29 C.F.R. § 1470.50 – Closeout.

(a) General. The Federal agency will close out the award when it determines that all applicable administrative actions and all required work of the grant has been completed.
(b) Reports. Within 90 days after the expiration or termination of the grant, the grantee must submit all financial, performance, and other reports required as a condition of the grant. Upon request by the grantee, Federal agencies may extend this timeframe. These may include but are not limited to:
1. (1) Final performance or progress report.
2. (2) Financial Status Report (SF-269) or Outlay Report and Request for Reimbursement for Construction Programs (SF-271) (as applicable).
3. (3) Final request for payment (SF-270) (if applicable).
4. (4) Invention disclosure (if applicable).
5. (5) Federally-owned property report:
  In accordance with § 1470.32(f), a grantee must submit an inventory of all federally owned property (as distinct from property acquired with grant funds) for which it is accountable and request disposition instructions from the Federal agency of property no longer needed.
(c) Cost adjustment. The Federal agency will, within 90 days after receipt of reports in paragraph (b) of this section, make upward or downward adjustments to the allowable costs.
(d) Cash adjustments.
1. (1) The Federal agency will make prompt payment to the grantee for allowable reimbursable costs.
2. (2) The grantee must immediately refund to the Federal agency any balance of unobligated (unencumbered) cash advanced that is not authorized to be retained for use on other grants.