Phase II vs. Phase III SBIR: What Actually Changes Between Them
Phase II finishes a prototype. Phase III commercializes it. The contracting mechanics are completely different — different authority, different funding source, different rules.
Phase II completes the prototype with SBIR funding. Phase III commercializes the result with non-SBIR funding, under sole-source authority, with no dollar cap and no time limit. They are different contracting mechanisms, not stages of the same one.
The teams that get to Phase III consistently treat Phase II as the start of customer development, not the end of an R&D project. The mechanical differences between Phase II and Phase III matter, but the more important shift is between proposal-writing and contract-file work. They are different muscles, and most awardees only build the first one.
"Phase II" and "Phase III" sound like consecutive steps in the same process. They are not. They are different contracting mechanisms with different funding sources, different authorities, different award processes, and different rules. The transition from one to the other is one of the hardest moves in the federal contracting system, and the difficulty is largely a function of the fact that most people approach Phase III as if it were Phase II Plus.
The defining differences.
Side by side, here is what actually changes between Phase II and Phase III:
| Dimension | Phase II | Phase III |
|---|---|---|
| Funding source | SBIR/STTR set-aside | Any federal appropriation |
| Award process | Competitive | Sole source |
| Dollar ceiling | Capped per agency | No cap |
| Time limit | Period of performance defined | No time limit on when it must be awarded |
| Work type | R&D / prototyping | Any work that derives from, extends, or completes |
| Required documentation | Full SBIR proposal, evaluation | D&F + DEC statement + price analysis |
| Issuing agency | Funding agency | Any federal agency |
Why this trips people up.
Most companies that get to Phase II have built a process for winning Phase II: scan SBIR.gov, watch for relevant topics, write a strong proposal, respond to evaluator feedback, win. That process does not produce a Phase III. Phase III is not on SBIR.gov. There is no solicitation. There is no evaluation panel. The "winning move" is convincing a federal customer to use their non-SBIR funding to buy the technology your Phase II built, and equipping their contracting officer with the documentation to do it sole-source.
Teams that succeed at Phase III usually have to rewire how they think about federal capture. The unit of work shifts from "proposal" to "customer relationship plus contract file." The cycle shifts from solicitation cycles to budget cycles. The reviewer shifts from a source-selection authority to a contracting officer and their legal counsel.
The funding shift is the biggest practical change.
Phase I and Phase II are funded out of each agency's SBIR set-aside — a dedicated pool that exists specifically for that program. Phase III is not. It is funded out of whatever appropriation the customer has available: O&M (operations and maintenance), RDT&E (research, development, test, and evaluation), procurement, working capital. This is a different conversation. The customer has to find money in their actual budget, which means the work has to be on their priority list — not on the SBIR program office's priority list.
This is why "make the transition low-risk for the customer" is the most repeated piece of Phase III advice. If you are asking a program office to spend their O&M on your technology, you are competing with everything else that program office could spend O&M on.
What is the difference between Phase II and Phase III SBIR?
Phase II completes the R&D and prototype work funded by SBIR/STTR dollars. Phase III commercializes the result through a contract awarded under SBIR Phase III sole-source authority. Phase II is competitively awarded; Phase III is not. Phase II has a dollar cap; Phase III does not.
Can Phase III be funded with SBIR/STTR dollars?
No. Phase III is funded with non-SBIR dollars from any federal source — agency O&M funds, RDT&E, procurement, working capital, or any other appropriation. SBIR set-aside funding is reserved for Phase I and Phase II.
Does the same agency that funded Phase II have to issue my Phase III?
No. Any federal agency can issue your Phase III based on your Phase I/II SBIR work. Cross-agency Phase III awards are explicitly allowed by the statute.
Does Phase III have to be R&D?
No. Phase III work does not have to be research and development. It can be production, services, sustainment, or operational delivery.
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