The registration of a definitive Series EE savings bond must include the TIN of the owner or first-named coowner. The TIN of the second-named coowner or beneficiary is not required but its inclusion is desirable. 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.
31 C.F.R. §351.43