Government Contract Vehicles: GSA MAS, GWACs, MACs, and OASIS+ Explained for 2026

A contract vehicle is a pre-competed umbrella agreement that lets agencies place orders without running a full competition every time they need something. The government vets a pool of contractors once — checking their past performance, financial stability, and technical capabilities — then issues task orders or delivery orders against that pool for years.

Think of it as getting your vendor card punched. Without a seat on the right vehicle, agencies can't buy from you even if they want to. With a seat, you're on the shortlist every time they need what you do.

In FY2025, vehicles accounted for $72.4 billion — 8.6% of total federal contract awards. That fraction has grown every year for a decade as agencies consolidate purchasing under vehicles to reduce administrative burden and improve oversight. An Executive Order on Procurement Consolidation issued in early 2026 is pushing the number higher still, requiring agencies to use GSA-managed vehicles like OASIS+ and Alliant 3 rather than standing up duplicative agency-specific contracts.

Vehicles create a tiered market. Open-market competition is where newcomers start. Contract vehicles are where established contractors generate predictable, recurring revenue with lower bid-and-proposal costs per dollar won.

Federal contracting vehicles come in four forms, and knowing the difference matters because the application process, the competition rules, and the revenue potential vary significantly between them.

The key distinction that trips up new contractors is "who can order." A GWAC like Alliant 3 is usable by any civilian federal agency. An agency-specific IDIQ MAC — like the Army's ITES-3S — is only usable by Army buyers. If you win a seat on a narrow agency contract, you're locked into one customer's buying patterns.

GWACs and the GSA MAS are where you want to be for market reach. Agency-specific vehicles are worth pursuing when you have a strong incumbent position or deep relationships at a particular agency.

The GSA Multiple Award Schedule — officially called the GSA MAS, and formerly known as the Federal Supply Schedule or GSA Schedule — is the federal government's primary commercial purchasing program. In FY2025, agencies bought $51.5 billion worth of products and services through it.

The MAS works like a commercial catalog with pre-negotiated pricing. GSA approves contractors and sets pricing ceilings based on commercial price lists. After that, ordering agencies can buy directly up to $25,000 without any competition among Schedule holders. Above $25,000 they need to get at least three quotes from Schedule contractors. Above $250,000, they need to document the market research more formally — but it's still far faster than a full open-market competition.

The MAS covers 12 large categories: IT, professional services, facilities, industrial, human capital, transportation, security, marketing, office management, scientific management, environmental, and travel. Within those, there are hundreds of sub-categories called Special Item Numbers (SINs) — each one a specific type of product or service.

One overlooked MAS feature: state and local governments can buy through it under the Cooperative Purchasing Program. If you're building a state-and-local pipeline alongside federal, a GSA Schedule serves both markets. Read more on expanding beyond federal in our state and local contracting guide.

Government-Wide Acquisition Contracts (GWACs) are IDIQ contracts managed by GSA or NASA for IT services. Unlike the MAS, GWACs are primarily for services — complex IT system development, cybersecurity, cloud infrastructure, AI development — and tend to be larger, more complex task orders than typical Schedule buys.

GWACs require agencies to use them rather than stand up competing vehicles, which makes GWAC holders more valuable over time. The current major GWACs are:

GWACs matter because agencies are mandated to use them. An IT contractor without a GWAC seat — or without a teaming relationship with a GWAC holder — is locked out of the agency's preferred procurement path. Read our detailed SEWP guide and the MAC strategy guide for deeper dives on each.

OASIS+ (One Acquisition Solution for Integrated Services Plus) is GSA's professional services GWAC — the equivalent of Alliant for non-IT services like program management, logistics, financial management, scientific research, environmental services, and facilities management.

OASIS+ has no contract ceiling. That was a deliberate design choice: the original OASIS hit its ceiling limits and agencies couldn't order through it, which created procurement chaos. The + version removes the ceiling entirely.

The six OASIS+ pools are: Unrestricted (large and small), Small Business, 8(a), HUBZone, WOSB, and SDVOSB. If you hold two or more certifications — say, you're an SDVOSB that's also HUBZone-certified — you can pursue multiple pools simultaneously, giving you more seats and more visibility to ordering agencies.

The 13 Domains in Phase II cover: Program Management, Logistics, Financial Management, Scientific and Engineering, Environmental, Facilities, Intelligence Services, Data Management, Language Services, Security and Mission Support, Training, Health and Biomedical, and Legal Services. If your work touches any of these areas, OASIS+ is probably the right vehicle to pursue.

Our federal procurement forecast guide covers how to use agency forecasts to identify which OASIS+ domains are getting the most task-order activity at specific agencies — useful for prioritizing proposal investments.

Several vehicles are reserved entirely for small businesses. Agencies using these vehicles are required to award to small firms — large businesses can't compete, can't prime, and can't use their subcontractors to qualify. These are among the highest-value seats in federal contracting.

Agency-specific small-business MACs add another layer. The Army's ITES-3S, the Navy's SPAWAR vehicles, GSA's IT Schedule 70 (now part of MAS IT category) — these are supplementary rather than substitutes for the GWACs above. They're worth adding once you have a GWAC seat; they're not the place to start.

You can't pursue every vehicle — each application costs real money, and proposal work for a major GWAC can run $50,000–$200,000 in internal effort. Here's the framework for prioritizing:

The CapturePilot Intelligence module tracks historical spending by vehicle, agency, and NAICS code. Before you commit months to a vehicle proposal, verify that agencies actually spend money on your specific service area through that vehicle — not just that the vehicle theoretically covers your NAICS code.

The application process varies significantly by vehicle type. Here's what to expect at each level:

Use our proposal color team review guide and the proposal template to structure major GWAC submissions — the evaluation criteria for vehicles are typically well-documented in the solicitation and should drive every section you write.

Getting on a vehicle is the first competition. Winning task orders is the second — and it's the one that generates actual revenue. Here's the reality: 10% of contractors with GWAC seats capture most of the spending. The rest hold unused seats.

Task orders under GWACs and MACs are competed among the vehicle's contract holders. Agencies issue a Request for Task Order Proposal (RTOP) or Request for Quote (RFQ) — like a mini-RFP — and pick from the pool. The advantage over open-market competition is speed (agencies can get quotes in days rather than weeks) and cost (you're already vetted, so the evaluation is narrower).

Read our full guide on using debriefings to improve your win rate — the same principles apply to task-order losses as to prime contract losses.

Most companies that spend money on vehicle proposals and never generate revenue make one of the same five mistakes.

The bid/no-bid decision framework applies here too. A vehicle proposal is a bid — apply the same strategic filter before you invest. The CapturePilot Intelligence module surfaces the data you need to make that call: historical task-order frequency, average award value by vehicle and agency, and small-business award rates on each vehicle.