17 CFR § 1.57 - Operations and activities of introducing brokers.
(a) Each introducing broker must:
(1) Open and carry each customer's account with a carrying futures commission merchant on a fully-disclosed basis: Provided, however, That an introducing broker which has entered into a guarantee agreement with a futures commission merchant in accordance with the provisions of § 1.10(j) must open and carry such customer's account with such guarantor futures commission merchant on a fully-disclosed basis; and
(i) A carrying futures commission merchant; or
(ii) A floor broker, if the introducing broker identifies its carrying futures commission merchant and that carrying futures commission merchant is also the clearing member with respect to the customer's order.
(c) An introducing broker may not accept any money, securities or property (or extend credit in lieu thereof) to margin, guarantee or secure any trades or contracts of customers, or any money, securities or property accruing as a result of such trades or contracts: Provided, however, That an introducing broker may deposit a check in a qualifying account or forward a check drawn by a customer if:
(1) The futures commission merchant carrying the customer's account authorizes the introducing broker, in writing, to receive a check in the name of the futures commission merchant, and the introducing broker retains such written authorization in its files in accordance with § 1.31;
(3) The check is deposited by the introducing broker, on the same day upon which it is received, in a bank or trust company located in the United States in a qualifying account, or the check is mailed or otherwise transmitted by the introducing broker to the futures commission merchant on the same day upon which it is received;
(4) For purposes of this paragraph (c), a qualifying account shall be deemed to be an account:
(ii) For which the bank or trust company restricts withdrawals to withdrawals by the carrying futures commission merchant;
(iii) For which the bank or trust company prohibits the introducing broker or anyone acting upon its behalf from withdrawing funds; and
(iv) For which the bank or trust company provides the futures commission merchant carrying the customer's account with a written acknowledgment, which the futures commission merchant must retain in its files in accordance with § 1.31, that it was informed that the funds deposited therein are those of customers and are being held in accordance with the provisions of the Act and the regulations in this chapter.