17 C.F.R. § 21.02
Upon special call by the Commission for information relating to futures or option positions held or introduced on the dates specified in the call, each futures commission merchant, clearing member, member of a reporting market, introducing broker, or foreign broker, and, in addition, for option information, each reporting market, shall furnish to the Commission the following information concerning accounts of traders owning or controlling such futures or option positions, except for accounts carried on a fully disclosed basis by another futures commission merchant or clearing member, as may be specified in the call:
(i) As applicable, the following identifying information:
(3) Whether any of the accounts in question are omnibus accounts and, if so, whether the originator of the omnibus account is another futures commission merchant, clearing member or foreign broker.
(Approved by the Office of Management and Budget under control number 3038-0017)
[46 FR 63036, Dec. 30, 1981, and 47 FR 57016, Dec. 22, 1982, as amended at 48 FR 35301, Aug. 3, 1983; 49 FR 1339, Jan. 11, 1984; 51 FR 4720, Feb. 7, 1986; 71 FR 37821, July 3, 2006; 72 FR 50211, Aug. 31, 2007; 74 FR 12192, Mar. 23, 2009]