Indefinite Delivery / Indefinite Quantity Contract (IDIQ)

Definition

An IDIQ contract (FAR Subpart 16.5) does not commit the agency to a specific quantity. Instead, the agency awards an IDIQ to one or more vendors with pricing, terms, and a contract ceiling in place. The agency then issues task orders (for services) or delivery orders (for products) as needs arise, drawing against the IDIQ contract. IDIQs typically run 5 years base with 5 optional years, have contract ceilings ranging from $1M for small business IDIQs to $50B+ for major DoD and civilian vehicles, and can be single-award (one vendor) or multiple-award (a pool of 5-500+ vendors who compete for each task order). Multiple-award IDIQs require agencies to give each pool member "fair opportunity" to compete under FAR 16.505.

When it applies

Used when the agency anticipates ongoing needs but cannot predict quantity or timing. Common in federal IT (CIO-SP4, Alliant 2, SEWP VI), professional services (OASIS, HCaTS), defense engineering (SETA support, ENCORE III), and base operations. Winning an IDIQ slot is often a multi-year revenue commitment but requires significant up-front bid investment — proposal costs of $250K-$2M are typical for large IDIQs. Once on an IDIQ, expect a 6-24 month lag before the first task orders start flowing. Small businesses win consistently on 8(a) STARS III, WOSB IDIQs, and reserved portions of multi-award vehicles.

Examples

• CIO-SP4 (NIH) — $50B, 10-year, 500+ awardee IT services IDIQ used by every federal agency.
• Alliant 2 (GSA) — $75B, 10-year unrestricted IT services IDIQ; small-business Alliant 2 SB is a separate $15B vehicle.
• OASIS (GSA) — $60B, 10-year professional services IDIQ across seven pools; being replaced by OASIS+ in 2026.
• SEWP VI (NASA) — $20B, 10-year IT products and hardware IDIQ used government-wide.
• 8(a) STARS III (SBA) — $50B, 10-year small-business IT IDIQ reserved for 8(a) firms.