17 CFR 38.600 - Core Principle 11.
The board of trade shall establish and enforce:
(a) Rules and procedures for ensuring the financial integrity of transactions entered into on or through the facilities of the contract market (including the clearance and settlement of the transactions with a derivatives clearing organization); and
(b) Rules to ensure:
(1) The financial integrity of any:
(i) Futures commission merchant, and
(ii) Introducing broker; and
(2) The protection of customer funds.