#1ORION Investor Presentation February 2024#2Disclaimer ORION This presentation contains, and the officers and directors of the Company may from time to time make, statements that are considered forward looking statements within the meaning of the Securities Act of 1933 and the Securities Exchange Act of 1934. These forward-looking statements are subject to a number of risks and uncertainties, many of which are beyond our control, which may include statements about: our business strategy; our financial strategy; our industry outlook; and our expected margin growth; and our plans, objectives, expectations, forecasts, outlook and intentions. All of these types of statements, other than statements of historical fact included in this presentation, are forward-looking statements. In some cases, forward-looking statements can be identified by terminology such as "may," "will," "could," "should," "expect," "plan," "project," "intend," "anticipate," "believe," "estimate,” “predict," "potential," "pursue," "target," "continue," the negative of such terms or other comparable terminology. The forward-looking statements contained in this presentation are largely based on our expectations, which reflect estimates and assumptions made by our management. These estimates and assumptions reflect our best judgment based on currently known market conditions and other factors. Although we believe such estimates and assumptions to be reasonable, they are inherently uncertain and involve a number of risks and uncertainties that are beyond our control. In addition, management's assumptions about future events may prove to be inaccurate. Management cautions all readers that the forward-looking statements contained in this presentation are not guarantees of future performance, and we cannot assure any reader that such statements will be realized or the forward-looking events and circumstances will occur. Actual results may differ materially from those anticipated or implied in the forward-looking statements due to factors listed in the "Risk Factors" section in our filings with the U.S. Securities and Exchange Commission and elsewhere in those filings. Additional factors or risks that we currently deem immaterial, that are not presently known to us or that arise in the future could also cause our actual results to differ materially from our expected results. Given these uncertainties, investors are cautioned that many of the assumptions upon which our forward-looking statements are based are likely to change after the date the forward-looking statements are made. The forward-looking statements speak only as of the date made, and we undertake no obligation to publicly update or revise any forward-looking statements for any reason, whether as a result of new information, future events or developments, changed circumstances, or otherwise, notwithstanding any changes in our assumptions, changes in business plans, actual experience or other changes. These cautionary statements qualify all forward-looking statements attributable to us or persons acting on our behalf. This presentation may contain the financial measures: adjusted net income, EBITDA, adjusted EBITDA, and adjusted EPS, which are not calculated in accordance with U.S. GAAP. If presented, a reconciliation of the non-GAAP financial measures to the most directly comparable GAAP financial measure will be provided in the Appendix to this presentation. 2#3Orion at a Glance ORION Orion is a leading specialty construction company in the U.S., Canada and Caribbean Basin Services Company Overview . • Marine: Transportation facility & infrastructure construction; dredging • Concrete: Commercial, structural, and industrial Regions Served Headquarters Hawaii Geographic Footprint Key Statistics $711.8mm $23.8mm 2023 Revenue 1994 Founded 2023 Adj. EBITDA ORN (NYSE) Ticker ~2,400 Houston, TX Headquarters Employees Backlog Ended 12/31/23 $160M Concrete 21% $762M 79% $602M Marine Marine Concrete Caribbean Basin 3#4Three Takeaways 1 2 ORION 3 EXPERIENCED NEW MANAGEMENT TEAM FOCUSED ON IMPROVING FINANCIAL PERFORMANCE CEO and CFO bring wealth of industry knowledge, operational experience, leadership and strong relationships in the public sector VITAL PROVIDER OF MARINE AND CONCRETE SERVICES TO CRITICAL INFRASTRUCTURE AND COMMERCIAL PROJECTS Operating in growing markets-Marine driven by government spending and Concrete driven by robust Texas market SIGNIFICANT UPSIDE POTENTIAL Changes made in the last year have laid the foundation for accelerated, profitable growth and improved shareholder returns 4#5Compelling Investment Opportunity 6 5 Significant Upside Potential: Strong demand in both concrete and marine segments 1 Mission Critical Specialty Construction Provider with Sustainable Competitive Advantages 2 ORION Experienced New Management Team Focused on Improved Financial Performance ORION 3 Large Market Opportunity with Strong Tailwinds and Demand Drivers 3-Point Strategic Plan To Deliver Enhanced Growth and Returns 4 Diversified Revenue with Industry Leaders and Government Clients LO 5#61 Mission Critical Specialty Construction Provider with Sustainable Advantages ORION Market Credibility ► Trusted provider with decades of operating experience ► Long-term, embedded relationships ► Diverse customer base - - Federal, State, Municipal Governments (44% of 2023 Revenue) Private commercial and industrial clients (66% of 2023 Revenue) Market Leader ► Leading specialty concrete constructor in attractive Texas market Well-positioned to take advantage of $17bn Infrastructure Bill funding to ports, waterways and broader infrastructure developments ▸ Robust backlog of $762 mm with industry leaders and government customers Critical Service Provider ►Leading specialty construction services provider operating in the continental U.S., Hawaii, Alaska, Canada and the Caribbean Basin Broad range of marine construction including marine transportation, facility construction and dredging and diving services ►Leading Jones Act dredger focused in the Gulf Coast Concrete construction services including commercial, structural and industrial services High-Barriers to Entry ▸ Jones Act prohibits foreign competition from dredging in the U.S. market ► Marine specialty equipment is very expensive and requires significant upfront investment to enter market - Orion owns ~900 specialty pieces of equipment High stakes involved in complex concrete projects ང་ H ORION CO 6#72 Deep and Talented Management Team Focused on Operational Transformation Travis Boone, PE Chief Executive Officer Scott Thanisch Chief Financial Officer ORION 30 Years of Industry Experience Leadership and management experience across the civil, utility / pipeline and commercial building construction industries • Formerly Regional Chief Executive of AECOM, leading a large multidisciplinary business since May 2017 Previously held other key leadership positions since 1999 with AECOM/URS. Several companies in the utility / pipeline construction and commercial building construction industries prior to that. • • 28 Years of Industry Experience Multi-disciplinary finance experience, including corporate development, FP&A, treasury, strategy and accounting across numerous industries Formerly Chief Financial Officer of a commercial construction services company and a $1 billion global aviation services company Experienced in corporate transformations, financial transactions, and digitization and process improvement • • • Scott Cromack Executive Vice President Orion Marine Group 30 Years of Industry Experience Recently served as a Senior Vice President at Texas Sterling Construction Held a number of construction and project management positions over his career with companies including Kiewit and Zachry Construction Executive experience in company restructuring, negotiation and resolution as well as division level management with profit and loss responsibilities Ardell Allred Executive Vice President TAS 30 Years of Industry Experience Held a number of construction and project management positions over his career with companies including Kiewit and Zachry Construction SVP of Operations since 2019 Implemented cost savings strategies and project forecasting / controls improvements Led equipment rationalization and marine fleet right-sizing 7#83 Large Market Opportunity with Strong Tailwinds and Demand Drivers ORION Favorable drivers across business segments include the Infrastructure & Jobs Act, with a regional focus in rapidly growing regions and other key developments Orion's Core Markets (1) Marine Market Vertical Construction Market ~$11 billion Addressable market ~$20 billion Addressable market ROA Marine Growth Drivers U.S. Navy expansion in the Pacific Port expansion and maintenance (as a result of Panama Canal expansion) Bridges and dredging (aging infrastructure and reoccurring maintenance) Downstream energy (LNG and renewables) Coastal rehabilitation (increased disaster recovery from regional weather events, environmental remediation and sea level rise) Concrete Growth Drivers Rapidly growing Texas market (strong population growth) Distribution center expansion in Texas Economic growth and expansion (leading job growth rates in Texas) Industrial developments (trends of on-shoring and manufacturing growth) Civil and public construction (aging infrastructure and reoccurring maintenance) Additional upside from the federal infrastructure bill, which is not included in current market growth estimates, is expected to significantly boost spending in Orion's core markets $1.2 trillion Infrastructure Investment and Jobs Act Source: IBIS. (1) Marine market is inclusive of: U.S. Marine Construction, Conservation & Development Construction, Harbor & Port Facilities and Port Expansion, Maintenance and Dredging markets. Concrete market is inclusive of: TX Commercial Building Construction and Industrial Building Construction markets. 8#9Marine Segment Overview ORION Orion Marine benefits from high-margin projects with high barriers of entry and consistent maintenance demand • Overview Services the infrastructure sector to carry out construction, Maintenance dredging provides a recurring source of design and specialty services for marine structures revenue due to natural sedimentation in the nation's shipping channels and ports All of Orion's dredges are Jones Act vessels, preventing foreign competition from dredging in the U.S. market • Construction Services include construction, restoration, maintenance & repair of ports and docks, marine pipelines, marine transportation facilities, bridges and 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 (1) Calculated over most recent 5-year period. (2) As of December 31, 2022. Marine Revenue & Adj EBITDA Margin $369.1 $388.2 ($ in millions) $395.9 $339.2 $263.9 12.3% 10.4% 9.3% 8.1% 5.2% 2019 2020 2021 2022 2023 Marine Revenue Adj EBITDA Margin Marine Revenue Backlog $340.7 $202.6 $376.9 ($ in millions) $216.7 $602.5 2019 2020 2021 2022 2023 9#10Concrete Segment Overview Improved project margin focus has laid the groundwork for future success • • . • Overview Provides turnkey concrete construction services including place and finish, site work, layout, forming, rebar Focusing on Dallas and Houston market; exiting low-margin Central Texas market New bidding strategy to focus on quality projects at strong margins Upgrading project management systems to drive higher project visibility and standards Light Commercial Services include horizontally poured concrete for large tilt walls, slabs, foundations, paving, and sidewalks · Structural Services include elevated concrete pouring for products such as columns, decking, elevated beams and structural walls up to 45 stories (1) Calculated over most recent 5-year period. (2) As of December 31, 2022. ORION Concrete Revenue & Adj EBITDA Margin ($ in millions) $409.1 $339.3 $321.8 $337.4 $315.9 2.1% 0.3% 1.0% -1.2% -2.1% 2019 2020 2021 2022 2023 Adj EBITDA Margin Concrete Revenue Concrete Revenue Backlog $231.6 $236.9 $232.1 $213.1 ($ in millions) $159.7 2019 2020 2021 2022 2023 10#114 Diversified Revenue with Industry Leaders ORION Long-tenured relationships with blue-chip clients across federal, state, local and private customers in both the marine and concrete segments PORT NOLA THE PORT OF NEW ORLEANS High Quality Customer Base Marine BOSTCO Carnival ConocoPhillips STORAGE & TERMINAL SERVICES Port of Seattle Oiltanking FÖRT Texas Department TAMPA PORT AUTHORITY of Transportation CANAVERAL US Army Corps of Engineers® 46% ■ Private COAST ARTMENT DEPARTA 3 OF THE NAVE OF AMERI ED SIMIES OF NORTH CAROLINA OF HOUST AUTHO PHA PORT OF CHOUSTON TEXAS STATE OF PARTMENT OF TRANSPORTA USDA FDOT 26% Revenue by Customer Type(1) 38% Concrete CHOATE -CONSTRUCTION - EEREED Gilbane ARCH-CON CONSTRUCTION, L. P. H Hoar Construction alston CONSTRUCTION BURTON CONSTRUCTION CORPORATION RO WT HANOVER COMPANY WHITING-TURNER 5% 1% Revenue by Customer Type(1) 94% ■ Federal ■ State and Local $396mm 2023 revenue ■ Private ■ Federal ■ State and Local $316mm 2023 revenue 11#125 Clearly Defined Plan to Deliver Enhanced Growth and Returns Y ORION Bidding Discipline Focus on high-quality projects at healthier margins Expand Concrete business into Public Sector Construction New market for Concrete that diversifies portfolio from only relying on developers Fleet & Systems Upgrade Capex investments in fleet improvement, technology and = capabilities and systems to enhance business development Concrete Project Execution Focus on Dallas and Houston markets; exit Central Texas. Improved project management to drive margin expansion $$ Segment Integration Concrete & Marine have historically been siloed, and further integration will drive synergies and leverage best practices Talent Development Recruiting, developing and retaining talent through training and career advancement will reduce expense and mitigate risk over the long run New leadership's strategic vision will enhance stakeholder value 12#13Execution Against Three-Point Strategic Plan ORION Orion is capitalizing on industry dynamics and refocusing the business on high-margin services and projects 1 Achieved Profitability • . • in the Concrete Segment Achieved GAAP profitability in Q323 Focused business in core markets of Dallas and Houston; exited unprofitable Central TX market Implemented disciplined processes, changed leadership, added rigor in project delivery 2 Significant Contract Wins - Improved • Business Development $435M contract to build dry-dock in Pearl Harbor, HI $120M contract to build dry-dock in Grand Bahamas shipyard Building client relationships instead of only responding to bids Strong industry tailwinds: Infrastructure Bill; Port expansions; U.S. Navy buildout of Pacific facilities; Louisiana Coast 3 Investment and Resources Secured $103M ABL credit • facility; monetized $25M of • Attracted great talent to • non-core assets enhance business development and growth Future investments: ⚫ dredge infrastructure equipment 。 data analytics • geographic expansion through M&A 13#14wwwww ORION Financial Overview#15Financial Overview ($ in millions) Annual Revenue $748.3 $708.4 $709.8 $711.8 $601.4 2019 2020 2021 2022 2023 Revenue by Segment 44% 56% ($ in millions) $54.4 $39.6 Adj EBITDA ORION $22.9 $23.8 $17.3 2019 2020 2021 2022 2023 Adj EBITDA by Segment 13% 87% Backlog by Segment 21% 79% ■ Marine ■ Concrete ■ Marine ■ Concrete ■ Marine ■ Concrete Note: Financials as of 12/31/23. 15#16Fourth Quarter Financial Results Contract revenues up 3% to $201.6M from $196.2M in 4Q22 Operating income (loss) improved to ($0.6M) from ($3.5M) in 4Q22 Net income (loss) improved to ($4.4M) from ($4.9M) in 4Q22 Adjusted EPS improved to $0.08 from ($0.12) in 4Q22 Adjusted EBITDA improved to $14.8M from $3.2M in 4Q22 ORION Segment Revenue Adjusted EBITDA Marine +40% $11.3M vs. $4.9M in 4Q22 Concrete -33% $3.5M vs. ($1.8M) in 4Q22 16#17Balance Sheet and Liquidity December 31, 2023 ORION Cash & Cash Equivalents: $30.9M Net Debt Outstanding $37.2M Availability on Credit Facility $47.7M December 31, 2023 On December 1, 2023, Orion and White Oak amended Orion's credit facility to extend the maturity date for the $15.0 million pre-payment, and then on February 27, 2024, Orion and White Oak further amended the credit facility to lower the interest rate for the Company's $65 million revolver by 50 basis points and the Company's $38 million term loan by 100 basis points. As of 12/31/23, Orion monetized $25 million in sale leaseback transactions 17#18Compelling Investment Opportunity 6 5 Significant Upside Potential: Strong demand in both concrete and marine segments 1 Mission Critical Specialty Construction Provider with Sustainable Competitive Advantages 2 ORION Experienced New Management Team Focused on Improved Financial Performance ORION 3 Large Market Opportunity with Strong Tailwinds and Demand Drivers 3-Point Strategic Plan To Deliver Enhanced Growth and Returns 4 Diversified Revenue with Blue-Chip and Government Clients 18#19wwwww ORION APPENDIX#20Non-GAAP Supplemental Information Net Income to Adjusted Operating EBITDA Reconciliation Net loss Income tax (benefit) expense Interest expense, net Depreciation and amortization EBITDA (1) Stock-based compensation Net gain on Port Lavaca South Yard property sale ERP implementation Professional fees related to management transition Severance Intangible asset impairment loss Adjusted EBITDA(2) Operating income margin Impact of depreciation and amortization Impact of stock-based compensation Impact of net gain on Port Lavaca South Yard property sale Impact of ERP implementation Impact of professional fees related to management transition Impact of severance Impact of intangible asset impairment loss Adjusted EBITDA margin(2) Three months ended December 31, 2023 2022 ORION Year ended December 31, 2023 2022 $ (4,365) $ (4,949) $ (17,875) $ (12,612) (145) 33 330 429 3,972 1,510 11,556 4,352 6,996 5,631 23,878 24,057 6,458 2,225 17,889 16,226 209 639 2,042 2,754 (5,202) 568 308 1,378 1,867 1,118 683 4 809 948 6,890 6,890 $ 14,808 $ 3,176 $ 23,806 $ 22,913 (0.3)% (1.8)% (0.9)% (1.1)% 3.5 % 2.9 % 3.3 % 3.2 % 0.1 % 0.3 % 0.3 % 0.4 % - - % % (0.7)% — - % 0.3 % 0.2 % 0.2 % 0.3 % - % % - % 0.1 % 0.3 % - % 0.1 % 0.2 % 3.4 % % 1.0 % % 7.3 % 1.6 % 3.3 % 3.1 % ⚫EBITDA is a non-GAAP measure that represents earnings before interest, taxes, depreciation and amortization. •Adjusted EBITDA is a non-GAAP measure that represents EBITDA adjusted for stock-based compensation, net gain on Port Lavaca South Yard property sale, ERP implementation, professional fees related to management transition, severance and intangible asset impairment loss. Adjusted EBITDA margin is a non-GAAP measure calculated by dividing Adjusted EBITDA by contract revenues. 20