The closeout or completion of an open contractual commitment meeting the requirements of § 300.301 shall be effected only:

By the buy-in or sell-out of the commitment by the other broker or dealer in accordance with the usual trade practices initiated by the other broker or dealer within or promptly upon the expiration of a period of 30 calendar days after settlement date; or

At the option of the trustee by the delivery of securities against receipt of the contract price or payment of the contract price against the receipt of the securities at any time within 30 calendar days after settlement date unless the commitment previously has been bought-in or sold-out in accordance with paragraph (a)(1) of this section; or

In the event of the refusal of the other broker or dealer to accept completion of an open contractual commitment in accordance with paragraph (a)(2) of this section, or the failure of the other broker or dealer to promptly buy-in or sell-out a commitment in accordance with paragraph (a)(1) of this section, or in the event of the failure of the other broker or dealer to provide the trustee with appropriate documentation as required by § 300.303, by delivery of securities against receipt of the contract price or payment of the contract price against receipt of securities, or the buy-in or sell-out of the commitment or cancellation of the commitment or otherwise, as may be appropriate, as the trustee in his discretion will most benefit the estate of the debtor.

In the event of a close-out of an open contractual commitment pursuant to paragraph (a)(1) of this section, the money differences resulting from such close-out shall be payable by the other broker or dealer to the trustee or by the trustee to the other broker or dealer, whichever would be entitled to receive such difference under the usual trade practices: Provided, however, (1) That prior to the payment of any such money difference by the trustee to such other broker or dealer with respect to transactions executed by such other broker or dealer for any separate customer account, all open contractual commitments with respect to such account which meet the requirements of § 300.301 must have been completed by delivery of securities against receipt of the contract price or by payment of the contract price against receipt of the securities in conformity with paragraph (a)(2) of this section, or by buy-in or sell-out in conformity with paragraph (a)(1) of this section, and (2) that the net amount so payable by the trustee to the other broker or dealer shall not exceed $40,000 with respect to any separate customer account.