Treas. Reg. § 1.72-10

(a) If a contract to which section 72 applies, or any interest therein, is transferred for a valuable consideration, by assignment or otherwise, only the actual value of the consideration given for such transfer and the amount of premiums or other consideration subsequently paid by the transferee shall be included in the transferee's aggregate of premiums or other consideration paid. In accordance with the provisions of section 72(g)(3) and paragraph (b) of § 1.72-4, an annuity starting date shall be determined for the transferee without regard to the annuity starting date, if any, of the transferor. In determining the transferee's investment in the contract, the aggregate amount of premiums or other consideration paid shall be reduced by all amounts received by the transferee before the receipt of an amount as an annuity or before the annuity starting date, whichever is the later, to the extent that such amounts were excludable from his gross income under the applicable income tax law at the time of receipt. For the treatment of amounts received by the transferee subsequent to both the annuity starting date and the date of receipt of a payment as an annuity, but not received as annuity payments, see § 1.72-11. For a limitation on adjustments to the basis of annuity contracts sold, see section 1021.

(b) In the case of a transfer of such a contract without valuable consideration, the annuity starting date and the expected return under the contract shall be determined as though no such transfer had taken place. See paragraph (b) of § 1.72-4. The transferee shall include the aggregate of premiums or other consideration paid or deemed to have been paid by his transferor in the aggregate of premiums or other consideration as though paid by him. In determining the transferee's investment in the contract, the transferee's aggregate amount of premiums or other consideration paid (as so found) shall be reduced by all amounts either received or deemed to have been received by himself or his transferor before the annuity starting date, or before the date on which an amount is first received as an annuity, whichever is the later, to the extent that such amounts were excludable from the gross income of the actual recipient under the applicable income tax law at the time of receipt. For treatment of amounts received subsequent to both the above dates by such transferee, but not received as annuity payments, see § 1.72-11.