Two firms, fair prices, and a reasonable expectation
The rule of two is the test a contracting officer applies before deciding to reserve a requirement for small businesses. Stated plainly: if there is a reasonable expectation that at least two responsible small businesses will submit offers, and that award will be made at fair market prices, the requirement is set aside. It is a short sentence that drives a large share of federal buying, and most of the argument about it comes down to what counts as evidence.
That evidence is market research, and a surprising amount of it is written by industry. When a contracting officer posts a sources sought notice, the responses become part of the file that justifies the decision either way. A firm that responds well is not only signaling interest. It is supplying the proof the contracting officer needs to set the work aside.
This piece explains how the test works on each side of the simplified acquisition threshold, how the size line is drawn, how the market research is done, and what a response needs to contain to count.
What the rule says, below and above the threshold
The rule works differently depending on the size of the buy. The dividing line is the simplified acquisition threshold, which has been $350,000 since October 1, 2025.
| Estimated value | Starting point | The test | If the test is not met |
|---|---|---|---|
| Above the micro-purchase threshold, up to $350,000 | Automatically reserved for small businesses | Set aside unless there is no reasonable expectation of offers from two or more responsible small businesses competitive on market price, quality and delivery | The buy proceeds without the set-aside, and the reason is documented |
| Above $350,000 | No automatic reservation | Set aside when there is a reasonable expectation of offers from at least two responsible small businesses and award at fair market prices | The buy is competed without a small-business restriction, or another authorized approach is used |
Below the threshold, the default runs toward the set-aside, and the contracting officer needs a reason not to use it. Above the threshold, the contracting officer needs evidence to use it. In practice the evidence looks similar in both cases, but the burden points in opposite directions.
One more distinction is worth knowing. Below the threshold, if a set-aside draws only one acceptable offer from a responsible small business, the contracting officer ordinarily awards to that firm. If it draws none, the set-aside is withdrawn and the requirement is competed without the restriction. Orders under existing multiple-award contracts follow their own rules, where setting an order aside is generally at the contracting officer's discretion.
The same market research also tells the contracting officer whether a requirement could be reserved for one of the socioeconomic programs, such as 8(a), HUBZone, service-disabled veteran-owned or women-owned small businesses, each of which has its own eligibility rules.
"Reasonable expectation" is a judgment built on evidence
The test does not require certainty that two small businesses will bid. It requires a reasonable expectation, formed from market research and written down. That has two consequences that matter to both sides.
First, the contracting officer has real discretion. Reviewers generally defer to the contracting officer's judgment as long as the conclusion follows from the evidence and the research was reasonable for the size and complexity of the buy. A $90,000 analytics task does not need the research a $30 million program needs.
Second, the quality of the evidence matters more than its volume. Ten firms that self-identify as small and say "we can do this" are weaker evidence than three firms that show, specifically, that they have done comparable work at comparable scale and are small under the right size standard. The second kind of response lets a contracting officer write a determination that holds up.
The words "responsible" and "fair market prices" are part of the test, not decoration. A contracting officer is looking for firms that appear able to perform and that have priced or would price comparable work at levels consistent with the market. Evidence of similar prior contracts, at similar values, speaks to both.
Where the evidence comes from
Market research for a set-aside usually draws on three sources, in roughly this order.
Desk research in SAM.gov. The entity search shows registered firms by NAICS code, location and self-certified size status. Contract award history, searchable on USAspending.gov and in federal procurement data, shows which firms have actually won similar work, for which agencies, at what values. A contracting officer looking at a data analysis requirement can often find several small firms with directly comparable awards in an afternoon.
The SBA small business search. The Small Business Administration's search tool lets a contracting officer filter small businesses by NAICS code, keywords, certifications and capabilities narratives that the firms wrote themselves. A firm's profile there is often the first thing a contracting officer reads, which is a good reason to keep it specific and current.
A sources sought notice. When desk research is not conclusive, the contracting officer posts a notice on SAM.gov describing the requirement and asking interested firms to respond with their capabilities and size status. The notice is not a solicitation, and no award comes from it. Its whole purpose is to inform the acquisition strategy, including the set-aside decision.
Agencies often add industry days, one-on-one sessions or a draft statement of work for comment. Many also route the set-aside decision through a small business specialist in the contracting office, and the Small Business Administration has procurement center representatives who can review those decisions.
The NAICS code is a decision inside the decision
Every solicitation carries a NAICS code chosen by the contracting officer, and that code carries the size standard. A firm is small for that buy only if it is small under that code's standard. The same firm can be small under one code and large under another.
Size standards are set by the Small Business Administration. Most services codes use average annual receipts, averaged over the firm's recent completed fiscal years. Some codes, including several in scientific research and development, use average number of employees instead. Affiliates count toward size, so a firm under common control with another is measured together with it. Because the dollar and employee figures change through periodic adjustments, read the current table from the SBA rather than relying on a figure remembered from an older solicitation.
For a data or software requirement, the candidate codes often include custom programming, computer systems design, data processing, management consulting, and research and development codes. Each has a different standard. The contracting officer picks the code that best describes the principal purpose of the work, and that choice can change which firms count toward the rule of two.
Firms that think a code is wrong can say so in a sources sought response, with a short reason. Once a solicitation is issued, a NAICS designation can be appealed to the SBA's Office of Hearings and Appeals, but that window is short and the sources sought stage is the far better time to raise it.
From market research to set-aside decision
The sequence below is illustrative for a services requirement where desk research alone does not settle the question. Smaller buys compress it, and some offices run steps in parallel.
Market Research to Set-Aside Decision, Illustrative
Illustrative durations for a single services requirement. Office workload and review layers vary.
Step four is where responses win or lose their value. A contracting officer counting firms for the rule of two needs to confirm, for each one, that it is registered, small under the code, and plausibly able to do the work. A response that makes those three checks easy gets counted. A response that makes them hard often does not.
What a contracting officer needs from a response
A sources sought response is read by someone with a stack of them and a decision to document. It is not read like a proposal. It is read like evidence.
The contracting officer needs to answer three questions about your firm quickly: are you small under this code, can you do this specific work, and would you actually submit an offer. Everything in the response should help answer one of those questions, in the order the notice asked them.
Write it with that in mind. A sources sought response is not a sales document; it is evidence that a contracting officer will cite in writing. Specific prior work, with dates, scope and dollar range, is citable. "Extensive experience delivering innovative solutions" is not.
Why generic responses quietly fail
A generic capability statement attached to a one-line email technically counts as a response. It rarely counts toward the rule of two, because it does not show the firm can perform this particular requirement. When the contracting officer writes the determination, a response like that adds little weight, and a small field of generic responses can tip the decision away from a set-aside the firms wanted.
A checklist for a strong sources sought response
Use this before sending any response to a sources sought notice.
- Answer every question, in the order asked, with the notice's numbering
- Put identifiers at the top: legal name, UEI, CAGE code, point of contact with phone and email
- State your size under the notice's NAICS code, plus any socioeconomic certifications you actually hold
- Map your capability to this requirement, task by task, not to your general services
- Give two or three comparable examples: scope, customer type, period, approximate value, and what was delivered
- Describe how you would staff it, with the roles and the kind of people who would fill them
- Say plainly that you intend to submit an offer if the requirement is solicited as described
- Raise problems constructively: a NAICS code that does not fit, an unclear task, an unrealistic timeline
- Stay inside the page limit and send it to the named address before the deadline
- Confirm your SAM.gov registration is active and your profile lists the relevant NAICS code
The comments on the requirement are often the most useful part of a response, and firms leave them out for fear of seeming difficult. A clear note that the data access described would add two months, or that a task is unusually defined, helps the contracting officer write a better solicitation. Keep it brief and factual.
Mistakes on both sides of the table
Most set-aside problems are visible early, if anyone is looking.
Contracting side: a notice with no questions. A sources sought that says "send capability statements" gets capability statements, which are written for every buyer and fit none. Ask specific questions about the requirement, and the answers become usable evidence.
Contracting side: the wrong code. A data analysis requirement coded under an engineering or research code with a very different size standard changes who is small. Test the code against the principal purpose of the work.
Industry side: not responding at all. Firms that skip sources sought notices and wait for the solicitation sometimes discover the work was never set aside because too few small firms answered. Silence is counted too.
Industry side: claiming everything. A response that says the firm can do every task at any scale is weaker than one that is precise about what it has done. Contracting officers read hundreds of these and recognize inflation immediately.
Industry side: a profile that does not match. If the response claims expertise under a code the firm's SAM.gov profile does not list, the contracting officer notices the mismatch during verification. Keep the registration and the response consistent.
Frequently asked questions
It is the test for reserving a requirement for small businesses: a reasonable expectation that offers will come from at least two responsible small businesses, and that award will be made at fair market prices. Below the simplified acquisition threshold, buys above the micro-purchase threshold are reserved for small businesses unless that expectation is absent. Above it, the contracting officer sets the buy aside when the expectation is present.
No. A sources sought notice is market research. It helps the contracting officer decide the acquisition strategy, including whether to set the requirement aside, and no contract is awarded from the responses. A solicitation, if one follows, is a separate notice that firms must respond to.
Against the size standard for the NAICS code in the solicitation. Most services codes use average annual receipts over recent completed fiscal years; some use average employees. Affiliates count. A firm can be small under one code and not under another, so check the standard for the specific code in each notice.
Below the simplified acquisition threshold, if only one acceptable offer from a responsible small business is received, the contracting officer ordinarily awards to that firm. If no acceptable offers come in, the set-aside is withdrawn and the requirement is competed without the restriction.