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.