#1ORION Investor Presentation 2021 Annual Results#2Safe Harbor Statement The matters discussed in this presentation may constitute or include projections or other forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995, the provisions of which the Company is availing itself. Certain forward-looking statements can be identified by the use of forward-looking terminology, such as 'believes', 'expects', 'may', 'will', 'could', 'should', 'seeks', 'approximately', 'intends', 'plans', 'estimates', or 'anticipates', or the negative thereof or other comparable terminology, or by discussions of strategy, plans, objectives, intentions, estimates, forecasts, outlook, assumptions, or goals. In particular, statements regarding future operations or results, including those set forth in this presentation, and any other statement, express or implied, concerning future operating results or the future generation of or ability to generate revenues, income, net income, profit, EBITDA, EBITDA margin, or cash flow, including to service debt, and including any estimates, forecasts or assumptions regarding future revenues or revenue growth, are forward-looking statements. Forward looking statements also include estimated project start date, anticipated revenues, and contract options which may or may not be awarded in the future. Forward looking statements involve risks, including those associated with the Company's fixed price contracts that impacts profits, unforeseen productivity delays that may alter the final profitability of the contract, cancellation of the contract by the customer for unforeseen reasons, delays or decreases in funding by the customer, levels and predictability of government funding or other governmental budgetary constraints and any potential contract options which may or may not be awarded in the future, and are the sole discretion of award by the customer. Past performance is not necessarily an indicator of future results. In light of these and other uncertainties, the inclusion of forward-looking statements in this presentation should not be regarded as a representation by the Company that the Company's plans, estimates, forecasts, goals, intentions, or objectives will be achieved or realized. Readers are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date hereof. The Company assumes no obligation to update information contained in this document whether as a result of new developments or otherwise. Please refer to the Company's Annual Report on Form 10-K, filed on March 7, 2022, which is available on its website at www.oriongroupholdingsinc.com or at the SEC's website at www.sec.gov, for additional and more detailed discussion of risk factors that could cause actual results to differ materially from our current expectations, estimates or forecasts. BIG 808 AVELL ORION 2#3Core Values Consistent with Strategy 啗 We take pride in our personal workmanship and that of the entire organization; we are committed to ensuring that each task is properly performed the first time and we will continuously improve upon everything we do every day We are responsible and accountable for our own personal safety; we are equally responsible for the safety of all our coworkers and any others we come into contact with; and we are authorized to and obligated to stop work whenever an unsafe condition, or situation is observed ORION Quality Production Safety Integrity We are committed to performing assigned tasks in the most efficient, timely and cost effective manner; we expect employees to safeguard company assets; and we always act in the best interest of the company The foundation of our success rests upon integrity; we view integrity as our ability to be honest, ethical, sincere and forthright in our dealings with others; we will apply the foundation of integrity in everything we do; and when the Company makes a commitment, that commitment must be kept 3#4Company Overview Orion Group Holdings, Inc., a leading specialty construction company, provides services in the Infrastructure, Industrial, and Building sectors through its marine construction segment and its concrete construction segment in the continental United States, Alaska, Canada and the Caribbean Basin. NYSE: ORN Headquarters: Houston, Texas # of Employees: ~2,500 Market Cap: ~$117 million* . ORION Average project duration: 6-9 Months Book value per share $4.79 Services Broad range of marine construction including marine transportation facility construction and dredging services Concrete construction services including light commercial, structural and industrial services Customers . • Federal, State, Municipal Governments (30% of Revenue in 2021) Private commercial and industrial clients (70% of Revenue in 2021) *as of 12/31/21 ORION Competition Marine Concrete 64% 44% 56% 36% • Highly fragmented market • Barriers to entry • Local, regional, and national competitors 2021 Revenue 2021 Backlog Financials (2021) • $601.4 MM Revenue $17.3 MM Adj. EBITDA $590.0 MM Backlog (12/31/21) 4#5Investment Highlights Diverse end markets with favorable macro trends · . Unique turnkey project capabilities Specialized fleet of equipment. creates barriers to entry and a competitive advantage Results reflect impact of operational transformation improvements in labor efficiency and equipment utilization ORION 5#6Attractive Geographic Footprint = Headquarters ORION 6#7Favorable Macro Drivers Across Business Segments Marine • Port expansions and maintenance Downstream energy • Bridges and causeways • Marine infrastructure • Coastal rehabilitation ORION Concrete • • • Distribution center development Institutional developments and expansion Structural developments Recreational developments Industrial developments 7#8Marine Segment Capabilities Marine Transportation Facility Construction Port Facility Wharves Cruise Ship Terminals Dredging Services Marine Construction Wildlife Refuge Creation Electric Capabilities • Bulkheads Military Installations Liquid Cargo Terminals Intracoastal Waterway Maintenance Reclamation Hurricane Restoration • Piers Dry Bulk Terminals Container Terminals Docks Marinas • Port Expansion Port Deepening Beach Nourishment Marine Environmental Structures Shoreline Protection Environmental Remediation GeoTube® Installation Wetlands Creation Concrete Mattress Installation Sea-Grass Bed Creation Erosion Control Levee Installation Marine Pipeline Construction Pipeline Anchoring Communication Pipeline Tie-ins Cool Water Intakes Effluent Discharge Outfalls Intakes Velocity Control Structures Outfalls Hot-taps Transmission Pipelines Risers Jetting Specialty Services ORION Heavy Lift Diving Towing Inspections Demolition Surveying • Encapsulation Repair Salvage 8#9Fleet of Specialized Marine Equipment Around 800 Vessels & Pieces of Equipment • 36 spud and material barges ⚫ 17 tug and push boats • 5 operational cutter suction dredges • ~700 pieces of other equipment • 36 crawler and hydraulic cranes Spud Barges 6 1PA 109 THE Dredge Fleet Tug and Push Boats ORION Cranes and Other Equipment $1.76 Marine Book Value per Share Estimated Replacement Value of Over $200 million 9#10Commercial Concrete Construction Overview One of the Largest Texas-based Concrete Contractors • • Concrete construction primarily driven by population growth Houston, Dallas and Austin are three of top ten growing metro cities in the US Significant market share in Houston Expanded to Dallas/Ft. Worth market in 1995 Expanded to Austin market in 2017 Provides turnkey services covering all phases of commercial concrete construction • Acquired in 2015 ORION 10#11Breadth of Concrete Services Provides Services Across Three Avenues: • . Light Commercial - Horizontally poured concrete, tilt-walls, trenches, rebar installation, and pumping services Structural - Elevated concrete structures, with columns, elevated beams, walls, and slabs Industrial - Warehouses, distribution, manufacturing facilities, water treatment plants 123 4,000+ 12 Yr. 85% Avg. Projects Annually* Completed Projects Avg. Customer Tenure Repeat Business *calculated over most recent 5-year period ORION 11#12High Quality Customer Base Marine Segment Concrete Segment Federal Government Customers USDA US Army Corps of Engineers State Government Customers DOID - P 18: DEV \VDOT Local Government Customers PHA Private Customers Carnival SONEL Department of Transportation PORT CANAVERAL TAMPA PORT AUTHORITY A Oiltanking BOSTCO STORAGE & TERMINAL SERVICES 2021 Revenue by Customer Private 38% ORION ConocoPhillips Federal 21% State 2% Local 40% DYAD CONSTRUCTION... Turner EEREED CONSTRUCTION, L. P. HOAR CONSTRUCTION 2 MYCON HARVEY HARVEY.. CLEARY 2021 Revenue by Customer Private 96% MISSION CONSTRUCTORS, INC. Gilbane Metzger S&P SATTERFIELD & PONTIKES CONSTRUCTION, INC. Local 4% O 12#13Recent Projects Won Project Segment Location Value Start Date Design and Construction Marine Bahamas $28 Million Q2'22 Mixed Use Construction Concrete Texas $9 Million Q1'22 Channel Dredge Marine Texas $7 Million Q1'22 Storage Construction Concrete Texas $6 Million Q1'22 Bulkhead Wall Install Marine Florida $5 Million Q1'22 Rehabilitate Barge Marine Texas $4 Million Q1'22 ORION 13#14($ in millions) Year Ending Back Log Levels ORION ■YE Concrete Backlog ■YE Marine Backlog $558.5 $590.0 $438.6 $439.5 $326.9 $376.9 $202.6 $254.9 $231.6 $236.9 $213.1 $183.7 2018 2019 2020 2021 14#15Expansion in Industrial Sector Orion Capabilities Existing New Service Structural Excavations & Backfill Foundations (Drive, Piles, Pile Caps, Footings, Piers) Form/Concrete/Rebar Columns/Pipe Supports/Walls ✓ ✓ Slab-on-grade and Paving ✓ ✓ Elevated Concrete Hoisting Utilities, Waterproofing & Coatings *represents scopes of work that will be subcontracted. ORION CAT ✓* GE The industrial sector represents a broad range of opportunities for our company. By leveraging our skill sets and customer base, we are expanding our addressable markets to provide high-quality services to meet more of our customers needs. 15#16Recent Annual Results ($ in thousands except EPS data) 2019 2020 2021 Contract Revenues $708,390 $709,942 $601,360 Operating Income $2,193 $26,586 ($9,317) Adjusted EBITDA $39,550 $54,423 $17,299 Adjusted EPS $0.00 $0.47 ($0.35) Operating Cash Flows ($716) $46,032 $69 ORION 16#17Recent Quarterly Results ($ in thousands) Q4 2021 Q4 2020 Variance Contract Revenues $162,269 $170,176 (5%) Operating Income ($8,195) $5,052 (262%) Adjusted EBITDA $815 $12,651 (94%) Adjusted EBITDA Margin (%) 0.5% 7.4% (688 bps) Contract Revenues were down due to: Operating Income decreased due to: Lag effects from COVID-19 pandemic in the marine segment as well as impacts from Omicron variant in the latter part of the quarter Volume of work decline in marine business as a result of the COVID-19 pandemic Lag effect from COVID-19 pandemic which pressured project margins in concrete segment ORION 17#18Liquidity to Fund Operations As of December 31, 2021 ($ in millions) Cash and equivalents $12.3 Current Assets $197.9 Working Capital $36.2 Total Assets $351.8 . Current Liabilities $161.7 · Total Debt* ● $39.4 • Total Liabilities $203.7 Shareholder's Equity $148.1 *net of debt issuance cost ORION CAT HITACH Conservative Balance Sheet Strong Liquidity Position Access to Capital Markets Bonding capacity at least $750 million 18#19Appendix EBITDA/Adjusted EBITDA reconciliation ORION 19#20Adjusted EBITDA and EBITDA Margin Reconciliation ($ in thousands) 2013 2016 2017 Contract Revenue Net income (loss) Income tax Interest expense, net Depreciation and amortization EBITDA (1) Stock-based compensation Changes in cost estimate 2014 2015 2021 354,544 385,818 466,498 578,236 578,553 520,894 708,390 709,942 601,360 $331 $6,877 ($8,060) ($3,620) $400 ($94,422) ($5,359) $20,220 ($14,560) ($937) $3,175 ($2,519) $1,581 ($4,541) ($12,233) $1,868 $502 $512 $677 $3,116 $6,172 $5,720 $7,807 $6,455 $21,538 $23,451 $28,083 $34,162 $29,491 $31,799 $28,407 $21,444 $34,180 $20,620 $38,295 $31,070 ($67,049) $31,371 $2,141 $1,594 $2,277 $2,280 $2,303 $2,240 $2,753 $22,770 2018 2019 2020 $1,976 $4,737 $4,940 $27,217 $25,430 $54,150 $16,312 $1,998 $2,401 Reserve on disputed AR $4,280 ($898) -- $69,483 Goodwill impairment charges Legal settlement ERP implementation ISG initiative Severance Insurance recovery on disposal of asset ($5,448) -- -- $1,488 $4,925 $4,781 $369 $645 $175 $96 -- -- ($2,859) Tampa Property Sale -- (6,435) Adjusted EBITDA $23,585 $35,774 $22,897 $40,575 $33,373 $26,276 $39,550 $54,423 $17,299 Profit margin (2) Impact of income taxes 0.09% (0.26%) 0.82% 1.78% (1.73%) (0.63%) 0.07% (1.81%) (0.76%) 2.85% (2.42%) (0.54%) 0.27% (0.78%) (2.34%) 0.26% 0.28% 0.08% Impact of interest expense, net 0.14% 0.18% 0.67% 1.07% 1.00% 1.50% 0.91% 0.67% 0.82% Impact of depreciation and 6.07% 6.08% 6.02% 5.91% 5.10% 6.10% 4.01% 3.83% 4.23% amortization Adjusted EBITDA margin (1) 6.65% 9.27% 4.91% 7.02% 5.77% 5.04% 5.58% 7.67% 2.88% ORION (1) EBITDA and Adjusted EBITDA are non-GAAP measures that represents earnings before interest, taxes, depreciation and amortization. Adjusted EBITDA margin is a non-GAAP measure calculated by dividing Adjusted EBITDA by contract revenues. (2) Profit margin is calculated by dividing Net income (loss) by contract revenue 20 20