Federal agencies buy most of what they need through government contract vehicles — pre-established agreements that let a contracting officer place orders without running a new competition from scratch. The main types are the GSA Multiple Award Schedule, Governmentwide Acquisition Contracts (GWACs), Multi-Agency Contracts (MACs), Indefinite Delivery Indefinite Quantity (IDIQ) contracts, Blanket Purchase Agreements (BPAs), and agency-specific vehicles. They differ in who can use them, what they cover, how orders flow, and what the contractor owes after winning a spot.
GSA Multiple Award Schedule
The Multiple Award Schedule, run by the General Services Administration, is the largest single contract vehicle in the federal government. In 2019 and 2020, GSA consolidated 24 separate schedules into one unified MAS covering products, services, and solutions across nearly every commercial category. The program is authorized under 41 U.S.C. 152 and governed by FAR Part 38, which sets up a streamlined process for buying commercial supplies and services at pre-negotiated prices.1Acquisition.GOV. 48 CFR Part 38 – Federal Supply Schedule Contracting
Contractors on the MAS list their offerings on two platforms. GSA Advantage is the online storefront where buyers browse catalogs and place orders directly.2Vendor Support Center. GSA Advantage GSA eBuy handles more complex needs: buyers post requirements and MAS contractors submit quotes electronically.3GSA eBuy. GSA eBuy Together they handle everything from routine supplies to multi-million-dollar service acquisitions without a fresh solicitation.
MAS contracts can run for up to 20 years total, longer than most federal vehicles.4Vendor Support Center. Contract Continuity – Streamlined Offer Process Contractors can request price adjustments during the term through the Economic Price Adjustment process; the contracting officer can accept, reject, or negotiate a different number, and approved changes apply only to orders placed after the modification takes effect.5Acquisition.GOV. Economic Price Adjustment – Federal Supply Schedule Contracts
Every MAS holder pays an Industrial Funding Fee of 0.75% of quarterly sales.6Vendor Support Center. Contract Sales Reporting My Sales Sales must be reported and the fee remitted within 30 calendar days after each quarter closes, including quarters with zero sales. GSA treats a missed payment as a contract debt, and repeated failures can end in termination.7Acquisition.GOV. Industrial Funding Fee and Sales Reporting
Governmentwide Acquisition Contracts
GWACs are reserved for information technology. The FAR defines a GWAC as a task-order or delivery-order contract for IT that one agency establishes for use across the entire federal government, run by an executive agent designated by the Office of Management and Budget under 40 U.S.C. 11302(e).8Acquisition.GOV. 2.101 Definitions That OMB designation is what separates GWACs from other interagency vehicles. Because the Economy Act doesn’t apply to GWAC orders, agencies can use them without the extra justification paperwork other interagency purchases require.
Active GWACs cover different slices of the IT market:
- Alliant 3 is GSA’s unrestricted IT services flagship. It went live in March 2026 with an ordering period through 2031 and a five-year option out to 2036, carries a 0.75% contract access fee, and has no ceiling on total value.9General Services Administration. Alliant 3
- NASA SEWP V covers IT products, communications, and audio-visual equipment. NASA has extended the ordering period through September 30, 2026, with potential further extensions into early 2027.10NASA SEWP. NASA SEWP Home
- 8(a) STARS III is a small business set-aside GWAC for IT services from a pool of 8(a)-certified partners.11General Services Administration. 8(a) STARS III
- VETS 2 is the only governmentwide IT vehicle set aside exclusively for service-disabled veteran-owned small businesses.12General Services Administration. VETS 2 Governmentwide Acquisition Contract
GWACs run on a task-order structure. The master contract sets the terms, ceiling, and vendor pool; when an agency has a specific need, it issues a task-order request and the contract holders compete for the work within the framework. That internal competition keeps pricing sharp while avoiding the months-long timeline of a full open-market solicitation.
On-Ramping and Off-Ramping
Many GWACs and other multiple-award vehicles build in ways to change the vendor pool mid-term. On-ramping lets the managing agency bring in new contractors to keep competition healthy, reach emerging technologies, or expand small business participation. The possibility of on-ramping must have been contemplated during initial acquisition planning and written into the original solicitation. Off-ramping is the counterbalance: contractors who stop competing, deliver unsatisfactory work, or no longer offer relevant solutions can be removed. Acquisition teams usually spell out the off-ramp criteria in the solicitation so contractors know the ground rules going in.13General Services Administration. On-Ramping Strategies for Multiple Award Vehicles
Multi-Agency Contracts
MACs are task-order or delivery-order vehicles that one agency sets up for use by other federal departments, covering a broader range of supplies and services than the IT-only GWACs. Before establishing a MAC, the sponsoring agency must prepare a business-case analysis showing the need, detailing administration costs, and analyzing the impact on existing vehicles, with approval consistent with guidance from the Office of Federal Procurement Policy.14Acquisition.GOV. Subpart 17.5 – Interagency Acquisitions
Legal authority for MAC orders depends on the vehicle. The Economy Act at 31 U.S.C. 1535 is the fallback when no more specific statute applies.15Office of the Law Revision Counsel. 31 USC 1535 – Agency Agreements Under an Economy Act order, the requesting agency must prepare a written Determination and Findings stating that the purchase is in the government’s best interest and that the supplies or services can’t be obtained as conveniently or cheaply through direct contracting. The D&F must identify a justifying circumstance, such as the servicing agency already holding a contract that covers the need or having specialized procurement expertise.16Federal Acquisition Institute. Contracting Professionals Smart Guide – Interagency Acquisitions
Indefinite Delivery Indefinite Quantity Contracts
The IDIQ is the structural backbone underneath many of these vehicles. GWACs and MACs are technically IDIQs. The defining feature is that the government doesn’t commit to a fixed quantity upfront. It sets a contract period and issues individual task orders or delivery orders as needs arise.17Acquisition.GOV. FAR Subpart 16.5 – Indefinite-Delivery Contracts
Every IDIQ must include a minimum order guarantee that is “more than a nominal quantity.” That minimum is what makes the contract legally binding, and it shouldn’t exceed what the government is fairly certain to order.18Acquisition.GOV. 16.504 Indefinite-Quantity Contracts Courts have occasionally found absurdly low minimums (say, $1,000 on a contract with a $500 million ceiling) effectively illusory, so contractors should read the minimum carefully before investing in a proposal.
IDIQs can be single-award or multiple-award. In a multiple-award arrangement, the contracting officer must give every contract holder a fair opportunity to compete for each order above the micro-purchase threshold. Orders above the simplified acquisition threshold, currently $350,000, require a formal competitive process with written notice and clear selection criteria.19Acquisition.GOV. 16.505 Ordering Limiting competition to a single holder is allowed only in narrow situations backed by written justification.
Blanket Purchase Agreements
BPAs work like charge accounts with pre-approved vendors. The agency and the vendor agree on terms and pricing upfront, but no money moves until someone places an order. BPAs are governed by FAR 13.303 and are designed to cut paperwork for recurring, relatively small purchases such as office supplies, routine maintenance, and IT accessories.20Acquisition.GOV. 48 CFR 13.303 – Blanket Purchase Agreements
There are two kinds. BPAs established under FAR Part 13 sit within simplified acquisition procedures and work best for purchases below the $350,000 threshold. Agencies can also establish BPAs against existing GSA Schedule contracts under FAR 8.405-3, which allows larger-dollar agreements with MAS vendors and gives buyers pre-competed pricing without standing up a separate contract. In both cases, the BPA itself doesn’t obligate funds; each call against it creates the spending commitment.
Agency-Specific Contract Vehicles
Some agencies build vehicles for their own use only. The Navy’s SeaPort-NxG is a well-known example, covering professional support services in areas like engineering and program management across the Navy’s system commands, Military Sealift Command, and the Marine Corps.21Naval Sea Systems Command. SeaPort NxG Navy acquisition regulations make SeaPort the mandatory consideration vehicle for those service categories, meaning contracting officers must look there first before going to the open market.22Department of the Navy. SeaPort Next Generation NxG
These vehicles use the same task-order mechanics as broader IDIQs but let the host tailor vendor qualifications, security requirements, and performance standards to its mission. The tradeoff for contractors: opportunities don’t always show up on centralized platforms. Vendors need to watch the individual agency portal and register in the relevant systems to see task-order solicitations when they’re released.
What Contractors Owe After the Award
Winning a spot on a vehicle is the start, not the finish line. Government evaluators rate contractors through the Contractor Performance Assessment Reporting System on factors including conformance to requirements, cost control, schedule adherence, business ethics, and customer satisfaction. Procurement officers review CPARS ratings before making new awards, so a poor evaluation on one vehicle can quietly close doors on the next. Contractors can review their own evaluations and submit comments disagreeing with the government’s assessment; access requires an active SAM.gov registration with Data Entry or Administrator role in the Entity Registration domain.23CPARS.gov. CPARS CPARS also captures integrity data such as terminations for default, suspension and debarment actions, and defective pricing findings.
Each vehicle also carries its own reporting and fee obligations. Schedule holders file quarterly sales reports and pay the IFF whether or not they made sales. GWAC holders pay a contract access fee, typically 0.75%, built into their pricing.9General Services Administration. Alliant 3 Missing these administrative obligations can escalate into termination, which then lands in CPARS and compounds the damage on the next competition.