It is assumed in this regulation that the transfers were not made for an adequate and full consideration in money or money's worth.
(a) Joint Bank Account. A transfer of a joint bank or similar account by the joint tenants to a third person constitutes a gift from each tenant to the extent of, or in proportion to, his contribution to the account. If a joint bank or similar account is created with community property each spouse contributes one-half of such property.
(b) Joint U. S. Savings Bond. A transfer of a joint United States savings bond by the joint tenants to a third person constitutes a gift from each tenant to the extent of, or in proportion to, his contribution for the bond. If a joint United States savings bond is purchased with community property each spouse contributes one-half of such property.
(c) Joint Tenancy Other Than Bank Account, U. S. Savings Bond, or Real Property Owned by Husband and Wife. A transfer of joint tenancy property, other than a joint bank or similar account, a joint United States savings bond, or real property owned by a husband and wife in a joint tenancy created on or after September 11, 1957, to a third person constitutes a gift of one-half of such property by each joint tenant. Note: For a transfer to a third person of real property owned by a husband and wife in a joint tenancy created on or after September 11, 1957, see Section 15104.50.
Cal. Code Regs. Tit. 18, § 15104.4
Note: Reference: Section 15104, Revenue and Taxation Code.