Results of Operations and Financial Condition. TriMas Corporation (the “Company”) issued a press release on July 30, 2026, reporting its financial results for the second quarter ending June 30, 2026. A copy of the press release is attached hereto as Exhibit 99.1 and is incorporated herein by reference. The press release is also available on the Corporation's website at www.trimas.com . The information presented in Exhibit 99.1 shall not be deemed “filed” for purposes of Section 18 of the Secu…

Results of Operations and Financial Condition. TriMas Corporation (the “Company”) issued a press release on April 30, 2026, reporting its financial results for the first quarter ending March 31, 2026. A copy of the press release is attached hereto as Exhibit 99.1 and is incorporated herein by reference. The press release is also available on the Corporation's website at www.trimas.com . The information presented in Exhibit 99.1 shall not be deemed “filed” for purposes of Section 18 of the Sec…

of Form 8-K. TriMas hereby undertakes to furnish on a supplemental basis a copy of any omitted schedule or exhibit to the Securities and Exchange Commission upon request. 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. TRIMAS CORPORATION Date: March 18, 2026 By: /s/ Jodi F. Robin Name: Jodi F. Robin Title: General Counsel and Secretary

Completion of Acquisition or Disposition of Assets As previously announced, on November 4, 2025, TriMas Company LLC, TriMas International Holdings LLC, Aero Products Group LLC and Rieke Germany GmbH & Co. KG, each of which are wholly owned subsidiaries of TriMas Corporation (“TriMas”), and TriMas (each a “Seller” and together, the “Sellers”) entered into an Equity Purchase Agreement (the “Purchase Agreement”) with Takeoff Buyer, Inc. (the “Purchaser”), an affiliate of Tinicum L.P. and funds m…

Named Executive Officer — Jill S. Stress: Jill S. Stress is departing from the Company effective March 27, 2026.

Director — Teresa M. Finley: Ms. Finley is retiring from the Board of Directors.

Results of Operations and Financial Condition. TriMas Corporation (the “Corporation”) issued a press release on February 26, 2026 , reporting its financial results for the fourth quarter and year ended December 31, 2025. A copy of the press release is attached hereto as an exhibit and is incorporated herein by reference. The press release is also available on the Corporation's website at www.trimas.com . The information furnished pursuant to this Item 2.02, including Exhibits 99.1 and 99.2, s…

CFO — Paul Swart: Paul Swart was appointed as the new CFO, succeeding Teresa M. Finley who has been serving as Interim CFO.

of Form 8-K. TriMas hereby undertakes to furnish on a supplemental basis a copy of any omitted schedule or exhibit to the Securities and Exchange Commission upon request. Forward-Looking Statements This Current Report on Form 8-K contains forward-looking statements within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934 about the Transaction. These forward-looking statements can be identified by the use of forward-looking words, s…

Results of Operations and Financial Condition. TriMas Corporation (the “Company”) issued a press release on October 28, 2025, reporting its financial results for the third quarter ending September 30, 2025. A copy of the press release is attached hereto as Exhibit 99.1 and is incorporated herein by reference. The press release is also available on the Corporation's website at www.trimas.com . The information presented in Exhibit 99.1 shall not be deemed “filed” for purposes of Section 18 of t…

Results of Operations and Financial Condition. TriMas Corporation (the “Company”) issued a press release on July 29, 2025, reporting its financial results for the second quarter ending June 30, 2025. A copy of the press release is attached hereto as Exhibit 99.1 and is incorporated herein by reference. The press release is also available on the Corporation's website at www.trimas.com . The information presented in Exhibit 99.1 shall not be deemed “filed” for purposes of Section 18 of the Secu…

President and Chief Executive Officer — Mr. Thomas Snyder: Thomas Snyder was appointed as the new President and CEO of TriMas Corporation, bringing extensive industry experience.

Results of Operations and Financial Condition. TriMas Corporation (the “Company”) issued a press release on April 29, 2025, reporting its financial results for the first quarter ending March 31, 2025. A copy of the press release is attached hereto as Exhibit 99.1 and is incorporated herein by reference. The press release is also available on the Corporation's website at www.trimas.com . The information presented in Exhibit 99.1 shall not be deemed “filed” for purposes of Section 18 of the Sec…

Entry into a Material Definitive Agreement. Amendment to Existing Credit Agreement On March 31, 2025, TriMas Corporation, a Delaware corporation (the “Company”), TriMas Company LLC, a Delaware limited liability company (the “Parent Borrower”), and certain other subsidiaries of the Company party thereto (the “Subsidiary Loan Parties”) entered into that certain Eighth Amendment (the “Amendment”), by and among the Company, the Parent Borrower, the Subsidiary Loan Parties, the lenders party there…

Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant. The information contained in and incorporated into

Chief Financial Officer — Scott A. Mell: Scott A. Mell resigned as Chief Financial Officer and employee of TriMas Corporation.

Results of Operations and Financial Condition. TriMas Corporation (the “Corporation”) issued a press release on February 27, 2025 , reporting its financial results for the fourth quarter and year ended December 31, 2024. A copy of the press release is attached hereto as an exhibit and is incorporated herein by reference. The press release is also available on the Corporation's website at www.trimas.com . The information furnished pursuant to this Item 2.02, including Exhibit 99.1, shall not b…

The company implemented an executive retention program to retain key officers during the transition of the CEO.

Class III director — Shawn Sedaghat: Appointment of Shawn Sedaghat as a Class III director and member of the Governance and Nominating Committee.

President and Chief Executive Officer (CEO) — Thomas Amato: Mr. Amato is transitioning from his role as President and CEO with a planned departure by June 30, 2025.

Results of Operations and Financial Condition. TriMas Corporation (the “Company”) issued a press release on November 4, 2024, reporting its financial results for the third quarter ending September 30, 2024. A copy of the press release is attached hereto as Exhibit 99.1 and is incorporated herein by reference. The press release is also available on the Corporation's website at www.trimascorp.com . The information presented in Exhibit 99.1 shall not be deemed “filed” for purposes of Section 18…

Results of Operations and Financial Condition. TriMas Corporation (the “Company”) issued a press release on July 30, 2024, reporting its financial results for the second quarter ending June 30, 2024. A copy of the press release is attached hereto as Exhibit 99.1 and is incorporated herein by reference. The press release is also available on the Corporation's website at www.trimascorp.com . The information presented in Exhibit 99.1 shall not be deemed “filed” for purposes of Section 18 of the…

Results of Operations and Financial Condition. TriMas Corporation (the “Company”) issued a press release on April 30, 2024, reporting its financial results for the first quarter ending March 31, 2024. A copy of the press release is attached hereto as Exhibit 99.1 and is incorporated herein by reference. The press release is also available on the Corporation's website at www.trimascorp.com . The information presented in Exhibit 99.1 shall not be deemed “filed” for purposes of Section 18 of the…

Chairman of the Board — Samuel Valenti III: Mr. Samuel Valenti III is retiring as Chairman of the Board and will not stand for reelection at the Annual Meeting.

Results of Operations and Financial Condition. TriMas Corporation (the “Corporation”) issued a press release on February 29, 2024 , reporting its financial results for the fourth quarter and year ended December 31, 2023. A copy of the press release is attached hereto as an exhibit and is incorporated herein by reference. The press release is also available on the Corporation's website at www.trimascorp.com . In addition, effective as of the first quarter of 2024, the Company will be modifying…