HORNBECK OFFSHORE SERVICES, INC.

Glossary of Terms Commonly Used in Our SEC Filings

"active utilization" means, when referring to OSVs or MPSVs, the weighted-average rate that active vessels are utilized, or generating revenue, based on a denominator comprised only of vessel-days available for service by the active fleet, which excludes the impact of inactive or stacked vessel days;

"Anti-Dilution Warrants" means the warrants that are issuable to holders of the Jones Act Warrants in the event that cash dividends are paid on the Company common stock, in order to preserve the economic value of the Jones Act Warrants;

"artificial intelligence (AI)" means an engineered system that analyzes large data sets to independently generate content, predictions, or decisions intended to achieve specific objectives and influence operations;

“ASC” means Financial Accounting Standards Board Accounting Standards Codification;

“ASU” means Accounting Standards Update issued by the Financial Accounting Standards Board;

“average dayrate” means average revenue per day based on the number of days during the period that the vessels, as applicable, generated revenue;

"average utilization" means, when referring to vessels, the weighted-average rate that such vessels are utilized, or generating revenue, based on a 365-day year;

"cabotage laws" means laws pertaining to the privilege of operating indigenous-flagged vessels engaged in domestic coastwise trade in the navigable waters of a nation (e.g. the Jones Act in the United States);

"Closing Date" means September 1, 2026, the closing date of the Merger;

“coastwise trade” means, with respect to the United States, the transportation of merchandise or passengers by water, or by land and water, between points in the United States, either directly or via a foreign port within the meaning of 46 U.S.C. Chapter 551 and any successor statutes thereto, as amended or supplemented from time to time;

"coiled tubing system" or "CT system" means a continuous length of steel tubing (CT), typically between 1” and 3.25” in diameter, wound onto a large reel together with an injector head, control console, power supply and well control stack. The CT is run inside a well’s production tubing primarily for debris cleanout, pumping fluids or fishing operations though there are numerous other applications;

“Company,” “Hornbeck,” “we,” “our” or “us” means Hornbeck Offshore Services, Inc., a Delaware corporation, and its subsidiaries;

"Creditor Warrants" means those certain warrants issued by the Company on September 4, 2020 pursuant to a warrant agreement of such date;

"C/SOV" means a multi-purpose support vessel that can be utilized in the offshore wind market, as either a CSOV or an SOV. A CSOV is a Commissioning Service Operation Vessel, typically serving during the commissioning and installation phases of an offshore wind farm, under contracts that are less than one year in duration. An SOV is a Service Operation Vessel, typically performing operations and maintenance services during the life of an offshore wind farm, under contracts that can be for multi-year terms;

"decommissioning" means the process of plugging and abandoning oil and gas wells and removing all associated infrastructure (pipelines, platforms, etc.). This is the final stage of oil and gas operations and typically occurs when all of the associated wells have reached the end of their useful production lives;

“deepwater” means offshore areas, generally 1,000’ to 5,000’ in depth;

“DP-1”, “DP-2” and “DP-3” mean various progressive classifications of dynamic positioning ("DP") systems on vessels to automatically maintain a vessel’s position and heading through anchor-less station-keeping;

“DWT” means deadweight tons;

“effective dayrate” means the average dayrate multiplied by the average utilization rate;

"Effective Time" means the effective time of the First Company Merger;

“First Company Merger” means the merger of Parent Sub with and into Legacy Hornbeck with Legacy Hornbeck surviving the First Company Merger as a wholly owned subsidiary of Legacy Helix, pursuant to and in accordance with the terms of the Merger Agreement;

“First Lien Revolving Credit Agreement” means that certain Credit Agreement dated as of August 13, 2024 (as amended by that certain First Amendment to Credit Agreement, dated as of December 27, 2024, by that certain Second Amendment to Credit Agreement, dated as of August 28, 2026, and by that certain First Incremental Facility Amendment, dated as of August 28, 2026 and effective as of September 1, 2026), originally entered into by and among Legacy Hornbeck, DNB Bank ASA, New York Branch, as administrative agent, Wilmington Trust, National Association, as collateral agent and collateral trustee, and the lenders party thereto, under which Hercules Sub became the borrower as successor to Legacy Hornbeck upon the closing of the Merger;

"First Lien Revolving Credit Facility" means our revolving credit facility established pursuant to the First Lien Revolving Credit Agreement;

“flotel” means on-vessel accommodations services, such as lodging, meals and office space;

"Gulf Island" means Gulf Island Shipyards, LLC;

"HADR" means humanitarian aid and disaster relief;

“Hercules Sub” means Hercules Sub LLC, a Delaware limited liability company and direct, wholly owned subsidiary of the Company;

“high-specification” or “high-spec” means, when referring to OSVs, vessels with cargo-carrying capacity of between 3,500 and 5,000 DWT (i.e., primarily 265 to 280 class OSV notations), and dynamic-positioning systems with a DP-2 classification or higher; for the avoidance of doubt, any MPSV is a high-spec vessel (other than MPSVs of greater than 5,000 DWT which are ultra high-spec Vessels);

"Hornbeck Brands" means various Hornbeck trade names and trademarks provided in the Fourth Amended and Restated Trade Name and Trademark License Agreement, which include “Hornbeck,” “Hornbeck Offshore,” “Hornbeck Offshore Services,” “HOS,” “HOSMAX,” “HOSS” and the Company's current horse head logos.

"Intervention Riser System (IRS)" means a subsea system that establishes a direct connection from a well intervention vessel, through a rigid riser, to a conventional or horizontal subsea tree in depths up to 10,000 feet. An IRS can be utilized for wireline intervention, production logging, CT operations, well stimulation, and full P&A operations, and provides well control in order to safely access the well bore for these activities;

"intervention system" means a subsea system that establishes a direct connection from a well intervention vessel to a subsea well in order to provide well control to safely access the well bore for well intervention activities. Intervention systems include Intervention Riser Systems (IRSs), Subsea Intervention Lubricators (SILs) and the Riserless Open-water Abandonment Module (ROAM);

"I-plough trencher" means a pre-lay plough spread with the capability to perform boulder clearance, pre-cut trenching and backfill services once the cable, umbilical or pipeline has been laid;

"IROV boulder grab" means a subsea grab tool with the capability to perform boulder clearance and debris removal;

“IRM” means inspection, repair and maintenance, also known as “IMR,” or inspection, maintenance and repair, depending on regional preference;

“Jones Act” means the U.S. citizenship and cabotage laws principally contained in 46 U.S.C. § 50501(a), (b) and (d) and 46 U.S.C. Chapters 121 and 551 and any successor statutes thereto;

“Jones Act-qualified” means, when referring to a vessel, a U.S.-flagged vessel qualified to engage in domestic coastwise trade under the Jones Act;

“Jones Act Warrant Agreement” means that certain Amended and Restated Jones Act Warrant Agreement, dated as of September 1, 2026, by and among Hercules Sub (as successor by merger to Legacy Hornbeck), the Company and Equiniti Trust Company, LLC, as warrant agent, pursuant to which the Jones Act Warrants are issued;

“Jones Act Warrants” means the Company’s warrants issued pursuant to the Jones Act Warrant Agreement;

"Latin America" means geographical areas of Mexico, Central America, South America and the Caribbean;

“Legacy Helix” means Helix Energy Solutions Group, Inc. prior to the completion of the Merger;

“Legacy Hornbeck” means Hornbeck Offshore Services, Inc., prior to the completion of the Merger;

"Merger" means the First Company Merger and the Second Company Merger, together;

"Merger Agreement" means that certain Agreement and Plan of Merger, dated April 22, 2026, by and among Legacy Helix, Parent Sub, Hercules Sub and Legacy Hornbeck;

“MPSV” means a multi-purpose support vessel, and we consider all of our MPSVs to be high-spec or ultra high-spec;

“OSV” means an offshore support vessel; also known as "PSV," or platform supply vessel, depending on regional preference;

“Parent Sub” means Odyssey Sub, Inc., a Delaware corporation and direct, wholly owned subsidiary of Legacy Helix prior to the Merger;

"plug and abandonment (P&A)" means operations usually consisting of placing several cement plugs in the well bore to isolate the reservoir and other fluid-bearing formations when a well reaches the end of its lifetime;

"Remotely Operated Vehicle (ROV)" means a robotic vehicle used to complement, support and increase the efficiency of diving and subsea operations and for tasks beyond the capability of manned diving operations. ROV also includes ROVDrill, a seabed-based geotechnical investigation system deployed with an ROV system capable of taking cores from the seafloor in water depths up to 6,500 feet;

"Riserless Open-water Abandonment Module (ROAM)" means a subsea system designed to act as a barrier to the environment during upper abandonment operations and during production tubing removal in open water, when run as a complement to an IRS. ROAM provides the ability to capture contaminants or gas within the system and circulate them back to the safe handling systems on board the vessel, such that no well contaminants are released into the environment;

“SAT" means the Mexican tax authorities;

"SEC" means the Securities and Exchange Commission;

"Second Company Merger" means the merger of Legacy Hornbeck, as the surviving corporation in the First Company Merger, with and into Hercules Sub one minute after the Effective Time, with Hercules Sub surviving the Second Company Merger as a wholly owned subsidiary of Legacy Helix, pursuant to and in accordance with the terms of the Merger Agreement;

"Second Lien Term Loan Credit Agreement" means that certain Second Lien Term Loan Credit Agreement entered into on December 27, 2024, (as amended by that certain First Amendment to the Second Lien Term Loan Credit Agreement dated as of August 28, 2026), governing our Second Lien Term Loans due 2033;

“Second Lien Term Loans due 2033” means Hercules Sub’s outstanding term loans under the Second Lien Term Loan Credit Agreement;

"site clearance" means activities utilizing ROVs for the safe removal of obstructions, such as boulders, unexploded ordnance (UXOs) and debris, that would inhibit the construction of an offshore wind farm;

"stacked" means the discretionary deactivation of a vessel through the removal of the full operating crew and strategic withdrawal of such vessel from active commercial activity;

"Subsea Intervention Lubricator (SIL)" means a riserless subsea system designed to provide access to the well bore while providing well control safety for activities that do not require a riser conduit. A SIL can be utilized for wireline, logging, light perforating, zone isolation, plug setting and removal, and decommissioning, and it facilitates access to subsea wells from a vessel to provide safe, efficient and cost effective riserless well intervention and abandonment solutions;

"Surety" means Zurich American Insurance Company and Fidelity & Deposit Company of Maryland;

"trencher or trencher system" means a subsea robotics system capable of providing post-lay trenching, inspection, burial and maintenance of submarine cables, flowlines and umbilicals in water depths of 30 to 7,200 feet across a range of seabed and environmental conditions;

“ultra-deepwater” means offshore areas, generally more than 5,000’ in depth;

“ultra high-specification” or “ultra high-spec” means, when referring to OSVs, vessels with cargo-carrying capacity of greater than 5,000 DWT (i.e., 300 class OSV notations or higher), and dynamic-positioning systems with a DP-2 classification or higher; for the avoidance of doubt, any MPSV of greater than 5,000 DWT is an ultra high-spec vessel; and

"well intervention services" means activities related to well maintenance and production management and enhancement services. Our well intervention operations include the utilization of slickline and electric line services, pumping services, specialized tooling and CT services.