(1) In the case of a customer who purchases a security through or from a broker, dealer or municipal securities dealer, except as provided in paragraph (b)(2) of this section, the time when such customer pays the broker, dealer or municipal securities dealer any part of the purchase price, or, if payment is effected by a bookkeeping entry, the time when such bookkeeping entry is made by the broker, dealer or municipal securities dealer for any part of the purchase price;

(2) In the case of a customer who purchases a security through or from a broker, dealer or municipal securities dealer and who makes payment therefor prior to the time when payment is requested or notification is given that payment is due, the time when such broker, dealer or municipal securities dealer delivers the security to or into the account of such customer;

(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;

(4) In the case of a customer who sells a security through or to a broker, dealer or municipal securities dealer and who delivers such security to such broker, dealer or municipal securities dealer prior to the time when delivery is requested or notification is given that delivery is due, the time when such broker, dealer or municipal securities dealer makes payment to or into the account of such customer.