31 C.F.R. § 355.4 Is there a time limit on cashing a fiscal agency check?
Title 31 - Money and Finance: Treasury
A payor Reserve Bank may refuse to pay a fiscal agency check presented more than six (6) months after the issue date of the check. If the check is not presented within this time, you must follow the procedures in §355.10.
Title 31: Money and Finance: Treasury
PART 355—REGULATIONS GOVERNING FISCAL AGENCY CHECKS
§ 355.4 Is there a time limit on cashing a fiscal agency check?

