Business Combination Prospectus (Form 425)

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): May 14, 2026

GENTHERM INCORPORATED

(Exact name of registrant as specified in its charter)

Registrant's telephone number, including area code: (248) 348-9735

Former name or former address, if changed since last report: N/A

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. ☐

On May 14, 2026, the shareholders of Gentherm Incorporated (the "Company") approved an amendment (the "Amendment") to the Gentherm Incorporated 2023 Equity Incentive Plan (the "2023 Equity Plan"). The Amendment increases by 1,700,000 the maximum number of shares of common stock that may be issued pursuant to awards granted under the 2023 Equity Plan.

Prior to the Amendment, the 2023 Equity Plan provided for shares of common stock available for issuance (the "Share Limit") equal to the sum of (i) 3,730,000 shares, plus (ii) the number of shares of common stock subject to outstanding awards granted under the Gentherm Incorporated 2013 Equity Incentive Plan (the "2013 Equity Plan") (as of the effective date of the 2023 Equity Plan) that, after the effective date of the 2023 Equity Plan, are forfeited, surrendered, terminated (other than by exercise), cancelled, lapsed or reacquired by the Company prior to vesting, without the delivery of any shares of common stock, and otherwise comply with the recycling provisions of the 2013 Equity Plan and 2023 Equity Plan. The Amendment increases the Share Limit by 1,700,000 shares.

Except as amended by the Amendment, the other terms of the 2023 Equity Plan remain in full force and effect. A description of the terms of the 2023 Equity Plan is included in the Company's definitive proxy statement for the 2026 annual meeting of shareholders filed with the Securities and Exchange Commission on April 1, 2026 and as supplemented on April 10, 2026.

The Amendment is attached hereto as Exhibit 10.1 and is incorporated herein by reference.

At the annual meeting of shareholders of the Company on May 14, 2026 (the "Annual Meeting"), the Company's shareholders: elected nine directors, each to serve for a one-year term until the 2027 annual meeting of shareholders and until a successor has been duly elected and qualified, or until such director's earlier resignation, retirement or other termination of service; approved (on an advisory basis) the compensation of the Company's named executive officers; ratified the appointment of Ernst & Young LLP as the Company's independent registered public accounting firm for the year ending December 31, 2026; and approved the Amendment.

The final results of the voting are shown below.

Proposal No. 1 - Election of directors

Proposal No. 2 - Approval (on an advisory basis) of named executive officer compensation

Proposal No. 3 - Ratification of appointment of Ernst & Young LLP as independent registered public accounting firm for the year ending December 31, 2026

Proposal No. 4 - Approval of the Amendment to the Gentherm Incorporated 2023 Equity Incentive Plan

NO OFFER OR SOLICITATION

This Current Report on Form 8-K is not intended to and does not constitute an offer to sell or the solicitation of an offer to buy or exchange any securities or a solicitation of any vote or approval in any jurisdiction, nor shall there be any sale, issuance or transfer 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. It does not constitute a prospectus or prospectus equivalent document. No offering or sale of securities shall be made except by means of a prospectus meeting the requirements of Section 10 of the Securities Act of 1933, as amended (the "Securities Act"), and otherwise in accordance with applicable law.

Additional Information and Where to Find It

In connection with the proposed transaction among Gentherm, Modine Manufacturing Company ("Modine") and Modine's Performance Technologies business ("SpinCo") (the "Proposed Transaction"), the parties intend to file relevant materials with the SEC, including, among other filings, a registration statement on Form S-4 to be filed by Gentherm (the "Form S-4") that will include a preliminary proxy statement/prospectus of Gentherm and a definitive proxy statement/prospectus of Gentherm, the latter of which will be mailed to shareholders of Gentherm, and a registration statement on Form 10 to be filed by SpinCo that will incorporate by reference certain portions of the Form S-4 and will serve as an information statement/prospectus in connection with the spin-off of SpinCo from Modine. INVESTORS AND SECURITY HOLDERS OF GENTHERM AND MODINE ARE URGED TO READ THE PROXY STATEMENT/PROSPECTUS, THE INFORMATION STATEMENT/PROSPECTUS AND ANY OTHER DOCUMENTS THAT WILL BE FILED WITH THE SEC, AS WELL AS ANY AMENDMENTS OR SUPPLEMENTS TO THESE DOCUMENTS, CAREFULLY AND IN THEIR ENTIRETY WHEN THEY BECOME AVAILABLE BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION ABOUT GENTHERM, MODINE, SPINCO, THE PROPOSED TRANSACTION AND RELATED MATTERS. Investors and security holders will be able to obtain free copies of the Form S-4 and the proxy statement/prospectus (when available) and other documents filed with the SEC by Gentherm, Modine or SpinCo through the website maintained by the SEC at www.sec.gov. Copies of the documents filed with the SEC by Gentherm will be available free of charge on Gentherm's website at ir.Gentherm.com under the tab "Financial Info" and under the heading "SEC Filings." Copies of the documents filed with the SEC by Modine and SpinCo will be available free of charge on Modine's website at investors.Modine.com under the tab "Financials" and under the heading "SEC Filings."

Participants in the Solicitation

Gentherm and Modine and their respective directors and executive officers and other members of management and employees may be considered participants in the solicitation of proxies from Gentherm's shareholders in connection with the Proposed Transaction under the rules of the SEC. Information about the directors and executive officers of Gentherm is set forth its Annual Report on Form 10-K for the year ended December 31, 2025, which was filed with the SEC on February 19, 2026, and its proxy statement for its 2026 annual meeting of shareholders, which was filed with the SEC on April 1, 2026 and supplemented on April 10, 2026. To the extent holdings of Gentherm's securities by its directors or executive officers have changed since the amounts set forth in such filings, such changes have been or will be reflected on Initial Statements of Beneficial Ownership on Form 3 or Statements of Beneficial Ownership on Form 4 filed with the SEC. Information about the directors and executive officers of Gentherm and other information regarding the potential participants in the proxy solicitations and a description of their direct and indirect interests, by security holdings or otherwise, will be contained in the proxy statement/prospectus and other relevant materials to be filed with the SEC regarding the Proposed Transaction. Information about the directors and executive officers of Modine is set forth in its Annual Report on Form 10-K for the year ended March 31, 2025, which was filed with the SEC on May 21, 2025, and its proxy statement for its 2025 annual meeting of shareholders, which was filed with the SEC on July 9, 2025. To the extent holdings of Modine's securities by its directors or executive officers have changed since the amounts set forth in such filings, such changes have been or will be reflected on Initial Statements of Beneficial Ownership on Form 3 or Statements of Beneficial Ownership on Form 4 filed with the SEC. You may obtain these documents (when they become available) free of charge through the website maintained by the SEC at www.sec.gov and from Gentherm's website and Modine's website as described above.

Cautionary Statement Regarding Forward-Looking Statements

This Current Report on Form 8-K includes "forward-looking statements" as that term is defined in Section 27A of the Securities Act, and Section 21E of the Exchange Act, including statements regarding the Proposed Transaction among Gentherm, Modine and SpinCo. These forward-looking statements generally are identified by the words "believe," "feel," "project," "expect," "anticipate," "appear," "estimate," "forecast," "outlook," "target," "endeavor," "seek," "predict," "intend," "suggest," "strategy," "plan," "may," "could," "should," "will," "would," "will be," "will continue," "will likely result," or the negative thereof or variations thereon or similar terminology generally intended to identify forward-looking statements. All statements, other than historical facts, including, but not limited to, statements regarding the expected timing and structure of the Proposed Transaction, the ability of the parties to complete the Proposed Transaction, the expected benefits of the Proposed Transaction, including future financial and operating results, anticipated strategic benefits of the Proposed Transaction, the amount and timing of synergies from the Proposed Transaction, the tax consequences of the Proposed Transaction, the terms and scope of the expected financing in connection with the Proposed Transaction, the aggregate amount of indebtedness of the combined company following the closing of the Proposed Transaction, the combined company's plans, objectives, expectations and intentions, legal, economic and regulatory conditions, and any assumptions underlying any of the foregoing, are forward-looking statements.

These forward-looking statements are based on Gentherm's and Modine's current expectations and are subject to risks and uncertainties surrounding future expectations generally. Actual results could differ materially from those currently anticipated due to a number of risks and uncertainties, many of which are beyond Gentherm's and Modine's control. None of Gentherm, Modine, SpinCo or any of their respective directors, executive officers, advisors or representatives make any representation or provide any assurance or guarantee that the occurrence of the events expressed or implied in any forward-looking statements will actually occur, or if any of them do occur, what impact they will have on the business, results of operations or financial condition of Gentherm, Modine or the combined business. Should one or more of these risks or uncertainties materialize, or should underlying assumptions prove incorrect, actual results may vary materially from those indicated or anticipated by such forward-looking statements, including developments that could have a material adverse effect on Gentherm's and Modine's businesses and the ability to successfully complete the Proposed Transaction and realize its benefits. The inclusion of such statements should not be regarded as a representation that such plans, estimates or expectations will be achieved. Important factors that could cause actual results to differ materially from such plans, estimates or expectations include, among others, (1) that one or more closing conditions to the Proposed Transaction, including certain regulatory approvals, may not be satisfied or waived, on a timely basis or otherwise, including that a governmental entity may prohibit, delay or refuse to grant approval for the consummation of the Proposed Transaction, may require conditions, limitations or restrictions in connection with such approvals or that the required approval by the shareholders of Gentherm may not be obtained; (2) the risk that the Proposed Transaction may not be completed on the terms or in the time frame expected by Gentherm, Modine and SpinCo, or at all; (3) unexpected costs, charges or expenses resulting from the Proposed Transaction; (4) uncertainty of the expected financial performance of the combined company following completion of the Proposed Transaction; (5) failure to realize the anticipated benefits of the Proposed Transaction, including as a result of delay in completing the Proposed Transaction or integrating the businesses of Gentherm and SpinCo, on the expected timeframe or at all; (6) the ability of the combined company to implement its business strategy; (7) difficulties and delays in the combined company achieving revenue and cost synergies; (8) inability of the combined company to retain and hire key personnel; (9) the occurrence of any event that could give rise to termination of the Proposed Transaction; (10) the risk that shareholder litigation in connection with the Proposed Transaction or other litigation, settlements or investigations may affect the timing or occurrence of the Proposed Transaction or result in significant costs of defense, indemnification and liability; (11) evolving legal, regulatory and tax regimes; (12) changes in general economic and/or industry specific conditions or any volatility resulting from the imposition of and changing policies, including those policies with respect to tariffs; (13) actions by third parties, including government agencies; (14) the risk that the anticipated tax treatment of the Proposed Transaction is not obtained; (15) the risk of greater than expected difficulty in separating the business of SpinCo from the other businesses of Modine; (16) risks related to the disruption of management time from ongoing business operations due to the pendency of the Proposed Transaction, or other effects of the pendency of the Proposed Transaction on the relationship of any of the parties to the Proposed Transaction with their employees, customers, suppliers, or other counterparties; and (17) other risk

factors detailed from time to time in Gentherm's and Modine's reports filed with the SEC, including Gentherm's and Modine's annual reports on Form 10-K, quarterly reports on Form 10-Q, current reports on Form 8-K and other documents filed with the SEC, including documents that will be filed with the SEC in connection with the Proposed Transaction. The foregoing list of important factors is not exclusive.

Any forward-looking statements speak only as of the date of this Current Report on Form 8-K. None of Gentherm, Modine or SpinCo undertakes, and each party expressly disclaims, any obligation to update any forward-looking statements, whether as a result of new information or development, future events or otherwise, except as required by law. Readers are cautioned not to place undue reliance on any of these forward-looking statements.

SIGNATURES

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.

Date: May 19, 2026

Exhibit 10.1

First Amendment to

GENTHERM INCORPORATED

2023 EQUITY INCENTIVE PLAN

The Gentherm Incorporated 2023 Equity Incentive Plan (the "Plan") is amended by this First Amendment (this "First Amendment") in the following respects, effective from and after the date this First Amendment is approved by the shareholders of Gentherm Incorporated, in accordance with Section 21 of the Plan. Following such effective date, any reference to the "Plan" shall mean the Plan, as further amended by this First Amendment. All capitalized terms used but not otherwise defined herein shall have the respective meanings ascribed to such terms in the Plan.

1. Section 5(a) of the Plan is hereby deleted and replaced in its entirety with the following:

"Shares of Common Stock issued or to be issued under this Plan shall be authorized but unissued Common Stock. Subject to the other provisions of this Paragraph 5, the maximum number of shares of Common Stock which may be issued pursuant to Awards granted under this Plan or with respect to which Awards may be granted under this Plan shall not exceed in the aggregate (i) 5,430,000 shares of Common Stock plus (ii) the number of shares of Common Stock that, as of the Effective Date were subject to awards granted under the Prior Plan and that, on or after the Effective Date, expire or are forfeited, surrendered, terminated (other than by exercise), cancelled, lapsed or reacquired by the Corporation prior to vesting, without the delivery of any shares of Common Stock in accordance with the terms of such Prior Plan, and comply with the share recycling provisions of the Prior Plan and Paragraph 5(c) of this Plan (in each case, subject to adjustments as provided in this Paragraph 5) (the "Share Limit")."

2. This First Amendment shall be and is hereby incorporated into and forms a part of the Plan. Except as expressly provided herein, all terms and conditions of the Plan shall remain in full force and effect.