| Rule | SBIR | STTR |
|---|---|---|
| Participating agencies | 11 (DoD, NIH, NSF, DoE, NASA, USDA, DHS, DoT, DoC, EPA, ED) | 5 (DoD, NIH, NSF, DoE, NASA) |
| Academic subaward required? | No (allowed up to 1/3 in Phase I) | Yes — at least 30% to a non-profit research institution |
| Small business work share (Phase I) | At least 2/3 (~67%) | At least 40% |
| Phase I award size | ~$150k–$314k | ~$150k–$314k |
| Phase II award size | ~$1M–$2M | ~$1M–$2M |
| Principal investigator employer | Must be primarily (>50%) employed by the small business | Can be primarily employed by either the small business OR the research partner |
| IP allocation | Negotiated; default is small business owns | Must be negotiated between small business and research institution up front |
| Best for | Independent small businesses with internal R&D capacity | University spinouts; PIs who want to keep an academic appointment |
You're an established small business (5–50 employees), you have in-house R&D capacity, and adding a university subaward would slow you down. SBIR keeps the work and IP under one roof. The 2/3 small- business-work rule fits firms that do their own bench science.
You're a university spinout, the PI is still on faculty, or your critical IP is in a professor's lab. STTR formalizes the academic partnership and lets the PI keep a >50% academic appointment. The 30% subaward minimum is a feature, not a bug, if your science depends on campus equipment or grad students.
Five of the 11 SBIR agencies also run STTR: DoD, NIH, NSF, DoE, and NASA. The other six (USDA, DHS, DoT, DoC, EPA, ED) run SBIR only.
It depends. STTR has a smaller applicant pool (fewer programs, partnership requirement filters out many firms) but the academic- subaward requirement adds administrative complexity. For university spinouts with an existing research partner, STTR is easier. For independent small businesses, SBIR has fewer compliance hurdles.
No. You apply to one or the other for a given project. You can have separate SBIR and STTR projects running in parallel, but a single project cannot be submitted under both program designations.
For SBIR, the principal investigator (PI) must be primarily employed by the small business (>50% time). For STTR, the PI can be primarily employed by either the small business or the partnering research institution — a significant flexibility for university faculty who want to keep their academic appointment.
Yes. TopicScout indexes both SBIR and STTR open topics from all 11 participating agencies. The weekly digest tags each topic SBIR or STTR so you know which program rules apply before you start a proposal.