31 CFR § 363.10 - What is a TreasuryDirect ® account?
(1) Individual. A primary account for an individual may contain Treasury securities purchased initially as book-entry securities that are your personal holdings registered in single owner, owner with beneficiary, and primary owner with secondary owner forms of registration; gifts of savings bonds that have not yet been delivered; and converted savings bonds that were transferred from the conversion linked account.
(2) Entities. A primary account for an entity may contain Treasury securities purchased initially as book-entry securities registered in the name of the entity and converted savings bonds in the name of the entity that were transferred from the conversion linked account.
(b) Linked account. A linked account is an account that is a separate account from your primary account, but that is connected to your primary account. You use your primary account as a portal to open and access the linked account. Linked accounts include the following:
(1) Custom account. A custom account is an account that is linked to your primary account. You use your primary account as the portal to open and access your custom account. You may informally designate a purpose for the custom account, for example, “vacation fund”, or “Johnny's college fund”. However, the designation as to purpose has no legal effect; the registration of the securities held in the custom account determines ownership (Annual purchase limitations include securities held in custom accounts). You, as an individual owner, may use your custom account to buy, redeem, and transfer securities that you own in single owner, owner with beneficiary, and primary owner with secondary owner forms of registration. An individual owner may also buy and deliver gift savings bonds from the custom account. An entity account manager, acting on behalf of an entity, may use the entity's custom account to buy, redeem, and transfer securities registered in the entity form of registration.
(2) Minor account. A minor account is an account established by an individual custodian for an individual who has not yet reached the age of 18 years. We do not permit an entity to open a minor account. A minor account is linked to the custodian's primary account. The minor is the owner of the securities, but the custodian controls the account on behalf of the minor. (See § 363.27 for more information about minor accounts.)
(3) Conversion account means a linked account in TreasuryDirect that contains only savings bonds that have been converted from definitive bonds to book-entry bonds.
(c) Closing an account. If a TreasuryDirect primary account and all associated linked accounts have had no holdings and no activity for a period of two years, we reserve the right to close the account, along with all linked accounts.