATII Ordinary Shares in accordance with the voting instruction form that you will receive from your bank, broker or other nominee. Your bank, broker or other nominee cannot vote on any of the proposals, including the Business Combination Proposal, without your instructions. If you sign, date and mail your proxy card without indicating how you wish to vote, your proxy will be counted as a vote “FOR” the Business Combination Proposal and “FOR” all other proposals presented to the holders of ATII Ordinary Shares in the accompanying proxy statement/prospectus. The transactions contemplated by the Merger Agreement will be consummated only if the Condition Precedent Proposals are approved at the extraordinary general meeting.

Your attention is directed to the proxy statement/prospectus following this notice (including the Annexes and other documents referred to herein) for a more complete description of the Business Combination and related transactions and each of the proposals presented to the holders of ATII Ordinary Shares in the accompanying proxy statement/prospectus. You are encouraged to read the accompanying proxy statement/prospectus carefully and in its entirety, including the Annexes and other documents referred to herein.

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If you have any questions or need assistance voting your ATII Ordinary Shares, please contact           , our proxy solicitor, by email at           . Individuals may also call           toll free at          ; banks and brokers can call          . This notice of extraordinary general meeting and the proxy statement/prospectus are available at          .

Thank you for your participation. We look forward to your continued support.

By Order of the Board of Directors of Archimedes Tech SPAC Partners II Co.

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FOR ANY ATII PUBLIC SHAREHOLDER TO EXERCISE ITS REDEMPTION RIGHTS, AT LEAST TWO BUSINESS DAYS PRIOR TO THE INITIALLY SCHEDULED VOTE ON THE BUSINESS COMBINATION PROPOSAL AT THE EXTRAORDINARY GENERAL MEETING, SUCH ATII PUBLIC SHAREHOLDER MUST (1) IF SUCH ATII PUBLIC SHAREHOLDER HOLDS ATII PUBLIC SHARES AS PART OF ATII PUBLIC UNITS, ELECT TO SEPARATE ITS ATII PUBLIC UNITS INTO THE UNDERLYING ATII PUBLIC SHARES AND ATII PUBLIC WARRANTS PRIOR TO SUCH ATII PUBLIC SHAREHOLDER EXERCISING ITS REDEMPTION RIGHTS WITH RESPECT TO THE ATII PUBLIC SHARES, (2) SUBMIT A WRITTEN REQUEST, INCLUDING THE NAME, PHONE NUMBER, AND ADDRESS OF THE BENEFICIAL OWNER OF THE ATII PUBLIC SHARES FOR WHICH REDEMPTION IS REQUESTED, TO THE TRANSFER AGENT THAT ITS ATII PUBLIC SHARES BE REDEEMED IN EXCHANGE FOR CASH AND (3) DELIVER ITS ATII PUBLIC SHARES ALONG WITH ANY REDEMPTION FORMS TO THE TRANSFER AGENT, PHYSICALLY OR ELECTRONICALLY USING THE DTC’S DWAC (DEPOSIT WITHDRAWAL AT CUSTODIAN) SYSTEM, IN EACH CASE IN ACCORDANCE WITH THE PROCEDURES AND DEADLINES DESCRIBED IN THE ACCOMPANYING PROXY STATEMENT/PROSPECTUS. IF ANY ATII PUBLIC SHAREHOLDER HOLDS ITS ATII PUBLIC SHARES IN “STREET NAME”, SUCH ATII PUBLIC SHAREHOLDER WILL NEED TO INSTRUCT THE ACCOUNT EXECUTIVE AT ITS BANK, BROKER OR OTHER NOMINEE TO WITHDRAW THE ATII PUBLIC SHARES FROM ITS ACCOUNT IN ORDER TO EXERCISE SUCH ATII PUBLIC SHAREHOLDER’S REDEMPTION RIGHTS WITH RESPECT TO SUCH ATII PUBLIC SHARES. IF THE BUSINESS COMBINATION (OR ANY OTHER INITIAL BUSINESS COMBINATION) IS NOT CONSUMMATED DURING THE COMPLETION WINDOW, THEN THESE ATII PUBLIC SHARES WILL BE RETURNED TO SUCH ATII PUBLIC SHAREHOLDER OR SUCH ATII PUBLIC SHAREHOLDER’S ACCOUNT.

The accompanying proxy statement/prospectus is dated          , 2026 and is first being mailed to holders of ATII Ordinary Shares on or about          , 2026.

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ABOUT THIS PROXY STATEMENT/PROSPECTUS

This proxy statement/prospectus forms part of a registration statement on Form S-4 filed with the Securities and Exchange Commission (the “SEC”) by ATII Holdings, Inc., a Delaware corporation (“Pubco”) and Forge Nano, Inc., a Delaware corporation (“Forge Nano”). It constitutes a prospectus of Pubco and Forge Nano under Section 5 of the Securities Act, with respect to the shares of Pubco Common Stock and Pubco Warrants to be issued if the Business Combination (as defined herein) is consummated. It also constitutes a proxy statement of Archimedes Tech SPAC Partners II Co., a Cayman Islands exempted company (“ATII”) under Section 14(a) of the Exchange Act, and a notice of meeting with respect to the extraordinary general meeting of holders of ATII Ordinary Shares (the “extraordinary general meeting”) at which holders of ATII Ordinary Shares will be asked to consider and vote, among other matters, upon a proposal to approve, by Ordinary Resolution of the holders of ATII Ordinary Shares, the Business Combination Proposal.

The extraordinary general meeting will be held via live webcast on           , 2026, beginning at            Eastern Time (unless the extraordinary general meeting is adjourned or postponed). Holders of ATII Ordinary Shares will be able to virtually attend and vote at the extraordinary general meeting by visiting           .

You should rely only on the information contained in this proxy statement/prospectus. ATII and Forge Nano have not authorized anyone to provide you with information that is different from that contained in this proxy statement/prospectus. This proxy statement/prospectus is dated           , 2026, and you should not assume that the information contained in this proxy statement/prospectus is accurate as of any date other than such date unless otherwise specifically provided herein.

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 to or from any person to whom it is unlawful to make any such offer or solicitation in such jurisdiction.

This proxy statement/prospectus incorporates important business and financial information about ATII that is not included in or delivered with this proxy statement/prospectus. You may request copies of this proxy statement/prospectus, without charge, by written request to ATII’s Chief Executive Officer at 2093 Philadelphia Pike #1968, Claymont, DE 19703; or to           , our proxy solicitor, by email at           . Individuals may also call            toll free at           ; banks and brokers can call           . You may also access copies of this proxy statement/prospectus or any of the documents incorporated by reference into this proxy statement/prospectus through the SEC website at www.sec.gov.

In order for you to receive timely delivery of the documents in advance of the extraordinary general meeting, you must request the information by           , 2026, which is five business days prior to the date of the extraordinary general meeting.

This proxy statement/prospectus is first being mailed to holders of ATII Ordinary Shares, holders of ATII Warrants and the Forge Nano Stockholders who receive Closing Payment Shares and the holders of Pubco Convertible Securities issued in exchange for Forge Nano Convertible Securities in accordance with and subject to the terms and conditions of the Merger Agreement (as defined below), on or about           , 2026. Throughout this proxy statement/prospectus, we refer to ATII Merger Sub Inc., a Delaware corporation, as “Merger Sub I”, ATII Merger Sub II, LLC, a Delaware limited liability company, as “Merger Sub II” and ATII, Pubco, Forge Nano, Merger Sub I and Merger Sub II each as a “party” and together as the “parties.” In addition, throughout this proxy statement/prospectus, we refer to the Agreement and Plan of Merger, dated as of April 20, 2026 (as it may be amended from time to time), by and among ATII, Pubco, Merger Sub I, Merger Sub II and Forge Nano as the “Merger Agreement.” Unless indicated otherwise, any other capitalized term used herein but not defined herein has the meaning assigned to such term in the Merger Agreement.

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FREQUENTLY USED TERMS

Unless otherwise stated or unless the context otherwise requires, the terms “we,” “us,” “our,” and “ATII” refer to Archimedes Tech SPAC Partners II Co. (which, prior to the Domestication Merger Effective Time, is an exempted company incorporated under the laws of the Cayman Islands and, which, by virtue of the Domestication Merger, will merge with and into ATII Holdings, Inc., a Delaware corporation and wholly-owned subsidiary of ATII (“Pubco”), following which the separate corporate existence of ATII will cease to exist and Pubco will continue as the surviving corporation incorporated under the laws of the State of Delaware pursuant to the Companies Act and DGCL). Upon the Domestication Merger Effective Time, Pubco will be renamed “Forge Nano Holdings Inc.”

In this document:

“25% Redemptions Scenario” means a redemptions scenario that assumes that 5,750,000 ATII Public Shares, or 25% of the outstanding ATII Public Shares and 25% of all ATII Public Shares that are not subject to non-redemption agreements, are redeemed by ATII Public Shareholders in connection with the Business Combination.

“50% Redemptions Scenario” means a redemptions scenario that assumes that 11,500,000 ATII Public Shares, or 50% of the outstanding ATII Public Shares and 50% of all ATII Public Shares that are not subject to non-redemption agreements, are redeemed by ATII Public Shareholders in connection with the Business Combination.

“75% Redemptions Scenario” means a redemptions scenario that assumes that 17,250,000 ATII Public Shares, or 75% of the outstanding ATII Public Shares and 75% of all ATII Public Shares that are not subject to non-redemption agreements, are redeemed by ATII Public Shareholders in connection with the Business Combination.

“A&R Registration Rights Agreement” means the Amended and Restated Registration Rights Agreement to be entered into by and among Pubco, the Sponsor, certain holders of Forge Nano Stock as of immediately prior to the First Effective Time and certain other investors, with effect upon completion of the Business Combination. A form of the A&R Registration Rights Agreement in substantially the form it will be executed in connection with Closing is attached to this proxy statement/prospectus as Annex E.

“Additional PIPE Warrants” means additional warrants to purchase 5,000,000 shares of Pubco Common Stock to be issued to the PIPE Investor if, on the 24-month anniversary of the Closing, the PIPE Investor certifies in writing that it beneficially owns 5,000,000 shares of Pubco Common Stock.

“Adjournment Proposal” means the proposal to be considered at the extraordinary general meeting to adjourn the extraordinary general meeting to a later date or dates, if necessary to permit further solicitation and vote of proxies if it is determined by ATII that more time is necessary or appropriate to approve one or more proposals at the extraordinary general meeting.

“Advisory Organizational Documents Proposals” means, collectively, the proposals to be considered at the extraordinary general meeting to approve, on a non-binding advisory basis, certain material differences between the Current Charter and the Proposed Organizational Documents.

“Aggregate Fully Diluted Forge Nano Common Stock” means the number equal to the sum, without duplication, of (a) all shares of Forge Nano Common Stock that are issued and outstanding immediately prior to the First Effective Time, plus (b) the aggregate number of shares of Forge Nano Common Stock issuable upon conversion of all shares of Forge Nano Preferred Stock that are issued and outstanding immediately prior to the First Effective Time in connection with the Business Combination, plus (c) the aggregate number of shares of Forge Nano Common Stock issuable upon full conversion, exercise or exchange of any Forge Nano Warrants and Forge Nano Ascent Options that are outstanding and unexercised immediately prior to the First Effective Time.

“Ancillary Agreements” means each of the agreements and instruments contemplated by the Merger Agreement or otherwise related to the transactions contemplated by the Merger Agreement and such other agreements or instruments contemplated by the Merger Agreement, in each case that was executed and delivered on the date of the Merger Agreement or on or prior to the date of Closing by ATII, Pubco, Merger Sub I, Merger Sub II, the Sponsor, Forge Nano, the Persons who receive Closing Payment Shares and the holders of Pubco Convertible Securities issued in exchange for Forge Nano Convertible Securities in accordance with and subject to the terms and conditions of the Merger Agreement and/or any of their respective affiliates, including, among other things, the Proposed Charter, the Proposed Bylaws, the Purchaser Support Agreement, the Lock-Up Agreement, the A&R Registration Rights Agreement, the Pubco Ascent Warrant Agreement, and the Plan of Merger.

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“Assumed Redemption Price” means $10.43, the amount per ATII Public Share that ATII Public Shareholders would be entitled to receive upon exercise of their redemption rights if the date of redemption were December 31, 2025.

“ATII” or “Company” means Archimedes Tech SPAC Partners II Co. (which prior to the Domestication Merger Effective Time, is an exempted company incorporated under the laws of the Cayman Islands and, pursuant to the Domestication Merger, will merge with and into Pubco, following which the separate corporate existence of ATII will cease to exist and Pubco will continue as the surviving corporation incorporated under the laws of the State of Delaware pursuant to the Companies Act and the DGCL).

“ATII Board” means the board of directors of ATII prior to the Domestication Merger Effective Time and, following the Domestication Merger Effective Time but prior to the First Effective Time, the board of directors of Pubco.

“ATII Ordinary Shares” means the ordinary shares of ATII, par value $0.0001 per share.

“ATII Private Shares” means the ATII Ordinary Shares included in the ATII Private Units.

“ATII Private Units” means 840,000 private placement units of ATII sold in a private placement concurrently with the IPO, each unit consisting of one ATII Ordinary Share and one-half of one ATII Private Warrant. Of those 840,000 ATII Private Units, the Sponsor purchased 530,000 ATII Private Units and BTIG purchased 310,000 ATII Private Units.

“ATII Private Warrants” means the ATII Warrants issued as part of the ATII Private Units.

“ATII Public Shareholders” means the holders of ATII Public Shares.

“ATII Public Shares” means the ATII Ordinary Shares sold in the IPO (whether they were purchased in the IPO as part of the ATII Public Units or thereafter in the open market).

“ATII Public Units” means the units issued by ATII in the IPO (including pursuant to the overallotment option), each unit consisting of one ATII Ordinary Share and one-half of one ATII Warrant.

“ATII Public Warrants” means the ATII Warrants issued as part of the ATII Public Units.

“ATII Units” means, collectively, the ATII Public Units and the ATII Private Units.

“ATII Warrant Agreement” means the warrant agreement, dated as of February 10, 2025, between ATII and Odyssey Transfer and Trust Company, as warrant agent, which governs ATII’s outstanding warrants.

“ATII Warrants” means, collectively, the redeemable warrants issued as part of the ATII Units exercisable for one ATII Ordinary Share at an exercise price of $11.50 per share, subject to adjustment, pursuant to the terms of the ATII Warrant Agreement.

“BTIG” means BTIG, LLC.

“Business Combination Proposal” means the proposal to be considered at the extraordinary general meeting to approve the Merger Agreement and the transactions contemplated thereby, including the Business Combination and the Plan of Merger.

“Closing” means the closing of the Business Combination.

“Closing Date” means the date of the Closing.

“Closing Payment Shares” means such number of shares of Pubco Common Stock equal to (a)(i) $1,200,000,000 divided by (ii) $10.00 minus (b) the number of shares of Pubco Common Stock issuable upon exercise of any Pubco Convertible Securities issued in exchange for Forge Nano Convertible Securities, if any, pursuant to the Merger Agreement.

“Code” means the U.S. Internal Revenue Code of 1986, as amended.

“Companies Act” refers to the Companies Act (as revised) of the Cayman Islands.

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“Completion Window” means the period from ATII’s IPO to November 12, 2026 (or such later date that may be approved by holders of ATII Ordinary Shares).

“Condition Precedent Proposals” mean the Business Combination Proposal, the Domestication Merger Proposal, the Director Election Proposal, the Stock Issuance Proposal, the Organizational Documents Proposal and the Equity Incentive Plan Proposal.

“Current Charter” means ATII’s Amended and Restated Memorandum and Articles of Association in effect as of the date of this proxy statement/prospectus, as amended from time to time.

“Current Forge Nano Charter” means Forge Nano’s Sixth Amended and Restated Certificate of Incorporation in effect as of the date of this proxy statement/prospectus, as amended from time to time.

“DGCL” means the Delaware General Corporation Law, as amended.

“DLLCA” means the Delaware Limited Liability Company Act, as amended.

“Domestication Merger” means the statutory merger of ATII with and into Pubco pursuant to the terms of the Merger Agreement, upon which the separate existence of ATII will cease and Pubco will continue as the surviving corporation incorporated under the laws of the State of Delaware in accordance with the DGCL, the Companies Act, the certificate of merger filed with the Secretary of State of the State of Delaware, the Plan of Merger and the Current Charter.

“Domestication Merger Effective Time” means such time when the Plan of Merger is registered by the Cayman Registrar and when the certificate of merger is filed with the Secretary of State of the State of Delaware, or such later time as may be specified in the Plan of Merger and certificate of merger.

“Domestication Merger Proposal” means the proposal to be considered at the extraordinary general meeting to approve the Domestication Merger.

“DWAC” means DTC’s deposit/withdrawal at custodian system.

“Earn-Out Shares” means an aggregate amount of 90,000,000 shares of Pubco Common Stock, being the shares payable pursuant to Section 1.18(b) of the Merger Agreement.

“Effective Time” means the effective time of the Business Combination.

“Escrow Account” means a segregated escrow account holding, along with any other dividends, distributions or other income on the Earn-Out Shares pursuant to the Escrow Agreement between Purchaser, Pubco, the Company and the Escrow Agent.

“Escrow Agent” means Odyssey Transfer and Trust Company.

“Exchange Act” means the U.S. Securities Exchange Act of 1934, as amended.

“Excise Tax” means the 1% U.S. federal excise tax on certain repurchases (including redemptions) of stock by a publicly traded U.S. corporation.

“Exempt Issuance” means, with respect to the PIPE Subscription Agreement and PIPE Warrant Certificate, issuances of securities (i) to employees, directors and officers, and other agents of Pubco pursuant to certain share or adoption plans, (ii) pursuant to the Merger Agreement, (iii) to certain specified investors prior to the Closing in an aggregate amount up to $60,000,000, (iv) with respect to the shares underlying the PIPE Warrants or (v) pursuant to any merger, acquisition or strategic transaction, subject to certain limitations.

“extraordinary general meeting” means the extraordinary general meeting of holders of ATII Ordinary Shares, to be held virtually at            Eastern Time on         , 2026, via live webcast at         , and any adjournments or postponements thereof.

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“First Company Merger” means the statutory merger of Merger Sub I with and into Forge Nano pursuant to the terms of the Merger Agreement, upon which the separate existence of Merger Sub I will cease and Forge Nano will continue as the “Initial Surviving Corporation” and a wholly-owned subsidiary of Pubco.

“First Effective Time” means the effective time of the First Company Merger.

“Forge Nano” means Forge Nano, Inc., a Delaware corporation, and, if the context requires, Forge Nano, Inc. together with its subsidiaries.

“Forge Nano Ascent Options” means, collectively, the options or other rights to acquire Forge Nano Securities held by Ascent Funds International Management LLC or its affiliates, including those specified in the Amended and Restated Consulting Agreement between Ascent Funds International Management LLC and Forge Nano dated September 1, 2025.

“Forge Nano Board” means the board of directors of Forge Nano as of immediately prior to the Closing.

“Forge Nano Common Stock” means the shares of common stock, $0.0001 par value per share, of Forge Nano.

“Forge Nano Convertible Securities” means, collectively, the Forge Nano Warrants and the Forge Nano Ascent Options.

“Forge Nano Lock-Up Holders” means, collectively, such stockholders of Forge Nano whose names appear on the signature pages to the Lock-Up Agreement and who are expected to collectively own approximately 53.15% of Pubco Common Stock at Closing assuming the No Additional Redemptions Scenario, or approximately 63.03% of Pubco Common Stock at Closing assuming the Maximum Redemptions Scenario.

“Forge Nano Option” means each option (whether vested or unvested) to purchase shares of Forge Nano Common Stock granted under the Forge Nano 2017 Equity Incentive Plan outstanding immediately prior to the First Effective Time.

“Forge Nano Preferred Stock” means, collectively, the Series A Preferred Stock, Series B Preferred Stock, Series C Preferred Stock and Series D Preferred Stock, par value $0.0001 per share, of Forge Nano.

“Forge Nano Stock” means any shares of the Forge Nano Common Stock and the Forge Nano Preferred Stock.

“Forge Nano Stockholder” means a holder of any shares of Forge Nano Stock as of immediately prior to the First Effective Time (excluding any holder of shares of Forge Nano Stock underlying any Forge Nano Options outstanding as of immediately prior to the First Effective Time).

“Forge Nano Warrants” means, collectively, the outstanding warrants to purchase shares of Forge Nano Stock outstanding as of immediately prior to the First Effective Time. Immediately following the First Effective Time, each Forge Nano Warrant will become a corresponding Pubco Forge Nano Warrant.

“Forge Nano Warrant Agreements” mean, collectively, each warrant agreement to purchase Forge Nano Warrants in effect as of immediately prior to the First Effective Time.

“Forge Nano Written Consent” means the written consent representing the requisite vote of the Forge Nano Stockholders (including any separate class or series vote(s) required pursuant to Forge Nano’s Organizational Documents, any stockholders agreement or otherwise), as necessary, to authorize, approve and consent to, the execution, delivery and performance of the Merger Agreement and each of the Ancillary Documents to which Forge Nano is or is required to be a party or bound, and the consummation of the transactions contemplated hereby and thereby, including the Company Merger (the “Required Forge Nano Stockholder Approval”), signed by Forge Nano’s key management members and the Significant Forge Nano Holders sufficient to approve the First Company Merger and the other transactions contemplated by the Merger Agreement.

“Founder Shares” means the 5,750,000 currently outstanding ATII Ordinary Shares purchased by the Sponsor in June 2024, prior to the IPO.

“GAAP” means U.S. generally accepted accounting principles.

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“IRS” means the U.S. Internal Revenue Service.

“Initial Shareholders” means, collectively, the Sponsor, the Insiders, each of their respective affiliates and representatives and certain other initial shareholders of ATII.

“Initial Surviving Corporation” means the surviving corporation pursuant to the First Company Merger.

“Insiders” means the Sponsor, each ATII Director and any officer of ATII.

“Insider Letter” means ATII’s letter agreement with the Insiders, dated February 10, 2025, containing provisions relating to transfer restrictions of the Founder Shares and ATII Private Units, indemnification of the Trust Account, waiver of Redemption Rights and participation in liquidation distributions from the Trust Account. No separate consideration was paid to the Insiders in connection with the waiver of Redemption Rights.

“IPO” means ATII’s initial public offering of the ATII Public Units (consisting of ATII Ordinary Shares and ATII Warrants) pursuant to registration statements on Form S-1 declared effective by the SEC on February 10, 2025 (SEC File No. 333-282885). On February 12, 2025, ATII completed its initial public offering.

“Lock-Up Agreement” means each lock-up agreement entered into by and among Pubco, Forge Nano and the Forge Nano Lock-Up Holders on or prior to the Closing. A form of the Lock-Up Agreement in substantially the form it will be executed in connection with Closing is attached to this proxy statement/prospectus as Annex D.

“Maximum Redemptions Scenario” means a redemptions scenario that assumes that 23,000,000 ATII Public Shares, or 100% of the outstanding ATII Public Shares and 100% of all ATII Public Shares that are not subject to non-redemption agreements, are redeemed in connection with the Business Combination.

“Merger Agreement” means the agreement and plan of merger, dated as of April 20, 2026, by and among ATII, Pubco, Merger Sub I, Merger Sub II and Forge Nano, and as it may be further amended and/or restated from time to time. A copy of the Merger Agreement is attached to this proxy statement/prospectus as Annex A.

“Merger Sub I” means ATII Merger Sub Inc., a Delaware corporation and a wholly-owned subsidiary of ATII.

“Merger Sub II” means ATII Merger Sub II, LLC, a Delaware limited liability company and a wholly-owned subsidiary of ATII.

“Nasdaq” means The Nasdaq Stock Market LLC.

“No Additional Redemptions Scenario” means a redemptions scenario that assumes that none of the 23,000,000 ATII Public Shares, or 0% of the outstanding ATII Public Shares and 0% of all ATII Public Shares that are not subject to non-redemption agreements, are redeemed in connection with the Business Combination.

“Ordinary Resolution” means a resolution approved by a simple majority of the holders of ATII Ordinary Shares as, being entitled to do so, vote in person or, where proxies are allowed, by proxy at the extraordinary general meeting.

“Organizational Documents Proposal” means the proposal to be considered at the extraordinary general meeting to approve the Proposed Charter and the Proposed Bylaws. A copy of each of the Proposed Charter and the Proposed Bylaws is attached to this proxy statement/prospectus as Annex B-1 and Annex B-2, respectively.

“Person” means any individual, firm, corporation, partnership, limited liability company, association, trust, joint venture, joint stock company, governmental authority or instrumentality or other entity or organization of any other kind.

“PIPE Closing” means the closing of the PIPE Financing.

“PIPE Financing” means the financing transaction pursuant to which Pubco will, substantially concurrently with, and contingent upon, the consummation of the Business Combination, sell an aggregate of 10,000,000 shares of Pubco Common Stock and PIPE Warrants to purchase an aggregate of 15,000,000 shares of Pubco Common Stock to the PIPE Investor, for an aggregate purchase price of $100,000,000. Pursuant to the Purchaser Support Agreement, Sponsor has agreed to transfer 3,000,000 ATII Ordinary Shares

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to the PIPE Investor to the extent the PIPE Investor funds the PIPE Financing. In the event that on the 21^st trading day following the six-month anniversary of Closing, the VWAP (as defined in the PIPE Warrant Certificate) of the Pubco Common Stock is less than the Exercise Price (as defined in the PIPE Warrant Certificate), Pubco will issue to the PIPE Investor the Reset PIPE Warrants entitling the PIPE Investor to purchase up to 10,000,000 shares of Pubco Common Stock, in an amount equal to (i) the product of (x) 5,000,000, multiplied by (y) the Exercise Price then in effect divided by the PIPE Reset Price minus (ii) 5,000,000. In addition, if, on the 24-month anniversary of the Closing Date, the PIPE Investor certifies in writing that the PIPE Investor beneficially owns 5,000,000 shares of Pubco Common Stock, Pubco will issue to the PIPE Investor the Additional PIPE Warrants entitling the PIPE Investor to purchase 5,000,000 shares of Pubco Common Stock.

“PIPE Investor” means the person party to the PIPE Subscription Agreement as identified on the signature page thereto.

“PIPE Registration Statement” means the registration statement on Form S-1 to be filed pursuant to the PIPE Subscription Agreement, registering the resale of certain securities of Pubco.

“PIPE Reset Price” means the greater of (x) the VWAP (as defined in the Warrant Certificate) of the shares of Pubco Common Stock on the 21^st trading day following the six-month anniversary of Closing and (y)(A) if, as of the Closing, Pubco or any of its subsidiaries, including Forge Nano, is party to a binding agreement with a financing source reasonably acceptable to the PIPE Investor pursuant to which such financing source has committed to provide debt financing in amount at least equal to $200,000,000, subject only to customary funding conditions (as determined in good faith by Pubco), and such debt financing has been publicly disclosed prior to or in connection with the closing of the PIPE Financing, $7.28 or (B) otherwise, $5.00.

“PIPE Subscribed Shares” means the 10,000,000 shares of Pubco Common Stock to be issued to the PIPE Investor in connection with the PIPE Financing.

“PIPE Subscription Agreement” means the subscription agreement to purchase the PIPE Subscribed Shares and the PIPE Warrants, by and among ATII, Pubco, Forge Nano and the PIPE Investor.

“PIPE Warrant Certificate” means the warrant certificate representing the PIPE Warrants.

“PIPE Warrants” means the warrants to purchase shares of Pubco Common Stock to be issued to the PIPE Investor, each with an exercise price of $10.00 (subject to adjustments as described herein).

“Proposed Bylaws” mean the proposed bylaws of Pubco to be in effect following the Domestication Merger Effective Time and following the Business Combination, a copy of which is attached to this proxy statement/prospectus as Annex B-2.

“Proposed Charter” means the proposed certificate of incorporation of Pubco to be in effect at the Domestication Merger Effective Time and following the Business Combination, a copy of which is attached to this proxy statement/prospectus as Annex B-1.

“Proposed Organizational Documents” means, collectively, the Proposed Charter and the Proposed Bylaws.

“Proposed Transaction” or “Business Combination” means the transactions contemplated by the Merger Agreement and the other agreements contemplated therein.

“Pubco” means ATII Holdings Inc., a Delaware corporation and a wholly-owned subsidiary of ATII (which, upon effectiveness of the Domestication Merger, will be renamed “Forge Nano Holdings Inc.”).

“Pubco Ascent Warrants” means the Pubco Warrants issued to Ascent Funds International Management LLC or its affiliates pursuant to the Merger Agreement and the other agreements contemplated therein. A copy of the Pubco Ascent Warrant Agreement in substantially the form it will be executed in connection with Closing is attached to this proxy statement/prospectus as Annex F.

“Pubco Ascent Warrant Agreement” means the warrant agreement, dated as of the Closing Date, between Pubco and the holders party thereto, a copy of which is attached to this proxy statement/prospectus as Annex F, which will govern the Pubco Ascent Warrants following consummation of the Business Combination.

“Pubco Board” means the board of directors of Pubco subsequent to the Closing.

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“Pubco Common Stock” means the common stock of Pubco, par value $0.0001 per share.

“Pubco Convertible Securities” means, collectively, convertible securities of Pubco issued in exchange for the Forge Nano Convertible Securities pursuant to the Merger Agreement.

“Pubco Forge Nano Warrants” means, collectively, the following warrants (whether exercisable or unexercisable) to purchase shares of Pubco Common Stock following the Business Combination: (1) the penny warrant to purchase shares of Pubco Common Stock (the “Pubco OIC Penny Warrant”) issued in connection with Forge Nano’s credit facility, by and among Forge Nano, as borrower, the lenders from time to time party thereto, and OIC Investment Agent, LLC, as administrative agent and collateral agent (the “OIC Credit Facility”), (2) the warrant to purchase shares of Pubco Common Stock (the “Pubco OIC Company Warrant”) issued in connection with the OIC Credit Agreement, (3) the warrant to purchase shares of Pubco Common Stock issued to Silicon Valley Bank (the “Pubco SVB Warrant”) and (4) the warrant to purchase shares of Pubco Common Stock issued to Saoradh Energy Partners LLC (the “Pubco SEP Warrant”).

“Pubco Securities” means, collectively, shares of Pubco Common Stock and Pubco Warrants.

“Pubco SPAC Warrants” means the ATII Warrants that will become exercisable for shares of Pubco Common Stock subsequent to the Closing pursuant to the ATII Warrant Agreement.

“Pubco Warrants” means, collectively, (i) the Pubco SPAC Warrants, (ii) the Pubco Forge Nano Warrants, (iii) the Pubco Ascent Warrants and (iv) the PIPE Warrants.

“Purchaser Support Agreement” means the purchaser support agreement, dated as of April 20, 2026, entered into by and among ATII, Forge Nano and the Sponsor, as it may be amended and supplemented from time to time, pursuant to which the Sponsor has agreed, among other things, (i) not to transfer or redeem any ATII Ordinary Shares held by the Sponsor in accordance with the Insider Letter, (ii) to vote in favor of the Merger Agreement, the Domestication Merger and the Company Mergers at the extraordinary general meeting in accordance with the Insider Letter, (iii) to waive any anti-dilution or similar protection with respect to such ATII Ordinary Shares (whether resulting from the transactions contemplated by the Merger Agreement, by the Ancillary Documents or by any other transaction consummated in connection with the transactions contemplated thereby) and (iv) to contribute up to 3,300,000 Sponsor Contribution Shares to secure one or more Financing Transactions (as defined in the Purchaser Support Agreement) as follows: to the extent the PIPE Investors (as defined below) fund any Financing Transaction of at least $100,000,000, to transfer to such PIPE Investors 3,000,000 Sponsor Contribution Shares to secure such Financing Transaction and to transfer up to 300,000 Sponsor Contribution Shares to investors to secure other Financing Transactions to the extent such Financing Transactions are funded by such investors. A copy of the Purchaser Support Agreement is attached to this proxy statement/prospectus as Annex C.

“Record Date” means         , 2026.

“Redemption” means the redemption of ATII Public Shares by ATII for the Redemption Price in connection with its initial business combination.

“Redemption Price” means a per-ATII Public Share redemption price payable in cash equal to the quotient obtained by dividing (i) the aggregate amount then on deposit in the Trust Account, calculated as of two business days prior to the consummation of the Business Combination, including interest earned on the Trust Account (net of taxes paid or payable, if any), by the number of ATII Public Shares then in issue.

“Redemption Rights” means the rights of the ATII Public Shareholders to demand Redemption of their ATII Public Shares in exchange for cash in accordance with the procedures set forth in the Current Charter and this proxy statement/prospectus.

“Reset PIPE Warrants” means warrants to purchase shares of Pubco Common Stock to be issued to the PIPE Investor in the event that on the 21^st trading day following the six-month anniversary of Closing, the VWAP (as defined in the PIPE Warrant Certificate) of the Pubco Common Stock is less than the Exercise Price (as defined in the PIPE Warrant Certificate), in an amount equal to (i) the product of (x) 5,000,000, multiplied by (y) the Exercise Price then in effect divided by the PIPE Reset Price minus (ii) 5,000,000.

“Sarbanes-Oxley Act” means the Sarbanes-Oxley Act of 2002.

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“SEC” means the U.S. Securities and Exchange Commission.

“Second Company Merger” means the statutory merger of the Initial Surviving Corporation with and into Merger Sub II, upon which the separate corporate existence of the Initial Surviving Corporation will cease and Merger Sub II will continue as the surviving entity and a wholly-owned subsidiary of Pubco.

“Second Effective Time” means the effective time of the Second Company Merger.

“Securities Act” means the U.S. Securities Act of 1933, as amended.

“Shareholder Proposals” means, collectively, (a) the Business Combination Proposal, (b) the Domestication Merger Proposal, (c) the Director Election Proposal, (d) the Stock Issuance Proposal, (e) the Organizational Documents Proposal, (f) the Advisory Organizational Documents Proposals, (g) the Equity Incentive Proposal and (h) the Adjournment Proposal, if presented.

“Significant Forge Nano Holder” means, collectively, such stockholders of Forge Nano whose names appear on the signature pages to the Forge Nano Written Consent and who are expected to collectively own approximately 49.13% of Pubco Common Stock at Closing assuming the No Additional Redemptions Scenario, or approximately 58.26% of Pubco Common Stock at Closing assuming the Maximum Redemptions Scenario.

“Special Resolution” means a resolution passed by a majority of not less than two-thirds of the holders of ATII Ordinary Shares as, being entitled to do so, vote in person or, where proxies are allowed, by proxy at the extraordinary general meeting.

“Sponsor” means Archimedes Tech SPAC Sponsors II LLC, a Delaware limited liability company.

“Sponsor Contribution Shares” means up to 3,300,000 of the Founder Shares which are subject to transfer pursuant to the Purchaser Support Agreement.

“Stock Issuance Proposal” means the proposal to be considered at the extraordinary general meeting to approve for purposes of complying with the applicable provisions of Nasdaq Listing Rules 5635(a), (b) and (d), the issuance of shares of Pubco Common Stock and securities convertible into shares of Pubco Common Stock to (i) the Persons who receive Closing Payment Shares and the holders of Pubco Convertible Securities issued in exchange for Forge Nano Convertible Securities in accordance with and subject to the terms and conditions of the Merger Agreement, and (ii) to any other persons pursuant to subscription, purchase, or similar agreements ATII may enter into prior to Closing.

“Surviving Company” means the surviving company pursuant to the Second Company Merger.

“Transfer Agent” means Odyssey Transfer and Trust Company.

“Trust Account” means the trust account of ATII, which holds the net proceeds from the IPO and the sale of the ATII Private Units.

“Trust Agreement” means the Investment Management Trust Agreement, dated as of February 10, 2025, by and between ATII and the Transfer Agent, as trustee, as amended.

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MARKET AND INDUSTRY DATA

ATII and Forge Nano are responsible for the information contained in this proxy statement/prospectus. Certain industry data and market data contained in this proxy statement/prospectus were obtained from independent third-party surveys, market research, publicly available information, reports of governmental agencies and industry publications and surveys. All of Forge Nano’s management’s estimates presented herein concerning the market and the industry in which Forge Nano competes, including its market position, general expectations of market opportunity, size and growth rates, are based upon review of independent third-party surveys and industry publications prepared by a number of sources and other publicly available information. Third-party industry publications and forecasts generally state that the information contained therein has been obtained from sources generally believed to be reliable. All the industry data, market data and related estimates used in this proxy statement/prospectus involve a number of assumptions and limitations, and you are cautioned not to give undue weight to such data and estimates. Although we have no reason to believe that the information from these industry publications and surveys included in this proxy statement/prospectus is not reliable, we have not independently verified this information and cannot guarantee its accuracy or completeness. In addition, we believe that industry data, market data and related estimates provide general guidance but are inherently imprecise. The industry in which Forge Nano operates is subject to a high degree of uncertainty and risk due to a variety of factors, including those described in “Cautionary Note Regarding Forward-Looking Statements” and “Risk Factors — Risks Related to Forge Nano’s Business” and elsewhere in this proxy statement/prospectus. These and other factors could cause results to differ materially from those expressed in the estimates made by the independent parties and by us.

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TRADEMARKS

This document contains references to trademarks, trade names and service marks belonging to other entities. Solely for convenience, trademarks, trade names and service marks referred to in this proxy statement/prospectus may appear without the ®, TM or SM symbols, but such references are not intended to indicate, in any way, that the applicable licensor will not assert, to the fullest extent under applicable law, its rights to these trademarks and trade names. ATII and Forge Nano do not intend that use or display of other companies’ trade names, trademarks, or service marks to imply a relationship with, or endorsement or sponsorship of us, by any other companies.

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CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS

This proxy statement/prospectus contains “forward-looking statements” that involve substantial risks and uncertainties, including information about, among other topics, expectations for future financial performance, business strategies or expectations for Pubco’s business following the Proposed Transaction, and the timing and ability for ATII and Forge Nano to complete the Proposed Transaction. In addition, any statements that refer to projections, forecasts or other characterizations of future events or circumstances, including any underlying assumptions, are forward-looking statements. Such statements can be identified by the fact that they are not historical statements of fact and are statements regarding, but not limited to, our expectations, hopes, beliefs, intention or strategies regarding the future. When used in this proxy statement/prospectus, words such as “anticipate”, “believe”, “can”, “continue”, “could”, “estimate”, “expect”, “forecast”, “intend”, “may”, “might”, “plan”, “possible”, “potential”, “predict”, “project”, “seek”, “should”, “strive”, “target”, “will”, “would” and similar expressions may identify forward-looking statements, but the absence of these words does not mean that a statement is not forward-looking. Forward-looking statements are predictions, projections and other statements about future events that are based on current expectations and assumptions and, as a result, are subject to significant risks and uncertainties. Forward-looking statements speak only as of the date they are made. Readers are cautioned not to put undue reliance on forward-looking statements, and we assume no obligation and do not intend to update or revise these forward-looking statements, whether as a result of new information, future events or otherwise.

Forward-looking statements in this proxy statement/prospectus and in any document incorporated by reference in this proxy statement/prospectus may include information about, among other topics, that could cause actual results to differ materially from those expressed or implied by such statements:

Risks and uncertainties include, among other things:

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You should carefully consider the foregoing factors and the other risks and uncertainties that affect our business described in the section titled “Risk Factors” of this proxy statement/prospectus, in ATII’s registration statement on Form S-1 filed in connection with the IPO and in the “Cautionary Note Regarding Forward Looking Statements” and “Risk Factors” sections of ATII’s Annual Report on Form 10-K, Quarterly Reports on Form 10-Q, and other documents filed by ATII from time to time with the SEC, all of which are available at www.sec.gov. These filings identify and address other important risks and uncertainties that could cause actual events and results to differ materially from those contained in the forward-looking statements. Forward-looking statements speak only as of the date they are made. Readers are cautioned not to put undue reliance on forward-looking statements, and we do not assume any obligation to, and do not intend to, update or revise these forward-looking statements, whether as a result of new information, future events, or otherwise, unless required by law. We cannot give any assurance that we will achieve our expectations.

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QUESTIONS AND ANSWERS FOR SHAREHOLDERS OF ATII

The questions and answers address some commonly asked questions regarding the Business Combination and the Merger Agreement and the extraordinary general meeting. The following questions and answers may not address all questions that are important to you. You should carefully read this proxy statement/prospectus and annexes to this proxy statement/prospectus, including the Merger Agreement, along with all of the documents we refer to in this proxy statement/prospectus, as they contain important information about, among other things, the Business Combination and how the Business Combination may affect you. For the purposes of the Companies Act and the Current Charter, the physical location of the extraordinary general meeting will be at the offices of ATII at. To participate in the extraordinary general meeting online, visit         and enter the 12-digit control number included on your proxy card. You may register for the extraordinary general meeting as early as         Eastern Time on         , 2026. If you hold your ATII Ordinary Shares through a bank, broker or other nominee, you will need to take additional steps to participate in the extraordinary general meeting, as described in this proxy statement/prospectus.

Q.What is the proposed Business Combination?

Q.Why am I receiving this proxy statement/prospectus?

The ATII Board is soliciting your proxy to vote at the extraordinary general meeting because you are a holder of ATII Ordinary Shares. This proxy statement/prospectus, along with a proxy card or a voting instruction card, is being mailed to holders of ATII Ordinary Shares on or about            , 2026. Holders of ATII Ordinary Shares as of the close of business on            , 2026, the “Record Date” for the extraordinary general meeting, are entitled to notice of the extraordinary general meeting and to vote at the extraordinary general meeting. ATII has made these materials available to you on the Internet, and ATII has delivered printed proxy materials to you or sent them to you by e-mail. This proxy statement/prospectus summarizes the information that you need to know in order to cast your vote at the extraordinary general meeting. You do not need to attend the extraordinary general meeting in person to vote on your ATII Ordinary Shares.

The Business Combination cannot be completed unless the holders of ATII Ordinary Shares approve the Condition Precedent Proposals as set forth in this proxy statement/prospectus. Information about the extraordinary general meeting, the Business Combination and the other business to be considered by holders of ATII Ordinary Shares at the extraordinary general meeting is contained in this proxy statement/prospectus.

THE VOTE OF HOLDERS OF ATII ORDINARY SHARES IS IMPORTANT. HOLDERS OF ATII ORDINARY SHARES ARE ENCOURAGED TO VOTE AS SOON AS POSSIBLE AFTER CAREFULLY REVIEWING THIS PROXY STATEMENT/PROSPECTUS, INCLUDING THE ANNEXES AND THE ACCOMPANYING FINANCIAL STATEMENTS OF ATII AND FORGE NANO.

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Q.What am I being asked to vote on?

A.You are being asked to vote on the following proposals:

If the holders of ATII Ordinary Shares do not approve each of the Condition Precedent Proposals, then, unless certain conditions in the Merger Agreement are waived by all of the parties to the Merger Agreement, the Merger Agreement could be terminated and the Proposed Transaction may not be consummated. See “Proposal No. 1 – The Business Combination Proposal,” “Proposal No. 2 – The Domestication Merger Proposal,” “Proposal No. 3 – The Director Election Proposal,” “Proposal No. 4 – The Stock Issuance Proposal,” “Proposal No. 5 – The Organizational Documents Proposal” and “Proposal No. 7 – The Equity Incentive Plan Proposal” of this proxy statement/prospectus.

ATII will hold the extraordinary general meeting to consider and vote upon these proposals. This proxy statement/prospectus contains important information about the Business Combination and the other matters to be acted upon at the extraordinary general meeting. Holders of ATII Ordinary Shares should read it carefully.

After careful consideration, the ATII Board has determined that each of (a) the Business Combination Proposal, (b) the Domestication Merger Proposal, (c) the Director Election Proposal, (d) the Stock Issuance Proposal, (e) the Organizational Documents Proposal, (f) the Advisory Organizational Documents Proposals, (g) the Equity Incentive Plan Proposal and (h) the Adjournment Proposal, if presented, are in the best interests of ATII and the holders of ATII Ordinary Shares and unanimously recommends that you vote or give instruction to vote “FOR” each of those proposals.

The existence of financial and personal interests of one or more ATII Directors may result in a conflict of interest on the part of such ATII Director(s) between what he, she or they may believe is in the best interests of ATII and the holders of ATII Ordinary Shares and what he, she or they may believe is best for himself, herself or themselves in determining to recommend that holders of ATII Ordinary Shares vote for the proposals. In addition, ATII’s officers have interests in the Proposed Transaction that may conflict with your interests as a holder of ATII Ordinary Shares. See “Proposal No. 1 – The Business Combination Proposal — Certain Interests of ATII’s Directors and Officers and Others in the Business Combination” for a further discussion of these considerations.

Q.May I attend and vote at the extraordinary general meeting?

ATII Ordinary Shares held directly in your name as a holder of record may be voted at the extraordinary general meeting via the extraordinary general meeting website, provided you have pre-registered for the extraordinary general meeting. ATII Ordinary

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Shares held in “street name” may be voted at the extraordinary general meeting via the extraordinary general meeting website only if you obtain a legal proxy from your bank, broker or other nominee and provided you have pre-registered for the extraordinary general meeting.

Even if you attend the extraordinary general meeting, we encourage you to sign, date and return the enclosed proxy card in the accompanying prepaid reply envelope or grant your proxy electronically over the internet or by telephone (in accordance with the instructions in this proxy statement entitled “Extraordinary General Meeting of ATII – Voting Power”) so that your vote will be counted if you later decide not to, or become unable to, virtually attend the extraordinary general meeting. If you attend and vote at the extraordinary general meeting, your vote will revoke any proxy previously submitted.

Q.Are the proposals conditioned on one another?

Q.Why is ATII proposing the Business Combination?

On February 10, 2025, ATII completed its IPO, generating gross proceeds of $231,150,000, which were placed in the Trust Account. All of ATII’s activity since its IPO has been related to identifying an appropriate target company for a potential business combination and negotiating for an initial business combination. Based on its due diligence investigations of Forge Nano and the industry in which Forge Nano operates, including the financial and other information provided by Forge Nano in the course of due diligence and the negotiations of the Merger Agreement, ATII believes that Forge Nano aligns well with the objectives laid out in ATII’s investment thesis. As a result, consistent with its proposed business at the time of its IPO, ATII believes that a business combination with Forge Nano will provide holders of ATII Ordinary Shares with an opportunity to participate in the ownership of a publicly-listed company with significant growth potential in an alternative industry with a clear path to generating cash flow and growth. See the section titled “Proposal No. 1 – The Business Combination Proposal – ATII Board Reasons for the Approval of the Business Combination.”

Although the ATII Board believes that the Proposed Transaction presents an attractive business combination opportunity and is in the best interests of ATII and the holders of ATII Ordinary Shares, the ATII Board also considered certain potentially material negative factors in arriving at that conclusion. These factors are discussed in greater detail in “Proposal No. 1 – The Business Combination Proposal – ATII Board Reasons for the Approval of the Business Combination” and “Risk Factors – Risks Related to Forge Nano’s Business.”

Q.What will I receive if the Business Combination is consummated?

At the Domestication Merger Effective Time, holders of ATII Ordinary Shares will be entitled to receive, after giving effect to redemptions of ATII Public Shares occurring prior to the Domestication Merger Effective Time, without interest and less any applicable withholding taxes (if any), for each ATII Ordinary Share that you own and that is issued and outstanding immediately prior to the Domestication Merger Effective Time, one share of Pubco Common Stock. In addition, each ATII Warrant that is unexercised immediately prior to the Domestication Merger Effective Time shall become one Pubco SPAC Warrant subject to the conditions set forth in the ATII Warrant Agreement.

At the First Effective Time, holders of Forge Nano Preferred Stock and Forge Nano Common Stock will be entitled to receive the Applicable Per Share Merger Consideration, while holders of Forge Nano Convertible Securities will be entitled to receive corresponding Pubco Convertible Securities. In addition, the Persons who receive Closing Payment Shares and the holders of

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Pubco Convertible Securities issued in exchange for Forge Nano Convertible Securities will be entitled to receive, a proportional amount of the Earn-Out Shares, issuable upon achievement of certain milestones during the Earn-Out Period.

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The following table illustrates varying ownership levels of Pubco immediately following the Business Combination on a fully diluted basis⁽¹⁾:

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