17 CFR § 1.58 - Gross collection of exchange-set margins.
(a) Each futures commission merchant which carries a commodity futures or commodity option position for another futures commission merchant or for a foreign broker on an omnibus basis must collect, and each futures commission merchant and foreign broker for which an omnibus account is being carried must deposit, initial and maintenance margin on each position reported in accordance with § 17.04 of this chapter at a level no less than that established for customer accounts by the rules of the applicable contract market.
(b) If the futures commission merchant which carries a commodity futures or commodity option position for another futures commission merchant or for a foreign broker on an omnibus basis allows a position to be margined as a spread position or as a hedged position in accordance with the rules of the applicable contract market, the carrying futures commission merchant must obtain and retain a written representation from the futures commission merchant or from the foreign broker for which the omnibus account is being carried that each such position is entitled to be so margined.