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An appropriation account expires “[a]t midnight on the last day of an appropriation’s period of availability” and is “no longer available for incurring new obligations.”**

Spending appropriated funding funds beyond its their period of availability is a violation of the ADA violates the Anti-Deficiency Act (ADA) and is monitored closely by the Office of Management and Budget (OMB).

Within the context of federal financial assistance awards, an appropriation is properly spent at spent—and, thus, will not expire—at the time of the award's obligation:

From the Red Book (p.10-39):

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Appropriated funds which remain unobligated after this the period of availability date are considered expired. Deobligated funds after their period of availability date are also considered expired. How expired funds are recovered depends on the bill that authorized them. 

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