SBIR vs. STTR: what's the difference?

The Small Business Innovation Research (SBIR) and Small Business Technology Transfer (STTR) programs both fund early-stage R&D at U.S. small businesses through participating federal agencies. The key differences are about research partners and who does the work.

• STTR requires a formal partnership with a research institution (such as a university, a federally funded R&D center, or a nonprofit research institution). SBIR doesn't require one.
• Work split. Under STTR, the small business must do at least 40% of the work and the research institution at least 30%. Under SBIR, the small business does at least two-thirds of the work in Phase I and at least half in Phase II.
• Principal investigator. In SBIR, the PI must be primarily employed by the small business. STTR doesn't have this requirement; the PI can be employed by the research institution.
• Size of the programs. More agencies run SBIR than STTR. SBIR.gov lists 11 agencies in SBIR and 5 in STTR.

Both programs use the same three-phase structure (see Phase I vs. Phase II).

Official sources

• SBIR.gov – About the SBIR and STTR programs
• SBIR/STTR Policy Directive (SBA)

This guide is a plain-English summary, not legal advice. Rules change; the solicitation and SBA policy directive govern.