CAUTIONARY STATEMENT CONCERNING FORWARD-LOOKING STATEMENTS Unless the context otherwise indicates, all references in this Quarterly Report on Form 10-Q to “Orion,” “the Company,” “we,” “our,” or “us” are to Orion Group Holdings, Inc. and its subsidiaries as a whole. Certain information in this Quarterly Report on Form 10-Q, including but not limited to Management’s Discussion and Analysis of Financial Condition and Results of Operations (“MD&A”), may constitute forward-looking statements as such term is defined within the meaning of the “safe harbor” provisions of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. All statements other than statements of historical facts, including those that express a belief, expectation, or intention are forward-looking statements. The forward-looking statements may include projections and estimates concerning the timing and success of specific projects and our future production, our pipeline of opportunities, conversion of backlog, revenues, income and capital spending. Our forward-looking statements are generally accompanied by words such as “estimate,” “project,” “predict,” “believe,” “expect,” “anticipate,” “potential,” “plan,” “goal,” “may,” “will,” “could,” “would” or other words that convey the uncertainty of future events or outcomes. We have based these forward-looking statements on our current expectations and assumptions about future events. While our management considers these expectations and assumptions to be reasonable, they are inherently subject to significant business, economic, competitive, regulatory and other risks, contingencies and uncertainties, most of which are difficult to predict and many of which are beyond our control, including unforeseen productivity delays and other difficulties encountered in project execution, challenges incurred by virtue of our position as a substantial subcontractor that reports to a significantly larger project contractor, levels of government funding or other governmental budgetary constraints, contract modifications and changes, including change orders and contract cancellation at the discretion of the customer, and the general economic impact of government shutdowns, tariffs, trade wars and other geopolitical tensions. These and other important factors, including those described under “Risk Factors” in Part 1, Item 1A of our Annual Report on Form 10-K for the year ended December 31, 2025 (“2025 Form 10-K”) may cause our actual results, performance or achievements to differ materially from any future results, performance or achievements expressed or implied by these forward-looking statements. The forward-looking statements in this Quarterly Report on Form 10-Q speak only as of the date of this report; we disclaim any obligation to update these statements unless required by securities law, and we caution you not to rely on them unduly. MD&A provides a narrative analysis explaining the reasons for material changes in the Company’s (i) financial condition since the most recent fiscal year-end, and (ii) results of operations during the current fiscal year-to-date period and current fiscal quarter as compared to the corresponding periods of the preceding fiscal year. In order to better understand such changes, this MD&A should be read in conjunction with the Company’s audited consolidated financial statements and notes thereto included in our 2025 Form 10-K, Part II, Item 7 Management’s Discussion and Analysis of Financial Condition and Results of Operations included in our 2025 Form 10-K and with our unaudited condensed consolidated financial statements and related notes appearing elsewhere in this Quarterly Report on Form 10-Q. ​ 28 ​ Table of Contents Overview Orion Group Holdings, Inc. and its subsidiaries (hereafter collectively referred to as the “Company”), is a leading specialty construction company serving the infrastructure, industrial, and building sectors, providing services both on and off the water in the continental United States, Alaska, Hawaii, Canada and the Caribbean Basin through our marine segment and our concrete segment. Our marine segment provides construction, dredging and specialty services. Construction services include construction, restoration, maintenance, dredging and repair of marine transportation facilities, marine pipelines, bridges and causeways and marine environmental structures. Dredging services generally enhance or preserve the navigability of waterways or the protection of shorelines through the removal or replenishment of soil, sand or rock. Specialty services include design, salvage, demolition, surveying, towing, diving and underwater inspection, excavation and repair. We also perform engineering design, analysis, and consulting projects for both internal and external clients. Our concrete segment provides turnkey concrete construction services, including concrete surface place and finish, site preparation, layout, forming, and rebar placement for large commercial, structural and other associated business areas. ​ Our contracts are obtained primarily through competitive bidding in response to “requests for proposals” by federal, state and local agencies and through negotiation and competitive bidding with private parties and general contractors. Our bidding activity and strategies are affected by factors such as our backlog, current utilization of equipment and other resources, job location, our ability to obtain necessary surety bonds and competitive considerations. The timing and location of awarded contracts may result in unpredictable fluctuations in the results of our operations. ​ Most of our revenue is derived from fixed-price contracts. We record revenue on construction contracts over time, measured by the percentage of actual contract costs incurred to date to total estimated costs for each contract. There are a number of factors that can create variability in contract performance and therefore impact the results of our operations. The most significant of these include the following: ​ ● completeness and accuracy of the original bid; ● increases in commodity prices such as concrete, steel and fuel; ● customer delays, work stoppages, and other costs due to weather and environmental restrictions; ● subcontractor performance; ● unforeseen site conditions; ● availability and skill level of workers; and ● a change in availability and proximity of equipment and materials. All of these factors can have a negative impact on our contract performance, which can adversely affect the timing of revenue recognition and ultimate contract profitability. We plan our operations and bidding activity with these factors in mind and they generally have not had a material adverse impact on the results of our operations in the past. ​ 29 ​ Table of Contents Recent Developments JEM Acquisition On February 3, 2026, we entered into a Securities Purchase Agreement (the “Purchase Agreement”) and completed an acquisition (the “JEM 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, “JEM”). The purchase price consisted of: (a) $44.9 million in cash, subject to adjustments pursuant to the Purchase Agreement; a $12.0 million unsecured subordinated promissory note issued to the sellers; and 182,392 shares of Orion’s common stock, and (b) contingent post-closing cash payments dependent upon project profit realized from contracts of JEM under backlog identified in the Purchase Agreement. The cash consideration and related expenses were funded with cash on hand and borrowings of approximately $46.9 million under the UMB Credit Agreement (as defined below). JEM is engaged in the business of providing dredging, jetty and breakwater construction, environmental restoration and rehabilitation, and dam and spillway construction. UMB Credit Agreement On December 23, 2025, we entered into a five-year $120.0 million Credit Agreement (as amended, the “UMB 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 UMB 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. Consolidated Results of Operations Backlog Information Our contract backlog represents our estimate of the revenues we expect to realize under the portion of contracts remaining to be performed. Given the typical duration of our contracts, which is generally less than a year, our backlog at any point in time usually represents only a portion of the revenue that we expect to realize during a twelve-month period. We have not been adversely affected by contract cancellations or modifications in the past, however we may be in the future, especially in periods of economic uncertainty. Backlog as of the periods ended below were as follows (in millions): ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, 2026 ​ ​ ​ December 31, 2025 Marine segment ​ $ 554 ​ $ 480 Concrete segment ​ 168 ​ 160 Consolidated ​ $ 722 ​ $ 640 ​ Backlog is not necessarily indicative of future results. In addition to our backlog under contract, we also have a substantial number of projects in negotiation or pending award at any given time. 30 ​ Table of Contents Income Statement Comparisons Three months ended June 30, 2026 compared with three months ended June 30, 2025 ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended June 30, ​ ​ ​ ​ 2026 2025 ​ ​ ​ ​ Amount ​ ​ ​ Amount ​ ​ (dollar amounts in thousands) Contract revenues ​ $ 221,878 $ 205,286 Cost of contract revenues ​ 198,951 179,489 Gross profit ​ 22,927 25,797 Selling, general and administrative expenses ​ 24,395 22,774 Gain on disposal of assets, net ​ ​ (153) ​ ​ (409) Operating (loss) income ​ (1,315) 3,432 Other (expense) income: ​ ​ ​ Interest expense ​ (2,505) (2,920) Other income ​ 149 117 Other expense, net ​ (2,356) (2,803) (Loss) income before income taxes ​ (3,671) 629 Income tax expense (benefit) ​ 474 (212) Net (loss) income ​ $ (4,145) $ 841 ​ Contract Revenues. Contract revenues for the three months ended June 30, 2026 of $221.9 million increased $16.6 million, or 8%, as compared to $205.3 million in the prior year period. The increase was driven by the concrete segment, reflecting strong demand, new project awards and higher volumes. This increase was partially offset by a reduction in marine revenue, primarily attributable to the timing of project start-ups due to client-related issues such as site readiness and timing of delivery of client-provided materials. Gross Profit. Gross profit was $22.9 million for the three months ended June 30, 2026 compared to $25.8 million in the prior year period, a decrease of $2.9 million, or 11%. The decrease was primarily driven by lower marine volume and equipment utilization. The decrease was partially offset by favorable project execution within the concrete segment. ​ Selling, General and Administrative Expenses. Selling, general and administrative (“SG&A”) expenses were $24.4 million for the three months ended June 30, 2026 compared to $22.8 million in the prior year period, an increase of $1.6 million or 7%. The increase in SG&A was primarily attributable to costs to support business growth. ​ Gain on Disposal of Assets, net. During the three months ended June 30, 2026 and 2025, we realized net gains on disposal of assets of $0.2 million and $0.4 million, respectively. ​ Other Expense, net. Other expense primarily reflects interest on our borrowings, partially offset by interest income. ​ Income Tax Expense (Benefit). We recorded tax expense of $0.5 million in the three months ended June 30, 2026, compared to a tax benefit of $0.2 million in the prior year period. ​ 31 ​ Table of Contents Six months ended June 30, 2026 compared with six months ended June 30, 2025 ​ ​ ​ ​ ​ ​ ​ ​ ​ Six Months Ended June 30, ​ ​ ​ ​ 2026 2025 ​ ​ ​ ​ Amount ​ ​ ​ Amount ​ ​ (dollar amounts in thousands) Contract revenues ​ $ 438,179 $ 393,939 Cost of contract revenues ​ 389,373 345,127 Gross profit ​ 48,806 48,812 Selling, general and administrative expenses ​ 51,104 45,319 Gain on disposal of assets, net ​ ​ (188) ​ ​ (772) Operating (loss) income ​ (2,110) 4,265 Other (expense) income: ​ ​ ​ Interest expense ​ (4,036) (5,254) Other income ​ 310 344 Other expense, net ​ (3,726) (4,910) Loss before income taxes ​ (5,836) (645) Income tax benefit ​ (6,378) (72) Net income (loss) ​ $ 542 $ (573) ​ Contract Revenues. Contract revenues for the six months ended June 30, 2026 of $438.2 million increased $44.3 million, or 11%, as compared to $393.9 million in the prior year period. The increase was primarily due to the concrete segment, reflecting strong demand, new project awards, and higher volumes. This increase was partially offset by a reduction in marine revenue, primarily attributable to the timing of project start-ups. Gross Profit. Gross profit was $48.8 million for both the six months ended June 30, 2026 and in the prior year period. While revenues increased during the same periods, revenue mix and lower equipment utilization in our marine segment caused gross profit to remain flat. ​ Selling, General and Administrative Expenses. SG&A expenses were $51.1 million for the six months ended June 30, 2026 compared to $45.3 million in the prior year period, an increase of $5.8 million or 13%. The increase in SG&A was due to costs associated with the JEM Acquisition and other costs to support business growth. ​ Gain on Disposal of Assets, net. During the six months ended June 30, 2026 and 2025, we realized net gains on disposal of assets of $0.2 million and $0.8 million, respectively. ​ Other Expense, net. Other expense primarily reflects interest on our borrowings, partially offset by interest income. ​ Income Tax Benefit. We recorded a tax benefit of $6.4 million in the six months ended June 30, 2026, compared to $0.1 million in the prior year period. The tax benefit for the six months ended June 30, 2026 primarily relates to a decrease in the valuation allowance attributable to the recognition of the deferred tax liabilities arising from the fair value adjustments recorded as part of the JEM Acquisition. These deferred tax liabilities represent a source of future taxable income that supports the realizability of the Company’s deferred tax assets. 32 ​ Table of Contents Segment Results The following table sets forth, for the periods indicated, statements of operations data by segment, segment revenues as a percentage of consolidated revenues and segment operating income (loss) as a percentage of segment revenues. Three months ended June 30, 2026 compared with three months ended June 30, 2025 ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended June 30, ​ ​ 2026 ​ 2025 ​ ​ ​ ​ Amount ​ Amount ​ ​ (dollar amounts in thousands) Contract revenues ​ ​ ​ ​ ​ ​ Marine segment ​ $ 130,842 ​ $ 135,302 Concrete segment ​ 91,036 ​ 69,984 Total ​ $ 221,878 ​ $ 205,286 ​ ​ ​ ​ ​ ​ ​ Operating income (loss) ​ ​ ​ ​ Marine segment ​ $ 7,701 ​ $ 13,661 Concrete segment ​ 4,199 ​ 2,593 Total ​ $ 11,900 ​ $ 16,254 ​ ​ ​ ​ ​ ​ ​ General corporate ​ $ (13,215) ​ $ (12,822) Consolidated ​ $ (1,315) ​ $ 3,432 ​ Marine Segment Revenues for our marine segment for the three months ended June 30, 2026 were $130.8 million compared to $135.3 million for the three months ended June 30, 2025. Operating income for our marine segment for the three months ended June 30, 2026 was $7.7 million, compared to $13.7 million for the three months ended June 30, 2025. Marine revenue and operating income were down primarily due to the delays of project start-ups and lower equipment utilization. Concrete Segment Revenues for our concrete segment for the three months ended June 30, 2026 were $91.0 million compared to $70.0 million for the three months ended June 30, 2025. Operating income for our concrete segment for the three months ended June 30, 2026 was $4.2 million, compared to operating income of $2.6 million for the three months ended June 30, 2025. The increases were primarily driven by robust demand, an expansion into site civil services and strong project execution. 33 ​ Table of Contents Six months ended June 30, 2026 compared with six months ended June 30, 2025 ​ ​ ​ ​ ​ ​ ​ ​ ​ Six Months Ended June 30, ​ ​ 2026 ​ 2025 ​ ​ ​ ​ Amount ​ Amount ​ ​ (dollar amounts in thousands) Contract revenues ​ ​ ​ ​ ​ ​ Marine segment ​ $ 240,971 ​ $ 262,465 Concrete segment ​ 197,208 ​ 131,474 Total ​ $ 438,179 ​ $ 393,939 ​ ​ ​ ​ ​ ​ ​ Operating income (loss) ​ ​ ​ ​ Marine segment ​ $ 14,281 ​ $ 25,983 Concrete segment ​ 11,935 ​ 4,402 Total ​ $ 26,216 ​ $ 30,385 ​ ​ ​ ​ ​ ​ ​ General corporate ​ $ (28,326) ​ $ (26,120) Consolidated ​ $ (2,110) ​ $ 4,265 ​ Marine Segment Revenues for our marine segment for the six months ended June 30, 2026 were $241.0 million compared to $262.5 million for the six months ended June 30, 2025. Operating income for our marine segment for the six months ended June 30, 2026 was $14.3 million, compared to $26.0 million for the six months ended June 30, 2025. Marine revenue and operating income were down primarily due to delays in project start-ups and lower equipment utilization. Concrete Segment ​ Revenues for our concrete segment for the six months ended June 30, 2026 were $197.2 million compared to $131.5 million for the six months ended June 30, 2025. Operating income for our concrete segment for the six months ended June 30, 2026 was $11.9 million, compared to operating income of $4.4 million for the six months ended June 30, 2025. The increases were primarily driven by robust demand, an expansion into site civil services and strong project execution. ​ Liquidity and Capital Resources ​ Changes in working capital are normal within our business given the varying mix in size, scope, seasonality and timing of delivery of our projects. At June 30, 2026, our working capital was $92.0 million, as compared to $74.3 million at December 31, 2025. As of June 30, 2026, we had unrestricted cash on hand of $2.5 million. Our borrowing availability under the revolving portion of our UMB Credit Agreement at June 30, 2026 was approximately $22.6 million. Our primary liquidity needs are to finance our working capital and fund capital expenditures. Historically, our sources of liquidity have been cash provided by our operating activities, sale of underutilized assets, borrowings under our credit facilities, and equity issuances. The assessment of our liquidity requires us to make estimates of future activity and judgments about whether we are compliant with financial covenant calculations under our debt and other agreements and have adequate liquidity to operate. Significant assumptions used in our forecasted model of liquidity include forecasted sales, costs, and capital expenditures, as well as expected 34 ​ Table of Contents timing and proceeds of planned asset sale transactions. As of June 30, 2026, management believes the Company will have adequate liquidity for its operations for at least the next 12 months. ​ Cash Flow ​ The following table provides information regarding our cash flows and our capital expenditures for the six months ended June 30, 2026 and 2025 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ Six Months Ended ​ ​ June 30, ​ ​ ​ ​ 2026 ​ ​ ​ 2025 Net income (loss) ​ $ 542 ​ $ (573) Adjustments to remove non-cash and non-operating items ​ ​ 14,057 ​ ​ 18,510 Cash flow from net income (loss) after adjusting for non-cash and non-operating items ​ ​ 14,599 ​ ​ 17,937 Change in operating assets and liabilities (working capital) ​ ​ (27,298) ​ ​ (26,942) Cash flows used in operating activities ​ $ (12,699) ​ $ (9,005) Cash flows used in investing activities ​ $ (62,296) ​ $ (14,976) Cash flows provided by (used in) financing activities ​ $ 75,934 ​ $ (2,603) ​ ​ ​ ​ ​ ​ ​ Capital expenditures (included in investing activities above) ​ $ (20,108) ​ $ (16,165) ​ Operating Activities. During the six months ended June 30, 2026, we used approximately $12.7 million of cash in our operating activities. The net cash outflow was comprised of $14.6 million of cash inflows from net income, after adjusting for non-cash and non-operating items, offset by $27.3 million of outflows related to changes in net working capital. The changes in net working capital, which are reflected as changes in operating assets and liabilities in our Condensed Consolidated Statements of Cash Flows, were primarily driven by a $56.6 million outflow pursuant to the relative timing and significance of project progression and billings during the period and a $3.1 million decrease in operating lease liabilities and $0.8 million of other outflows, partially offset by a $30.7 million cash inflow related to a decrease in our net positions of accounts receivable, accounts payable, and accrued liabilities during the period and a $2.5 million decrease in prepaid expenses. Investing Activities. During the six months ended June 30, 2026, we used approximately $62.3 million of cash in our investing activities. Cash used in investing activities relating to the JEM Acquisition totaled $42.9 million in the six months ended June 30, 2026. Capital asset additions and betterments to our fleet were $20.1 million and $16.2 million in the six months ended June 30, 2026 and 2025, respectively. Financing Activities. During the six months ended June 30, 2026, we were provided approximately $75.9 million of cash by our financing activities. During the six months ended June 30, 2026, we had net borrowings of $36.0 million on the UMB revolving credit line, borrowings of $40.0 million related to the JEM Acquisition and borrowings of $2.0 million related to the UMB equipment line of credit. ​ 35 ​ Table of Contents Effect of Inflation We are subject to the effects of inflation through increases in the cost of raw materials and other items such as fuel, concrete and steel. Due to the relative short-term duration of our projects, we are generally able to include anticipated cost increases in the pricing of our bids. Critical Accounting Estimates Refer to our 2025 Form 10-K for a description of our critical accounting estimates that require us to make estimates and assumptions that affect both the Company’s carrying values of its assets and liabilities, and the reported amounts of revenues and expenses during the reporting period. There have been no material changes or developments during the reporting period with respect to methodologies that we used when developing critical accounting estimates as disclosed in our 2025 Form 10-K.