What Is Cost Sharing? Mandatory vs. Voluntary Under 2 CFR 200.306

Cost sharing (also called matching) is the portion of a sponsored project’s total cost that a recipient — or a third party on the recipient’s behalf — funds from non-federal sources rather than billing to the federal award. When an institution commits cost sharing, it is legally promising the sponsor that specific resources, beyond what the award itself pays for, will support the project. That promise becomes an auditable obligation, not a courtesy: once cost sharing is committed in a proposal or notice of award, the institution must actually incur it, document it, and be able to prove it during an audit — exactly as if it were federal grant expenditure.

For US federal awards, cost sharing is governed by the OMB Uniform Guidance at 2 CFR §200.306, “Cost sharing or matching”. This guide explains what counts as cost sharing under that regulation, why mandatory and voluntary committed cost sharing are treated so differently, how in-kind contributions are valued, and why cost sharing is one of the most frequently cited findings in federal grant audits.

Mandatory vs. voluntary committed cost sharing

Research administrators generally sort cost sharing into three practical categories, though only two of them create a binding obligation:

• Mandatory cost sharing is required by the terms of the specific funding opportunity or statute — the sponsor’s notice of funding opportunity (NOFO) states that applicants must contribute a defined share (e.g., 1:1 matching, or a stated percentage of total project cost) as a condition of eligibility. See Cost share (mandatory) for the operational definition and worked examples. Many training and infrastructure programs (and non-research grant programs generally) carry mandatory match requirements; NIH and NSF research grants rarely do, by policy.
• Voluntary committed cost sharing is not required by the sponsor but is offered anyway — typically written into the proposal budget or narrative (e.g., a PI pledging a percentage of committed effort beyond what the award compensates). Once written into an accepted proposal, it converts from voluntary to a binding, auditable commitment identical in enforcement terms to mandatory cost sharing. See Cost share (voluntary).
• Voluntary uncommitted cost sharing is effort or resources an institution contributes without ever having promised it in a proposal or award document — for example, unplanned extra faculty time on a project. Because it was never committed, it creates no compliance obligation and, per 2 CFR 200.306 and related OMB guidance, is explicitly excluded from an institution’s effort-reporting and cost-accounting base. This category is a common source of confusion: institutions sometimes over-document voluntary uncommitted effort out of caution, when the regulation does not require it to be tracked as cost sharing at all.

2 CFR 200.306 places a deliberate thumb on the scale against voluntary committed cost sharing for federal research grants specifically: federal agencies may not use voluntary committed cost sharing as a factor in the merit review of a research grant application unless a federal statute or agency regulation authorizes it and the funding notice says so explicitly. The policy rationale, carried over from the Uniform Guidance’s predecessor circulars, is to stop cost sharing from becoming an unofficial, unlevel competitive factor between well-resourced and under-resourced applicant institutions. Once cost sharing IS properly committed — mandatory or voluntary — the sponsor must accept any cash or in-kind contribution that meets the verifiability conditions below; there is no discretion to reject a properly documented match after the fact.

In-kind vs. cash matching

Cost sharing can take two basic forms, and most real awards use a mix of both:

• Cash matching is a direct, budgeted expenditure of the institution’s own (non-federal) funds toward allowable project costs — for example, an institution paying a portion of a piece of equipment’s purchase price from discretionary funds, or a state or foundation grant paying a defined share of project costs alongside the federal award. See Match funding.
• In-kind (non-cash) contributions are goods, services, or use of property provided instead of cash — donated equipment, third-party volunteer professional services, use of space, or a subrecipient’s own committed effort. 2 CFR 200.306 sets specific valuation ceilings for each: donated equipment and real property may not be valued above fair market value at the time of donation (established by independent appraisal for land/buildings); donated space is valued at fair rental value of comparable space; donated professional/technical services are valued at rates consistent with what the institution pays for similar work, or prevailing market rates if the institution has no comparable position. Loaned (not donated) equipment is valued at fair rental value, not purchase price.

A related and frequently overlooked category is unrecovered indirect costs — the difference between the indirect (F&A) costs an institution is entitled to recover under its negotiated rate and what it actually charges the award (for example, when a sponsor caps indirect cost recovery below the institution’s federally negotiated rate). Under 2 CFR 200.306, an institution may count that unrecovered amount as cost sharing, but only with the prior approval of the federal awarding agency or pass-through entity — it is not an automatic entitlement. See Indirect Cost Rate (F&A Rate) and Indirect costs (overheads) for how negotiated rates work.

The seven verifiability conditions

Whatever form it takes, 2 CFR 200.306 requires that any cash or in-kind contribution counted toward cost sharing must, at minimum:

1. Be verifiable from the recipient’s or subrecipient’s records;
2. Not be included as a contribution for any other federally assisted project or program (no double-counting the same dollar or hour across two awards);
3. Be necessary and reasonable for accomplishing the project’s objectives;
4. Be allowable under the applicable cost principles (2 CFR Part 200, Subpart E);
5. Not be paid by another federal award, except where a federal statute specifically authorizes federal funds to count as matching for another federal program;
6. Be provided for in the approved budget when required by the federal awarding agency; and
7. Conform to all other applicable provisions of 2 CFR Part 200.

Contributions from third parties (a subawardee, a community partner, a donor) count on exactly the same terms as the recipient’s own contributions, provided they meet these seven conditions and are properly documented in the recipient’s or subrecipient’s records — not merely asserted.

Why it matters for compliance and audit

Cost sharing converts a proposal-stage promise into an ongoing legal and financial obligation with the same enforcement weight as spending the federal award itself. That has several concrete downstream effects research administrators plan for:

• It must be tracked in the institution’s official accounting system, not in a side spreadsheet — auditors expect cost sharing to be traceable to the general ledger with the same rigor as direct federal expenditure, since 2 CFR 200.306 treats it as part of the total project cost base.
• It is a routine focus of the Single Audit. Institutions expending $1,000,000 or more in federal awards in a fiscal year are subject to a Single Audit under 2 CFR Part 200, Subpart F, and cost sharing/matching is explicitly one of the compliance requirements auditors test (per the OMB Compliance Supplement). Under- or over-reported cost sharing, or cost sharing that fails the verifiability conditions above, is a recurring finding type. See Single Audit (US).
• Shortfalls carry real consequences. If a recipient commits cost sharing and then fails to actually incur it, the federal awarding agency can proportionally reduce the federal share of the award, require the institution to make up the shortfall from other non-federal sources, or — in an egregious or knowing case — treat the discrepancy as a false statement in a funding request, which can implicate the False Claims Act.
• It interacts directly with effort reporting. Committed voluntary cost sharing in the form of PI or key-personnel effort must be certified through the institution’s effort-reporting system, exactly like federally compensated effort, because it is now a committed obligation rather than a courtesy. Uncertified or inconsistently certified cost-shared effort is one of the most common audit findings tied to this section. See Effort Reporting Methodologies.
• It should be scoped carefully at the proposal stage. Because voluntary committed cost sharing becomes a binding obligation the moment a proposal is funded, many institutions have internal policies discouraging or requiring pre-approval for any voluntary cost-sharing commitment in a proposal budget, specifically to avoid downstream audit exposure the sponsor didn’t even require.

Cost sharing vs. related terms

Cost sharing is sometimes conflated with adjacent budget concepts that are actually distinct:

• Cost sharing vs. direct charging: direct charging is about which costs are billed straight to a specific award as a direct cost of that project; cost sharing is about which portion of total project cost is NOT billed to the federal award at all. See Direct charging.
• Cost sharing vs. bridge funding: bridge funding covers a gap between two awards (e.g., while a competing renewal is pending); it is not a matching commitment tied to a specific award’s terms. See Bridge funding.
• Cost sharing vs. subrecipient cost share: when a subaward carries its own cost-sharing commitment, the pass-through entity is responsible for ensuring the subrecipient’s cost sharing is documented and verifiable under the same 2 CFR 200.306 conditions — part of the broader subrecipient monitoring obligation.

Frequently asked questions

Is cost sharing required on NIH or NSF research grants?

Generally no. Both agencies, consistent with 2 CFR 200.306’s restriction on using voluntary committed cost sharing in merit review, do not require cost sharing on most research grant mechanisms unless a specific NOFO states otherwise (this is more common for training, infrastructure, or center-type awards than for standard research project grants). Always check the specific funding opportunity rather than assuming a blanket agency policy.

Does cost sharing have to be a specific percentage of the award?

Only if the funding opportunity or statute specifies one. When mandatory cost sharing is required, the NOFO or program statute states the required ratio or percentage; there is no single government-wide default ratio under 2 CFR 200.306 itself.

Can indirect (F&A) costs count toward a cost-sharing requirement?

Unrecovered indirect costs can count, but only with the prior written approval of the federal awarding agency or pass-through entity — it is not automatic, and institutions should confirm this in writing before assuming it will satisfy a match requirement.

What happens if committed cost sharing isn’t actually met?

The federal awarding agency can require the shortfall to be made up from other non-federal sources, reduce the federal share of the award proportionally, or treat it as a compliance finding in a Single Audit — and, in serious cases, as a false statement issue. This is why cost-sharing commitments should be scoped conservatively at the proposal stage.

This guide covers US federal cost-sharing requirements under 2 CFR 200.306. Non-US funders (e.g., UKRI, Horizon Europe, Tri-Agency in Canada) use analogous but not identical matching-fund concepts under their own financial rules — always confirm the governing rules of the specific funder and award.