the completion of the transaction
The term the completion of the transaction means:
(3) In the case of a customer who sells a security through or to a broker, dealer or municipal securities dealer except as provided in paragraph (b)(4) of this section, if the security is not in the custody of the broker, dealer or municipal securities dealer at the time of sale, the time when the security is delivered to the broker, dealer or municipal securities dealer, and if the security is in the custody of the broker, dealer or municipal securities dealer at the time of sale, the time when the broker, dealer or municipal securities dealer transfers the security from the account of such customer;