Specified NTPC bonds: transferee must notify the issuer by registered post within prescribed period to secure proviso benefit. Central Government designates a private placement series of secured, redeemable, non convertible bonds issued by the National Thermal Power Corporation as specified for the proviso to the Income tax Act. The proviso's benefit is conditional: a transferee may claim the benefit only if the transferee informs the issuing corporation by registered post within sixty days of the transfer of the bonds.