(a) General
The gross estate shall include the value of an annuity or other payment receivable by any beneficiary by reason of surviving the decedent under any form of contract or agreement entered into after March 3, 1931 (other than as insurance under policies on the life of the decedent), if, under such contract or agreement, an annuity or other payment was payable to the decedent, or the decedent possessed the right to receive such annuity or payment, either alone or in conjunction with another for his life or for any period not ascertainable without reference to his death or for any period which does not in fact end before his death.
(b) Amount includible
Subsection (a) shall apply to only such part of the value of the annuity or other payment receivable under such contract or agreement as is proportionate to that part of the purchase price therefor contributed by the decedent. For purposes of this section, any contribution by the decedents employer or former employer to the purchase price of such contract or agreement (whether or not to an employees trust or fund forming part of a pension, annuity, retirement, bonus or profit sharing plan) shall be considered to be contributed by the decedent if made by reason of his employment.