FAR 31.201-3—Determining reasonableness.
Plain-English Summary
FAR 31.201-3 explains how to decide whether a cost is reasonable for government contract cost allowability purposes. It covers the core reasonableness standard, the special scrutiny applied to firms or divisions without effective competitive restraints, the rule that no presumption of reasonableness attaches to contractor-incurred costs, and the burden-shifting rule that places proof on the contractor once a cost is challenged. It also identifies the main factors used to judge reasonableness: whether the cost is ordinary and necessary for the business or contract, whether it aligns with sound business practices and arm’s-length bargaining, whether it complies with Federal and State laws and regulations, whether it reflects the contractor’s responsibilities to the Government and other stakeholders, and whether it departs significantly from the contractor’s established practices. In practice, this section is a central audit and negotiation standard: it gives contracting officers a basis to question excessive, unusual, or poorly supported costs, and it tells contractors what evidence they need to keep to defend their pricing and incurred costs. The rule matters both before award, when evaluating proposed costs, and after award, when reviewing incurred costs, because reasonableness is a threshold requirement for allowability.
Key Rules
Prudent business standard
A cost is reasonable only if, in nature and amount, it would be incurred by a prudent person conducting competitive business. The test is not whether the contractor actually paid the cost, but whether the cost level makes business sense under competitive conditions.
Special scrutiny for weak competition
Costs from firms or divisions not subject to effective competitive restraints must be examined carefully. Where market discipline is limited, the Government should be more alert to inflated, unusual, or self-serving costs.
No presumption of reasonableness
Contractor-incurred costs are not automatically presumed reasonable. The contractor must be prepared to justify the cost with facts, documentation, and business rationale if the Government questions it.
Burden shifts after challenge
If the contracting officer or representative initially challenges a specific cost, the contractor bears the burden of proving the cost is reasonable. This makes contemporaneous support and clear explanations critical.
Ordinary and necessary costs
Reasonableness depends in part on whether the cost is generally recognized as ordinary and necessary for the contractor’s business or for contract performance. Unusual or unnecessary costs are harder to defend.
Business practice and legal compliance
The analysis includes whether the cost reflects sound business practices, arm’s-length bargaining, and compliance with Federal and State laws and regulations. A cost that results from poor controls, related-party favoritism, or legal noncompliance may be unreasonable.
Stakeholder responsibilities
The contractor’s duties to the Government, other customers, owners, employees, and the public are part of the reasonableness test. A cost that unfairly shifts risk or burden to the Government may be questioned.
Deviation from established practice
Significant departures from the contractor’s normal practices are a warning sign. If the contractor does something materially different from its usual approach, it should be able to explain why the change was justified.
Responsibilities
Contracting Officer
Evaluate questioned costs for reasonableness using the prudent-person standard and the factors in the rule. When facts suggest a cost may be excessive or unsupported, challenge it and require the contractor to justify the amount.
Contracting Officer’s Representative
Identify and elevate specific costs that appear unreasonable during technical, program, or invoice review. Provide the factual basis for the challenge so the contracting officer can assess allowability and support any disallowance.
Contractor
Maintain documentation and business rationale showing that costs are ordinary, necessary, and consistent with sound business practice. If a cost is challenged, prove that it is reasonable, including explaining any unusual amount, related-party transaction, or deviation from normal practice.
Agency
Apply consistent reasonableness standards in audits, cost reviews, and negotiations. Ensure personnel understand that contractor-incurred costs are not presumed reasonable and that challenged costs must be supported by evidence.
Practical Implications
Contractors should document the business case for significant costs before incurring them, especially for travel, consultants, executive compensation, subcontracting, and related-party charges.
A cost can be allowable in concept but still be disallowed if the amount is excessive or the contractor cannot show why it was prudent and necessary.
Related-party transactions, sole-source purchases, and costs from noncompetitive divisions are common flashpoints because market discipline may be weak or absent.
Significant changes from historical spending patterns often trigger questions, so contractors should be ready to explain spikes, one-time events, or policy changes.
Contracting officers should focus on facts, comparables, and business context rather than hindsight alone, but they may properly require the contractor to carry the burden once a specific cost is challenged.
Official Regulatory Text
(a) A cost is reasonable if, in its nature and amount, it does not exceed that which would be incurred by a prudent person in the conduct of competitive business. Reasonableness of specific costs must be examined with particular care in connection with firms or their separate divisions that may not be subject to effective competitive restraints. No presumption of reasonableness shall be attached to the incurrence of costs by a contractor. If an initial review of the facts results in a challenge of a specific cost by the contracting officer or the contracting officer’s representative, the burden of proof shall be upon the contractor to establish that such cost is reasonable. (b) What is reasonable depends upon a variety of considerations and circumstances, including- (1) Whether it is the type of cost generally recognized as ordinary and necessary for the conduct of the contractor’s business or the contract performance; (2) Generally accepted sound business practices, arm’s-length bargaining, and Federal and State laws and regulations; (3) The contractor’s responsibilities to the Government, other customers, the owners of the business, employees, and the public at large; and (4) Any significant deviations from the contractor’s established practices.