UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934

Date of Report (Date of earliest event reported) October 26, 2026

RadNet, Inc.

(Exact name of registrant as specified in its charter)

(310) 478-7808

(Registrant’s Telephone Number, Including Area Code)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

Securities registered pursuant to Section 12(b) of the Act:

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ☐

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 13(a) of the Exchange Act. ☐

Item 1.01 Entry into a Material Definitive Agreement.

Merger Agreement

On October 26, 2026, RadNet, Inc., a Delaware corporation (the “Company,” “RadNet,” “we,” and “us”), and Radnet Management, Inc., a California corporation and direct wholly owned subsidiary of the Company (“Purchaser”), entered into an Agreement and Plan of Merger (the “Merger Agreement”) with OnRad, Inc., a Delaware corporation (“OnRad”), Red Rover Merger Sub, LLC, a Delaware limited liability company and direct wholly owned subsidiary of Purchaser (the “Surviving Merger Sub”), Javelin Merger Sub, Inc., a Delaware corporation and direct wholly owned subsidiary of the Surviving Merger Sub (the “First Merger Sub,” and together with Surviving Merger Sub, the “Merger Subs”), and, solely for purposes of the specified provisions therein, Housatonic IV CF, L.P., a Delaware limited partnership, solely in its capacity as the securityholder representative (“Securityholder Representative”).

Pursuant to the Merger Agreement, and subject to the terms and conditions set forth therein, (a) First Merger Sub will merge with and into OnRad, with OnRad surviving the First Merger as a direct wholly owned subsidiary of Surviving Merger Sub (the “First Merger”), and (b) immediately thereafter, OnRad will merge with and into Surviving Merger Sub, with Surviving Merger Sub surviving the Second Merger as a direct wholly owned subsidiary of Purchaser (the “Second Merger,” and, together with the First Merger, the “Mergers”).

At the closing of the Mergers (the “Closing”), the holders (the “OnRad Holders”) of OnRad’s common stock, par value $0.0001 per share (the “OnRad Common Stock”) (including any then outstanding shares of OnRad Common Stock into which the holders of OnRad’s outstanding preferred stock and warrants have converted in accordance with the Merger Agreement, but in all cases excluding Dissenting Shares (as defined in the Merger Agreement)) and the holders of Vested Company Options (as defined in the Merger Agreement) will receive an aggregate of (i) $350,000,000 in cash, subject to customary adjustments for cash, indebtedness, net working capital and transaction expenses and subject to certain escrow holdbacks, and (ii) 5,000,000 shares (the “Closing Shares”) of common stock of the Company, par value $0.0001 per share (the “RadNet Common Stock”).

In addition, the OnRad Holders may also be entitled to an earn-out payment of up to $210,000,000 (the “Earn-Out Amount”) if OnRad achieves a certain target Post-Closing Annual Adjusted EBITDA (as defined in the Merger Agreement) for the fiscal year ending December 31, 2027. The Earn-Out Amount may be paid in cash, shares of RadNet Common Stock (the “Earn-Out Shares”) or a combination thereof subject to certain tax-related requirements.

Pursuant to the Merger Agreement, the Company has agreed to file prospectus supplements to its automatic shelf registration statement on Form S-3 (Registration No. 333-291945) (the “Registration Statement”) to register the resale of the Closing Shares and, if any, the Earn-Out Shares, within three (3) business days following the Closing and the Earn-Out Amount Determination Date (as defined in the Merger Agreement), respectively.

The Mergers are expected to close in early 2027, subject to customary closing conditions, including, but not limited to, (i) the making or receipt of certain state healthcare regulatory filings and approvals; (ii) the absence of any law or order prohibiting the Mergers; (iii) the delivery of the written consent of OnRad’s stockholders approving the Merger Agreement and the transactions contemplated thereunder (the “Required Stockholder Approval”); (iv) David M. Engert, who is currently serving as OnRad’s President and Chief Executive Officer, remaining employed by OnRad through the Closing and not having revoked, rescinded or repudiated that certain Employment Agreement entered into between OnRad and Mr. Engert on October 26, 2026, which will become effective at, and is contingent upon, the Closing; (v) the conveyance of all ownership interests in each of OnRad’s contracted professional entities to a physician designated by Purchaser; and (vi) the effectiveness of the Registration Statement. The Merger Agreement may be terminated under certain circumstances, including by either party if the Mergers have not been consummated by February 23, 2027 (which date automatically extends to June 1, 2027 if the only unsatisfied closing condition is the receipt of the required governmental and regulatory filings and approvals), and by Purchaser if the Required Stockholder Approval is not timely delivered. The parties previously filed under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended, and the waiting period has expired.

The parties to the Merger Agreement have made customary representations and warranties in the Merger Agreement. The Merger Agreement also contains certain other customary covenants and agreements.

The foregoing description of the Merger Agreement is not complete and is qualified in its entirety by reference to the Merger Agreement, which is attached as Exhibit 2.1 to this Current Report on Form 8-K and incorporated by reference herein. The Merger Agreement and the foregoing description of such agreement have been included to provide investors and stockholders with information regarding the terms of such agreement. The assertions embodied in the representations and warranties contained in the Merger Agreement are qualified by information in confidential disclosure schedules delivered by OnRad to Purchaser in connection with the signing of the Merger Agreement. Moreover, certain representations and warranties in the Merger Agreement were made as of a specified date, may be subject to a contractual standard of materiality different from what might be viewed as material to stockholders, or may have been used for the purpose of allocating risk between the parties to the Merger Agreement. Accordingly, the representations and warranties in the Merger Agreement should not be relied on by any persons as characterizations of the actual state of facts and circumstances of OnRad or the Company, as applicable, at the time they were made and investors should consider the information in the Merger Agreement in conjunction with the entirety of the factual disclosure about the Company in its public reports filed with the Securities and Exchange Commission. Information concerning the subject matter of the representations and warranties may change after the date of the Merger Agreement, which subsequent information may or may not be fully reflected in the Company’s public disclosures.

Restrictive Covenant and Support Agreement

In connection with the execution of the Merger Agreement, Purchaser, OnRad and each of certain stockholders of OnRad (collectively, the “RCS Stockholders”), entered into that certain Restrictive Covenant and Support Agreement, dated October 26, 2026 (collectively, the “RCS Agreements”), substantially in the form attached to the Merger Agreement and filed as Exhibit 10.1 to this Current Report on Form 8-K. The restrictive covenants and lock-up provisions of the RCS Agreements will become effective at the Closing and the remaining provisions become effective upon execution.

Under the RCS Agreements, the RCS Stockholders made customary representations regarding its ownership of OnRad securities and agreed, among other things, to (i) non-competition covenant with respect to the provision of teleradiology services in the United States; (ii) non-solicitation and no-hire covenants with respect to OnRad’s employees and business relationships; (iii) a lock-up on transfers of the Closing Shares during specified periods); (iv) confidentiality and non-disparagement obligations; and (v) a general release of claims against OnRad, effective following the Closing.

The foregoing description of the RCS Agreements is a summary only and is qualified in its entirety by reference to the full text of the form of RCS Agreement, which is filed as Exhibit 10.1 to this Current Report on Form 8-K and incorporated by reference into this Item 1.01 in its entirety.

Item 3.02 Unregistered Sales of Equity Securities.

The information set forth under the caption “Merger Agreement” in Item 1.01 of this Current Report on Form 8-K is incorporated by reference into this Item 3.02.

The Closing Shares and any Earn-Out Shares to be issued as consideration under the Merger Agreement will be issued in reliance on the exemption from registration provided by Section 4(a)(2) of the Securities Act of 1933, as amended (the “Securities Act”), and/or Rule 506 of Regulation D promulgated thereunder.

Item 7.01 Regulation FD Disclosure.

On October 26, 2026, the Company issued a press release announcing the entry into the Merger Agreement. A copy of the press release is furnished herewith as Exhibit 99.1.

The Company will host a webcast and conference call at 8:00 A.M. (Eastern Daylight Time) on Tuesday, October 27, 2026 to discuss the transaction.

The information in this Item 7.01 and Exhibit 99.1 hereto (i) is furnished pursuant to Item 7.01 and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liability of such section; and (ii) shall not be deemed incorporated by reference into any filing under the Securities Act or the Exchange Act, except as expressly set forth by specific reference in such filing.

Item 9.01 Financial Statements and Exhibits.

(d) Exhibits.

* Filed herewith.

** Furnished herewith.

# Certain schedules and exhibits have been omitted pursuant to Item 601(a)(5) and/or Item 601(b)(2) of Regulation S-K. The Company agrees to furnish supplementally a copy of such schedules and exhibits, or any section thereof, to the U.S. Securities and Exchange Commission (the “SEC”) upon request; provided, however, that the Company may request confidential treatment pursuant to Rule 24b-2 under the Exchange Act for any exhibits or schedules so furnished.

Cautionary Note Regarding Forward-Looking Statements

This Current Report on Form 8-K, including the exhibits hereto, includes “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995, Section 27A of the Securities Act and Section 21E of the Exchange Act. All statements, other than statements of historical fact, included in this Current Report on Form 8-K that address activities, events or developments that the Company expects, believes or anticipates will or may occur in the future are forward-looking statements. Terminology such as “could,” “believe,” “anticipate,” “intend,” “estimate,” “expect,” “may,” “continue,” “predict,” “potential,” “project” and similar expressions are intended to identify forward-looking statements. These statements include, but are not limited to, statements regarding the Mergers, the expected timing and completion of the Mergers, the anticipated benefits of the Mergers, the potential Earn-Out Amount, the expected financial impact of the Mergers on the Company and other statements that are not historical facts. Forward-looking statements are based on current plans, estimates, expectations and assumptions as of the time they are made, are not guarantees of future performance and should not be relied on as predictions of future events, and there can be no assurance that such estimates, assumptions and expectations will prove to have been correct. These forward-looking statements involve risks and uncertainties, many of which are difficult to predict and are generally outside the Company's control, and other factors that could cause the Company’s actual results or financial condition to differ materially from those expressed or implied by forward-looking statements, including (i) the risk that the conditions to the Closing, including required regulatory approvals, are not satisfied or waived on a timely basis or at all, and the risk that the Mergers may not be completed on the anticipated terms, in the anticipated timeframe or at all, (ii) the occurrence of any event that could give rise to the termination of the Merger Agreement, (iii) the risks and costs associated with the Mergers and integrating OnRad and achieving the anticipated benefits of the Mergers, (iv) potential disruption to the businesses of the Company and OnRad, including the ability to retain and hire key personnel and to maintain relationships with customers, suppliers and other business partners, as well as diversion of management’s time and attention from ordinary course business operations to completion of the Mergers and integration matters, (v) potential litigation or regulatory action relating to the Mergers, (vi) the effect of the Mergers on the Company’s indebtedness and leverage, credit ratings and liquidity, (vii) legislative, regulatory and economic developments, including in the healthcare industry, (viii) the effect of the announcement, pendency or completion of the Mergers on the market price of the RadNet Common Stock, and (ix) the other risks described under “Risk Factors” in the Company’s most recent Annual Report on Form 10-K and subsequent Quarterly Reports on Form 10-Q. There may be additional risks, uncertainties and factors that we do not currently view as material or that are not necessarily known. Please read the Company’s filings with the SEC, which are available on the SEC’s website at https://www.sec.gov, for a discussion of risks and uncertainties that could cause actual results to differ from those in such forward-looking statements. You are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date of this Current Report on Form 8-K. All forward-looking statements in this Current Report on Form 8-K are qualified in their entirety by these cautionary statements. Except as required by law, the Company undertakes no obligation and does not intend to update or revise any forward-looking statements, whether as a result of new information, future results or otherwise.

No Offer or Solicitation

This communication is for informational purposes only and shall not constitute or form part of, an offer to sell or the solicitation of an offer to buy any securities, nor shall there be any sale of securities, in any jurisdiction in which such offer, solicitation, or sale would be unlawful prior to registration or qualification under the securities laws of any such jurisdiction.

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

ATTACHMENTS / EXHIBITS

AGREEMENT AND PLAN OF MERGER, DATED AS OF OCTOBER 26, 2026

FORM OF RESTRICTIVE COVENANT AND SUPPORT AGREEMENT, DATED OCTOBER 26, 2026

PRESS RELEASE DATED OCTOBER 26, 2026

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XBRL LABEL FILE

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