31 CFR §353.29

1. (a)General. The Bureau of the Fiscal Service will adjudicate claims for lost, stolen or destroyed bonds on the basis of records created and regularly maintained in the ordinary course of business.
2. (b)Claims filed 10 years after payment. A bond for which no claim has been filed within 10 years of the recorded date of redemption will be presumed to have been properly paid. If a claim is subsequently filed, a photographic copy of the bond will not be available to support the disallowance.
3. (c)Claims filed six years after final maturity. No claim filed six years or more after the final maturity of a savings bond will be entertained unless the claimant supplies the serial number of the bond.