31 CFR §359.28
Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗
The registration of a definitive Series I savings bond must include the TIN of the owner or first-named coowner. If the bond was purchased as a gift or award and the owner's TIN is not known, the TIN of the purchaser must be included in the registration of the bond.