17 CFR § 300.300 - Definitions.
For the purpose of these rules, adopted pursuant to section 8(e) of the Securities Investor Protection Act of 1970, as amended (hereinafter referred to as “the Act”):
(a) The term failed to receive shall mean a contractual commitment of the debtor made in the ordinary course of business to pay to another broker or dealer the contract price in cash upon receipt from such broker or dealer of securities purchased: Provided, That the respective obligations of the parties remained outstanding until the close of business on the filing date as defined in section 16(7) of the Act (hereinafter referred to as the “filing date”).
(b) The term failed to deliver shall mean a contractual commitment of the debtor, made in the ordinary course of business, to deliver securities to another broker or dealer against receipt from such broker or dealer of the contract price in cash: Provided, That the respective obligations of the parties remained outstanding until the close of business on the filing date.
(c) The term open contractual commitment shall mean a failed to receive or a failed to deliver which had a settlement date prior to the filing date and the respective obligations of the parties remained outstanding on the filing date or had a settlement date which occurs on or within three business days subsequent to the filing date: Provided, however, That the term “open contractual commitment” shall not include any contractual commitment for which the security which is the subject of the trade had not been issued by the issuer as of the trade date.
(d) The term customer shall mean a person (other than a broker or dealer) in whose behalf a broker or dealer has executed a transaction out of which arose an open contractual commitment with the debtor, but shall not include any person to the extent that such person at the filing date (1) had a claim for property which by contract, agreement of understanding, or by operation of law, was a part of the capital of the broker or dealer who executed such transaction or was subordinated to the claims of creditors of such broker or dealer, or (2) had a relationship with the debtor which is specified in section 9(a)(4) of the Act.