to the Company’s Current Report on Form 8-K, including Exhibit 99.1 attached hereto, is being furnished and shall not be deemed “filed” for any purpose, and shall not be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended (the “Securities Act”), or the Securities Exchange Act of 1934, as amended (the “Exchange Act”), except as expressly set forth by specific reference in such filing. ​ Use of Non-GAAP Financial Information To help understand the Company…

The filing describes an amendment to the company's long-term incentive plan, which is not a management change event.

to the Company’s Current Report on Form 8-K, including Exhibit 99.1 attached hereto, is being furnished and shall not be deemed “filed” for any purpose, and shall not be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended (the “Securities Act”), or the Securities Exchange Act of 1934, as amended (the “Exchange Act”), except as expressly set forth by specific reference in such filing. ​ Use of Non-GAAP Financial Information To help understand the Company…

Director — Thomas N. Amonett, Peggy M. Foran: Directors are retiring from the Board and all committee positions effective upon the closing of Orion's 2026 Annual Meeting of Stockholders.

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers. On March 16, 2026, each of Thomas N. Amonett and Peggy M. Foran informed the Board of Directors (the “Board”) of Orion Group Holdings, Inc. (“Orion”) that they would retire from the Board and all committee positions effective upon the closing of Orion’s 2026 Annual Meeting of Stockholders scheduled to be held on May 19, 2026. Mr. Amonett’s and Ms.…

to the Company’s Current Report on Form 8-K, including Exhibit 99.1 attached hereto, is being furnished and shall not be deemed “filed” for any purpose, and shall not be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended (the “Securities Act”), or the Securities Exchange Act of 1934, as amended (the “Exchange Act”), except as expressly set forth by specific reference in such filing. ​ Use of Non-GAAP Financial Information To help understand the Company…

Completion of Acquisition or Disposition of Assets. The information set forth under

Entry into a Material Definitive Agreement. On February 3, 2026, Orion Group Holdings, Inc. (“Orion”) entered into a Securities Purchase Agreement (the “Purchase Agreement”) and completed an acquisition (the “Acquisition”) of all of the capital stock of J.E. McAmis, Inc., a California corporation, and all of the membership interests in JEM Marine Leasing, LLC, a Washington limited liability company (collectively, the “Acquired Companies” and each an “Acquired Company”). The Acquired Companies…

of Form 8-K and shall not be deemed to be “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”) or otherwise subject to the liabilities of that section, nor shall such information 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 a filing. Cautionary Statement Regarding Forward-Looking Statements The matters discussed in this Report…

Unregistered Sales of Equity Securities. The information set forth under

Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant. The information set forth under

are qualified in their entirety by the full text of the Credit Agreement, which is filed as Exhibit 10.1 hereto and incorporated herein by reference. ​

Entry into a Material Definitive Agreement. On December 23, 2025, Orion Group Holdings, Inc., as borrower (the “Company”) entered into a $120.0 million Credit Agreement (the “Credit Agreement”) with certain financial institutions from time-to-time party thereto, as lenders, and UMB Bank, N.A., as Administrative Agent and Issuing Bank (the “Agent”). The Credit Agreement consists of a $60.0 million revolving loan, a $20.0 million equipment term loan, and a $40.0 million acquisition term loan. A…

are qualified in their entirety by the full text of the Credit Agreement, which is filed as Exhibit 10.1 hereto and incorporated herein by reference. ​

Termination of a Material Definitive Agreement. On December 23, 2025, in connection with entering into the Credit Agreement, the Company’s prior Credit Agreement, dated May 15, 2023, with White Oak ABL, LLC and White Oak Commercial Finance, LLC (the “Prior Credit Agreement) was terminated, and all amounts outstanding thereunder were repaid. In connection with the termination, the Company paid a make whole payment of approximately $1.1 million.

Director with committee assignments — Robert Ledford: Robert Ledford was appointed to serve on the Compensation Committee and Audit Committee of the Board of Directors.

to the Company’s Current Report on Form 8-K, including Exhibit 99.1 attached hereto, is being furnished and shall not be deemed “filed” for any purpose, and shall not be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended (the “Securities Act”), or the Securities Exchange Act of 1934, as amended (the “Exchange Act”), except as expressly set forth by specific reference in such filing. ​ Use of Non-GAAP Financial Information To help understand the Company…

Results of Operations and Financial Condition. On October 29, 2025, Orion Group Holdings, Inc. (the “Company”) held an earnings call to discuss its financial results for the third quarter ended September 30, 2025. Due to technical issues, the beginning of the earnings call may not have been accessible to all participants. Accordingly, the Company is furnishing as Exhibit 99.1 to this Current Report on Form 8-K a full transcript of the earnings call.

Director — Mr. Robert Ledford: Appointment of Mr. Robert Ledford as a new director to the Board.

to the Company’s Current Report on Form 8-K, including Exhibit 99.1 attached hereto, is being furnished and shall not be deemed “filed” for any purpose, and shall not be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended (the “Securities Act”), or the Securities Exchange Act of 1934, as amended (the “Exchange Act”), except as expressly set forth by specific reference in such filing. ​ Use of Non-GAAP Financial Information To help understand the Company…

Executive Vice President, Chief Financial Officer and Treasurer — Scott Thanisch: Mr. Scott Thanisch ceased serving as the Executive Vice President, Chief Financial Officer and Treasurer with severance benefits.

Executive Vice President, Chief Financial Officer and Treasurer — Scott Thanisch: Mr. Thanisch is departing, and Alison Vasquez has been appointed as the new CFO.

to the Company’s Current Report on Form 8-K, including Exhibit 99.1 attached hereto, is being furnished and shall not be deemed “filed” for any purpose, and shall not be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Securities Exchange Act of 1934, as amended, except as expressly set forth by specific reference in such filing. ​ Use of Non-GAAP Financial Information To help understand the Company’s financial performance, the Company has su…

to the Company’s Current Report on Form 8-K, including Exhibit 99.1 attached hereto, is being furnished and shall not be deemed “filed” for any purpose, and shall not be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Securities Exchange Act of 1934, as amended, except as expressly set forth by specific reference in such filing. ​ Use of Non-GAAP Financial Information To help understand the Company’s financial performance, the Company has su…

to the Company’s Current Report on Form 8-K, including Exhibit 99.1 attached hereto, is being furnished and shall not be deemed “filed” for any purpose, and shall not be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Securities Exchange Act of 1934, as amended, except as expressly set forth by specific reference in such filing. ​ Use of Non-GAAP Financial Information To help understand the Company’s financial performance, the Company has su…