How do I know that my cost sharing costs are allowable?

As with costs directly charged to the sponsor, allowable cost sharing must be necessary and reasonable for the performance of the project objectives. As with direct charged expenses, cost shared expenses must be reasonable, allocable (i.e., directly benefit the specific project), and consistent with the terms of the award. Allowable cost sharing expenses must be expended (i.e., incurred) during the effective date of the award project. For details on eligibility criteria, see What Is Allowable/Eligible Cost Sharing.