17 C.F.R. § 166.2
No futures commission merchant, retail foreign exchange dealer, introducing broker or any of their associated persons may directly or indirectly effect a transaction in a commodity interest for the account of any customer unless before the transaction the customer, or person designated by the customer to control the account:
(a) With respect to a commodity interest as defined in any paragraph of the commodity interest definition in § 1.3 of this chapter, specifically authorized the futures commission merchant, retail foreign exchange dealer, introducing broker or any of their associated persons to effect the transaction (a transaction is “specifically authorized” if the customer or person designated by the customer to control the account specifies—
[75 FR 55451, Sept. 10, 2010, as amended at 77 FR 66349, Nov. 2, 2012; 83 FR 7997, Feb. 23, 2018]