SBIR Subcontracting Rules: The 33% Rule Explained

Every year, promising SBIR proposals are rejected for a reason that has nothing to do with the science. The company put too much work at a university. A consultant's hours pushed the subcontracting total past the threshold. The budget math was fine, the technology was compelling, and the proposal was dead on arrival because it violated the minimum work percentage rule. It is one of the most straightforward requirements in the SBIR program, and one of the most frequently misunderstood.

Here is exactly how it works, how to calculate it, and what to do when your project structure pushes against the limits.

The Core Rule: Who Must Do What

The SBIR program requires the small business applicant to perform a minimum percentage of the research and development work. For Phase I, the company must perform at least two-thirds — 66.67% — of the total work. For Phase II, the threshold drops to 50%. These percentages are measured by cost, not by hours or by effort.

STTR has different thresholds entirely, which is a frequent source of confusion. Under STTR, the small business must perform at least 40% of the work and the partnering research institution must perform at least 30%. The remaining 30% can be allocated to either party or to additional subcontractors. If your project involves a formal university collaboration, understanding whether you are applying under SBIR or STTR rules is the first decision that matters. The SBIR Complete Application Guide breaks down both program structures in detail.

These rules exist for a specific policy reason: Congress created SBIR to build R&D capacity inside small businesses, not to create a pass-through mechanism for university labs. Agencies enforce them accordingly.

How to Calculate Work Percentages

The calculation is based on the total contract cost minus profit (fee). Start with your total proposed budget. Subtract any profit or fee line item. The resulting figure is your total cost basis. Then add up every dollar going to subcontractors, consultants, and subawardees. That total must not exceed 33.33% of the cost basis for Phase I, or 50% for Phase II.

What counts as subcontracted work: any costs paid to entities or individuals outside your company. This includes university subawards, consultant fees, contract research organization charges, and testing services performed by external labs. It also includes materials or services purchased from a subcontractor if those costs are part of the R&D scope rather than standard supply purchases.

What does not count: direct materials and supplies purchased by the company, equipment purchases, and travel. These are direct costs of the prime contractor and count toward the company's work share.

A practical example: your Phase I budget is $275,000 with no profit. Your university subaward is $80,000 and you have a consultant at $15,000. Total subcontracted costs: $95,000, or 34.5% — over the limit by roughly $3,700. This proposal will be flagged.

For a broader look at who qualifies for SBIR under the reauthorized program, including ownership and affiliation rules that interact with subcontracting, see the eligibility rules breakdown.

What Happens When You Exceed the Limit

Exceeding the subcontracting threshold is not a minor administrative issue. Most agencies will reject the proposal outright during compliance review, before it ever reaches a technical panel. Some agencies will issue a request for clarification, but this is not guaranteed and depends on how far over the limit you are.

If the violation is discovered after award — for example, during an audit or a Phase II continuation review — the consequences are more severe. The agency can terminate the contract, require repayment of funds, or flag the company in the SBIR/STTR databases. For companies that intend to apply for future awards, a compliance violation is a serious mark.

The reauthorized SBIR program has also introduced stricter reporting requirements. Agencies are now required to verify work percentage compliance at project close-out, not just at proposal submission. This means that even if your initial budget is compliant, shifting work to subcontractors during execution can trigger a post-award violation.

Restructuring Your Budget to Stay Compliant

The most effective approach is to build the budget around the work percentage constraint from the start, rather than designing the project and trying to make the numbers work afterward. Here is how experienced SBIR applicants handle common scenarios.

University collaborations that are too large. If the university's scope of work requires more than 33% of Phase I costs, consider applying under STTR instead. STTR's 40/30 split was designed for exactly this situation. The PI can even remain at the university under STTR, which is not permitted under SBIR.

Key consultants pushing past the limit. If a critical consultant's fees, combined with other subcontractor costs, exceed the threshold, consider bringing them on as a part-time employee instead. An employee's salary counts toward the company's work share. Many SBIR companies hire key technical personnel at 10-20% effort specifically to keep them on the prime side of the ledger. The cost may be similar, but the compliance outcome is different.

Contract research organizations. If you are outsourcing assay development, testing, or manufacturing feasibility studies to a CRO, those costs are subcontractor costs. Evaluate whether any of that work can be performed in-house or whether the CRO scope can be reduced to keep the total under the cap.

Phase II planning. Phase II's 50% threshold is more generous, but budgets are also larger — typically $1 million to $1.7 million. The absolute dollar amount available for subcontracting is higher, which gives more flexibility for university partners and specialized testing facilities. Structure your Phase I to keep the most technically risky work in-house, and plan to expand the subcontracting scope in Phase II where the rules allow it.

STTR: When the Rules Work in Your Favor

For academic researchers considering a spin-out or for small businesses that genuinely need a deep university partnership, STTR's subcontracting structure is a significant advantage. The 30% minimum university work requirement is not just a ceiling — it is a floor that guarantees the research institution a meaningful role in the project. This makes STTR partnerships more attractive to university tech transfer offices, because the funding commitment is built into the program rules.

The tradeoff is that STTR requires a formal Cooperative Research and Development Agreement between the small business and the research institution. Negotiating IP terms, publication rights, and cost-sharing arrangements adds time to the proposal process. Start those conversations early — ideally three to four months before the submission deadline.

The SBIR/STTR program page has current solicitation links and agency-specific guidance on subcontracting documentation requirements, including the budget justification narratives that agencies use to verify compliance.

Related SBIR reading:

• SBIR Grant Guide 2026
• SBIR Budget Template: Line-by-Line
• Tips for Writing a Successful SBIR Proposal

Building a compliant budget that maximizes your technical team is one of the places where Granted can save you the most time, helping you structure work allocations and flag subcontracting issues before they become rejection reasons.