SBIR eligibility has three distinct dimensions that most guides conflate: company ownership (the 51% rule), PI citizenship requirements (which vary by agency), and VC/investor rules. Getting any one wrong wastes months of work. In Cada's pipeline, eligibility confusion is the single most common reason companies abandon applications -- ahead of budget issues and timing.
This guide separates the three dimensions, covers them agency by agency, and includes the eligibility traps that catch founders who assume all SBIR programs work the same way.
The 5-minute eligibility pre-screen
Run through this before investing 40-100+ hours in an application.
| # | Check | What to Do if No |
|---|---|---|
| 1 | Is your company a for-profit entity? | Nonprofits and universities use different mechanisms (R01, R21), not SBIR. |
| 2 | Is >50% owned by US citizens or permanent residents? | Review your cap table. Convertible instruments don't count until converted, but upcoming conversions matter. |
| 3 | Do US citizens/PRs control the company (board seats, voting rights)? | Some term sheets give investors veto rights over key decisions -- if a foreign investor has those rights, the SBA may consider them to "control" the company even below 50% ownership. |
| 4 | Fewer than 500 employees (including affiliates)? | Parent company and subsidiary employees count toward your total. |
| 5 | Located in the US? | HQ and primary research performance must be in the US. |
| 6 | Does your PI meet the target agency's citizenship requirement? | See the agency table below. If not, find a US citizen/PR on your team for PI. |
| 7 | Will your PI be 51%+ employed by the company during the award? | University professors: likely need to reduce faculty appointment. |
| 8 | No single VC owns >50%? | If yes, check whether that VC is itself >50% US citizen/PR owned. |
| 9 | SAM.gov registration active? | Start now if not -- takes 2-4 weeks for new registrations. |
If you pass all 9 checks, you're eligible at most agencies. Read on for the agency-specific details and traps.
Dimension 1: company ownership (the 51% rule)
This dimension is universal across all SBIR agencies. The rules come from the SBA and apply regardless of which agency you target.
The core requirement: your company must be more than 50% owned AND controlled by US citizens or permanent residents. Ownership alone is not sufficient.
The SBA looks at both:
- Ownership: more than 50% of equity held by US citizens or permanent residents
- Control: the same individuals must control the company -- board seats, voting rights, and day-to-day management authority
A company where a US founder holds 51% of shares but a foreign investor controls the board through protective provisions may fail the "controlled by" test.
Common ownership situations
Convertible notes and SAFEs. Don't count toward ownership until they convert. But if your next round triggers conversion and drops US ownership below 51%, you become ineligible mid-award.
Foreign parent companies. A US subsidiary of a foreign-incorporated parent is generally not eligible, even if the US subsidiary operates independently. The SBA traces ownership to the ultimate parent.
Dual-class shares. If your company has voting and non-voting shares, the SBA looks at voting control separately from economic ownership. A founder with 51% economic ownership but minority voting rights may fail.
Affiliate rules. The 500-employee cap includes all affiliates. If you're a subsidiary, your parent's headcount counts.
Dimension 2: PI citizenship requirements (the agency split)
This is where most founders get tripped up. Unlike company ownership (universal), PI requirements vary significantly by agency.
| Agency | PI Must Be US Citizen/PR? | PI Employment Requirement | Key Notes |
|---|---|---|---|
| NIH | No | 51%+ employed by the company | PI can be any nationality. Must be employed at time of award. |
| NSF | Yes | 51%+ employed by the company | Strictest major agency. H-1B, O-1, L-1 holders cannot be PI. |
| DoD | Generally no | 51%+ employed by the company | Some topics require security clearances, which may need citizenship. |
| DOE | Generally no | 51%+ employed by the company | Some national lab partnership topics have restrictions. |
| ARPA-H | No | Employed by performing org | Some programs use OT authority with different rules -- check each solicitation. |
| NASA | Generally no | 51%+ employed by the company | Some ITAR-restricted topics require US persons. |
The critical difference: the same founder can be eligible at NIH but ineligible at NSF because of a single citizenship rule. A founder on an H-1B visa can serve as PI at NIH, DoD, and DOE -- but not at NSF. This one distinction is worth memorizing.
If you're a founder on a visa
- NIH: You can be PI. Visa status doesn't affect eligibility.
- NSF: You cannot be PI. Find a US citizen or permanent resident co-founder or employee.
- DoD: Usually fine, but check specific topics for clearance requirements.
- DOE: Usually fine. Some national lab topics have restrictions.
- ARPA-H: You can be PI, but expect additional scrutiny with foreign entity ties.
The 51% employment requirement
Across all agencies, the PI must be "primarily employed" by the small business during the award:
- At least 51% of professional effort at the company
- A university professor who is also a startup founder typically cannot be PI unless they reduce their appointment to <49%
- Employment must be in effect at time of award, not just at application
- For STTR: the PI can be employed by either the company or the research institution
Dimension 3: VC and foreign investor rules
SBIR has specific rules for companies with venture capital, hedge fund, or PE investors.
| Scenario | Eligible? | Details |
|---|---|---|
| Single VC owns <50% | Yes | Overall US citizen/PR ownership must still exceed 50% |
| Multiple VCs collectively own >50% | Yes | No single VC can own >50%. Each must be US-based. |
| Single VC owns >50% | Only if... | That VC is itself >50% owned by US citizens/PRs |
| Foreign VC owns minority stake | Yes | As long as overall US citizen/PR ownership stays >50% |
| Foreign VC owns majority stake | No | Fails the 51% US ownership test |
What counts as ownership: common and preferred stock, warrants (when exercisable), options (when exercisable), convertible instruments (when converted). SAFEs and convertible notes don't count until conversion.
The practical issue: most early-stage startups with US-based VCs are fine. Problems arise when a foreign VC leads a round that drops US ownership below 51%, or when a single US VC accumulates >50% through multiple rounds.
Before signing your next term sheet: check your post-money ownership against the 51% threshold. Restructuring after the fact is expensive and sometimes impossible.
Agency-specific eligibility traps
Beyond the three dimensions, each agency has quirks that catch founders who assume all SBIR programs work the same.
| Agency | Trap | What Happens | Severity |
|---|---|---|---|
| AHRQ | For-profit cannot lead | AHRQ's legislation prohibits for-profit lead applicants on ALL mechanisms. For-profit companies can only be subcontractors. Founders assume NIH rules apply because AHRQ shares grants.nih.gov. | Blocking |
| HRSA | Healthcare provider lead required | Many HRSA programs require a healthcare provider as lead applicant. Tech companies need a hospital or health system partner. | Blocking |
| USDA | Producer/rural entity lead | Some programs require agricultural producers or rural entities as lead. Tech companies need a qualifying partner. | Blocking |
| ARPA-H | Portfolio overlap = rejection | If ARPA-H already funds substantially similar work, your submission is automatically rejected. Research the current portfolio first. | Blocking |
| ARPA-H | SAM.gov + CAGE code required | Missing either is an administrative rejection. | Blocking |
| NSF | Innovation classification gate | NSF classifies innovations as A (new science), B (novel application), or C (engineering optimization). Category C gets score ceilings that make funding very unlikely. | Warning |
| DoD | Topic-specific only | You must respond to a specific open topic. No equivalent of NIH's omnibus FOA. If no topic matches, you can't apply. | Blocking |
| DoD | Security clearance topics | Some topics are ITAR or classified. Foreign nationals (including some PRs) may be restricted. | Warning |
| PCORI | Not an SBIR agency | PCORI has its own funding mechanisms. Included here because founders frequently mistake it for an SBIR pathway. | Warning |
| State programs | Residency/incorporation | Many require in-state incorporation or PI residency. Always verify per program. | Varies |
The big takeaway: never assume one agency's rules apply to another. AHRQ and NIH share the same grants portal but have different eligibility legislation. DoD and NSF are both SBIR but work completely differently. Check the specific solicitation for your target program every time.
SBIR reauthorization: 2026 status
As of March 2026, SBIR reauthorization has passed both chambers of Congress but is not yet signed into law. The program authorization lapsed September 30, 2025 -- the first lapse in its 43-year history. The reauthorization legislation (S. 3971, the Small Business Innovation and Economic Security Act) extends the programs through September 2031.
The core eligibility requirements in this guide are unchanged under the new legislation. New solicitations are expected to resume mid-2026 -- use this window to prepare (SAM.gov registration, team alignment, topic matching) so you're ready when they open.
The reauthorization adds enhanced foreign-affiliation screening for all awardees. If you have ties to foreign entities (particularly those from countries of concern), expect additional disclosure requirements. Check sbir.gov for the latest status.
When to get expert help
This guide covers the standard eligibility questions. The edge cases -- combinations of foreign-born founders, complex VC structures, and multi-agency applications -- require specific analysis.
If you're not sure whether your situation qualifies, answer that question first, before investing 40+ hours in a proposal. We've worked through eligibility issues with 200+ companies since 2023 -- including Series A startups with Canadian co-founders, VC-backed health AI companies flagged by AHRQ, and university spinouts with unresolved IP assignments. Our Strategy Review includes a full eligibility assessment specific to your corporate structure, team, and target agencies.