OSSA
OSSA is a Spanish specialist underground construction contractor, founded 1952 and majority-owned by Mercapital, delivering tunnels, shafts, and caverns across civil infrastructure, energy, and mining sectors in 15+ countries using a 400-unit specialized fleet.
- Company typePrivate
- Founded1952
- HeadquartersMadrid, Spain
- Headcount501–1,000
- GTM typeB2B
- OfferingServices
What OSSA does
OSSA (Obras Subterráneas, S.A.) is a privately held Spanish specialist underground construction contractor founded in 1952 and headquartered in San Sebastián de los Reyes, Madrid. Majority-owned by private equity firm Mercapital since July 2008, the company delivers tunnels, vertical shafts (up to 700m depth), large-scale caverns, metro lines, railway and roadway tunnels, and hydraulic infrastructure using a full range of methods including TBM, EPB shields, roadheaders, automated Jumbo drills, raise-boring, and drilling-and-blasting. With 501–1,000 employees and a fleet exceeding 400 specialized mechanical units, OSSA holds an estimated 30% share of Spain's underground construction market and has built more than 900 km of tunnels, 75,000 m of shafts, and 150,000 m of mine galleries over its history.
The company serves three primary end markets: civil infrastructure owners and developers (government agencies and metro/rail operators such as ADIF, Metro de Madrid, Generalitat de Catalunya, Metro Santiago de Chile, and Hong Kong MTR); energy and utility companies (Iberdrola, Endesa, AES, Naturgy) for underground hydroelectric plants; and multinational mining operators (CODELCO, Southern Peru Copper, Río Tinto, Fresnillo) for shaft, gallery, and mine-infrastructure works. Revenue is generated through project-based contracts—lump sum, unit price, target cost, or cost-plus—secured via public procurement, direct enterprise outreach, joint ventures (UTE) with general contractors, and specialist subcontracting. The majority of activity is international, with operations across more than 15 countries in Europe, Latin America, the Middle East, and Asia, and an international backlog of approximately $420M USD.
OSSA's business model combines deep technical specialization with capital-intensive plant assets, and is differentiated by 70+ years of accumulated know-how, ISO 9001/14001/45001/56001 certifications, and ESG credentials including consecutive Carbon Footprint Calculation Seals (2023–2024) and UN Global Compact signatory status. The company is actively investing in adjacent R&D through the UES365 underground energy storage consortium (compressed air, biogas, green hydrogen) and the UNDERAIBOT intelligent robotics project for underground inspection. Affiliate HISISA provides waterproofing services that extend OSSA's capture on each project. The firm operates as a specialist partner rather than a general contractor, frequently embedded in JV consortiums or as subcontractor to large international constructors (e.g., Webuild on NEOM in Saudi Arabia).
OSSA firmographics
Firmographics- Name
- OSSA
- Legal name
- Obras Subterráneas, S.A.
- Website
- https://ossaint.com
- Company type
- Private
- Founded year
- 1952
- Operating status
- Operating
- Headcount range
- 501–1,000 employees
- Short description
- OSSA is a Spanish specialist underground construction contractor, founded 1952 and majority-owned by Mercapital, delivering tunnels, shafts, and caverns across civil infrastructure, energy, and mining sectors in 15+ countries using a 400-unit specialized fleet.
- Ownership category
- akta.pro rank
Where OSSA is headquartered
LocationHeadquarters
- HQ city
- Madrid
- HQ country
- Spain
- HQ region
- Europe
Offices4 records
Markets served
OSSA business model
Business model- GTM type
- B2B
- Offering type
- Services
- Cost components
- Personnel, Supply Chain, Operations, Technology or R&D, Infrastructure, Marketing or Sales
Revenue model
- Construction Services Revenue: OSSA generates revenue through direct contracts for underground construction projects including tunnels, shafts, caverns, metro lines, and hydraulic infrastructure. Projects are billed at fixed contract values (lump sum, unit price, target cost, or cost-plus arrangements) upon completion of agreed milestones. The majority of activity is international, with projects across Europe, Asia, and Latin America.
- Specialist Subcontracting and Joint Venture Revenue: OSSA serves as a specialist partner in joint ventures (UTE in Spanish), providing technical tunnel engineering, manpower, and equipment to general contracting partners. Revenue is generated through specialist service contracts within larger infrastructure projects.
Go-to-market motion2 records
Distribution channels4 records
Marketing channels6 records
OSSA product offering
Product offeringCore offering
OSSA is a Spanish specialist contractor delivering end-to-end underground construction services, including tunnel excavation, vertical shaft drilling, and large-scale cavern construction for civil infrastructure (roads, railways, metros, hydraulic works), energy (hydroelectric power plants), and mining sectors. The company operates a fleet of over 400 specialized mechanical units and applies methods such as TBM, EPB shields, NATM, roadheader, and drilling and blasting.
Product overview
OSSA (Obras Subterráneas, S.A.) is a Spanish underground construction company offering specialized engineering and construction services across four core areas: Construction (roadway tunnels, railway tunnels, subway lines, hydraulic tunnels), Energy (hydroelectric power plants, large caverns, conduits), Mining (vertical shafts, access galleries, caverns for auxiliary services), and Services (technical assistance, waterproofing, installations). The company operates internationally with projects in over 15 countries, maintaining a fleet of over 400 mechanical units for excavation and underground works.
Differentiator
Problem solved
Functional benefit
Products and services
- Construction Civil engineering construction of roadway tunnels, railway tunnels, subway lines and stations, and hydraulic tunnels for government agencies and infrastructure developers.
- Energy Underground construction for hydroelectric power plants including large-scale caverns for generators, pressure pipe shafts, accesses, conduits, diversions, and restorations, for energy utilities and hydropower developers.
- Mining Underground mining works including vertical shafts, access galleries, and large-scale caverns for auxiliary services such as tanks, underground workshops, crushing plants, and pump rooms, for mining multinationals.
- Services Technical assistance for underground project execution, waterproofing through affiliate HISISA, and installation of lighting, electrical systems, safety systems, and ventilation for underground works.
Quantifiable outcome
- Over 900 km of tunnels constructed over the company's history
- +8 more outcomes
Companies that use OSSA
Customer profileNamed customers18 records
Segments4 records
Ideal customer profiles4 records
OSSA technology and API
TechnologyTechnology focussed No
API detail
- Has API
- No
- API docs
- API detail
Core technology
AI maturity
App detail
Feature3 records
OSSA partnerships and signals
Strategic signalPartnerships
16 partnerships are on record, tiered core.
- CRC Obras y ServicioscoreJoint venture partner (UTE) with OSSA for the Anglès bypass project (C-63 road), 483m tunnel for Infrastructures de la Generalitat de Catalunya.
- Rubau-Tarrés S.A.coreJoint venture partner (UTE) with OSSA for the Anglès bypass project (C-63 road), 483m tunnel for Infrastructures de la Generalitat de Catalunya.
- NTT DATA EUROPE & LATAM GREEN ENGINEERING, S.L.coreMember of the UES365 R&D consortium focused on underground energy storage using compressed air, biogas, and green hydrogen. The project has a total budget of €6,185,539 with €4,289,300 in CDTI funding. OSSA participates alongside 6 other companies and research institutions.
- H2B2 ELECTROLYSIS TECHNOLOGIES, S.L.coreMember of the UES365 R&D consortium focused on underground energy storage research using compressed air, biogas, and green hydrogen as energy vectors for renewable energy storage.
- SALMUERAS DEPURADAS, S.L.coreMember of the UES365 R&D consortium focused on underground energy storage using compressed air, biogas, and green hydrogen.
- TÚNELES Y GEOMECÁNICA, S.L.coreMember of the UES365 R&D consortium focused on underground energy storage systems. Contributes tunnel and geomechanical expertise to the project.
- GAS NATURAL COMERCIALIZADORA, S.A. (Naturgy)coreMember of the UES365 R&D consortium focused on underground energy storage. Provides energy commercialization perspective to the underground storage research.
- INERCO INGENIERÍA, TECNOLOGÍA Y CONSULTORÍA, S.A.coreMember of the UES365 R&D consortium focused on underground energy storage. Contributes engineering, technology, and consulting expertise.
- AlisyscorePartner in the UNDERAIBOT R&D project developing an embarkable kit for underground inspection using intelligent mobile robots with AI capabilities. Project CPP2022-009792 funded by MCIN/AEI and NextGenerationEU/PRTR.
- ITA · Instituto Tecnológico de AragóncorePartner in the UNDERAIBOT R&D project developing intelligent mobile robots for inspection of underground environments in construction and rescue situations.
- Grupo AzvicoreJoint venture partner with OSSA for the extension of Metro de Madrid Line 3 between Villaverde Alto and El Casar (2.6 km tunnel).
- COTODISA Obras y ServicioscoreJoint venture partner with OSSA for Metro de Madrid Line 3 extension and Villadangos del Páramo Storm Tank project (€6,839,093 awarded value).
- Source MachinerycoreGeneral contractor for whom OSSA serves as subcontractor on the Trojena B3 Tunnel project in Saudi Arabia's NEOM megaproject. Tunnel is 680m long.
- WebuildcoreGeneral contractor for whom OSSA serves as subcontractor on the Trojena B3 Tunnel in Saudi Arabia's NEOM megaproject.
- HISISAcoreOSSA's affiliate company specializing in waterproofing services. HISISA handles waterproofing on all OSSA projects and also serves third-party clients.
- AETOS (Asociación Española de Túneles y Obras Subterráneas)coreOSSA is an active member and sponsor of AETOS, participating in technical conferences including 'Marca España en obra subterránea' jornadas in Málaga, organized with the Ministry of Transport, ADIF, Junta de Andalucía, and Ayuntamiento de Málaga.
Scale indicators17 records
Recent moves7 records
Expansion highlights5 records
OSSA competitors and assessment
Company assessmentBroad incumbents
- Ferrovial: Spanish-headquartered global infrastructure operator and builder with strong tunneling capabilities (e.g., award of OSSA's Greek highway tunnel subcontract). Comparable as a Spanish-rooted infrastructure specialist, though much larger and more diversified than OSSA.
- Skanska: Swedish-based international construction group with a dedicated civil and underground works business serving metro, rail, hydro, and mining end markets in EMEA and the Americas. Comparable to OSSA as a sophisticated international tunneling competitor, though on a much larger scale and more diversified portfolio.
- Acciona Construcción: Large Spanish infrastructure and tunneling contractor that has executed major metro and hydro cavern projects. Comparable in the underground-construction domain and Spanish origin, though broader and less specialized than OSSA.
- Strabag: One of Europe's largest construction groups, with a significant tunnelling division delivering metro, railway, and hydro cavern projects internationally. Comparable to OSSA in the underground works segment but operates a much broader portfolio across construction, real estate, and infrastructure.
- Bouygues Travaux Publics: French-based division of Bouygues Construction specialized in complex civil and underground infrastructure projects including TBM-bored tunnels and underground stations. Comparable to OSSA in the underground-civil-engineering specialty and on joint venture rosters for major international projects.
- Dragados (ACS Group): Spanish tunneling and heavy-civil subsidiary of ACS Group with global underground works operations in transport, hydro, and mining. Comparable to OSSA in the tunneling specialty, but with greater scale and balance sheet capacity to lead multi-billion-dollar mega projects.
- Sacyr Ingeniería e Infraestructuras: Spanish construction and concessions group with significant underground works capabilities on transport and hydro projects. Comparable as another Spanish-rooted infrastructure contractor competing against OSSA for metro, rail, and road tunneling tenders.
Direct peers
- Implenia: Swiss-based specialist construction group with a dedicated tunnelling and underground business line executing complex metro, rail, and hydro cavern projects globally. Comparable to OSSA in the specialization, technique mix, and risk-sharing JV go-to-market for international underground works.
- Subterra: Spanish specialist underground contractor with deep experience in tunneling, shafts, and mining works. Closest direct peer to OSSA by geography, scope (NATM, TBM, conventional excavation), and primary customer base of public agencies and mining operators in Spain and Latin America.
- Webuild (formerly Salini Impregilo): One of the largest global tunneling and underground infrastructure contractors. Webuild partners with OSSA on the Trojena B3 tunnel in NEOM and is comparable in that both deliver complex TBM and shaft projects across transport, hydro, and mining end markets.
Market position
Strengths5 records
Weaknesses5 records
Competitive moat5 records
Key risks6 records
Key highlights7 records
Customer concentration
OSSA social profiles
Digital presenceOSSA compliance and trust
Trust signalCompliance5 records
OSSA financial estimates
Financial estimateRevenue estimate
Valuation estimate
OSSA leadership team
Management profileNumber of profiles
Profiles1 record
OSSA subsidiaries and ownership
Company hierarchySubsidiaries1 record
OSSA funding detail
Funding detailFunding overview
Funding rounds
Investors
Funding detail is available on the Subscription and Enterprise plan.Contact sales →
OSSA M&A and investment
M&A and investmentM&A
Investments
M&A and investment is available on the Subscription and Enterprise plan.Contact sales →
Frequently asked questions about OSSA
What does OSSA do?
OSSA is a Spanish specialist contractor delivering end-to-end underground construction services, including tunnel excavation, vertical shaft drilling, and large-scale cavern construction for civil infrastructure (roads, railways, metros, hydraulic works), energy (hydroelectric power plants), and mining sectors. The company operates a fleet of over 400 specialized mechanical units and applies methods such as TBM, EPB shields, NATM, roadheader, and drilling and blasting.
Is OSSA a public or private company?
OSSA is a private company. It is classified as private equity controlled and is currently operating.
When was OSSA founded?
OSSA was founded in 1952. It employs 501 to 1,000 people.
Where is OSSA based?
OSSA is headquartered in Madrid, Spain, in the Europe region.
How does OSSA make money?
Two revenue lines are on record. Construction Services Revenue is the primary driver. The others are specialist Subcontracting and Joint Venture Revenue.
Who are OSSA's main competitors?
Broad incumbents on record are Ferrovial, Skanska, Acciona Construcción, Strabag, Bouygues Travaux Publics, Dragados (ACS Group) and Sacyr Ingeniería e Infraestructuras. Direct peers are Implenia, Subterra and Webuild (formerly Salini Impregilo).
Does OSSA have an API?
No public API is recorded for OSSA.