Examples
Worked examples
- Is an instance
An NSF MRI award requires 30 percent cost share, to be met from institutional funds and quarterly reported.
- Is an instance
A Horizon Europe co-funded action mandates 50 percent national contribution as cost share.
Counter-examples
Looks similar, but isn't
- Not an instance
An institution's optional decision to contribute beyond what is required is voluntary cost share.
- Not an instance
A subaward partner's salary charge to the project is not cost share.
Editorial commentary
Mandatory cost share is the portion of project cost a sponsor requires the recipient (or a third party) to contribute as a condition of accepting the award, rather than a contribution the recipient chooses to offer. The requirement is set before the application stage — in the authorizing statute, the notice of funding opportunity, or the award’s general terms — and it is not something a proposal writer can decline to include once the programme requires it.
Where the requirement comes from
Mandatory cost-share percentages are program-specific, not universal. NSF’s Major Research Instrumentation programme has historically required a fixed institutional cost-share percentage; Horizon Europe co-funded partnerships require participating national funders to match the EU’s contribution at a set ratio. Because the figure varies by programme and can change between funding cycles, the applicable percentage should always be confirmed against the current notice of funding opportunity rather than assumed from a prior award.
What counts, under 2 CFR 200.306(b)
For US federal awards, contributed funds only qualify as cost share if they are verifiable in the recipient’s records, not already claimed against any other federal award, necessary and reasonable for the project’s objectives, allowable under the cost principles, not otherwise paid by the federal government (absent a specific statutory exception), and provided for in the approved budget when the agency requires that. A contribution that fails any one of these tests cannot be counted toward the commitment, even if it was genuinely spent on the project.
The risk of under-delivering
Because a cost-shared project’s funder share is frequently calculated as a percentage of total approved cost — sponsor funds plus the required match — falling short of a committed mandatory amount is a compliance shortfall against the award terms, not a private institutional matter, and a shortfall caught at closeout is far costlier to resolve than one corrected mid-project.
How it differs from voluntary cost share
Mandatory cost share is required regardless of what the applicant proposes; voluntary cost share is offered by the applicant to strengthen a proposal where the sponsor does not require it — federal policy under 2 CFR 200.306(a) actively discourages funders from soliciting the latter for merit review of federal research grants.
Also known as
Required cost share · Mandatory matching
Machine-readable encodings
Use in your systems
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