17 C.F.R. § 240.11a1-1(T)
(a) A transaction effected on a national securities exchange for the account of a member which meets the requirements of section 11(a)(1)(G)(i) of the Act shall be deemed, in accordance with the requirements of section 11(a)(1)(G)(ii), to be not inconsistent with the maintenance of fair and orderly markets and to yield priority, parity, and precedence in execution to orders for the account of persons who are not members or associated with members of the exchange if such transaction is effected in compliance with each of the following requirements:
(b) A member shall be deemed to meet the requirements of section 11(a)(1)(G)(i) of the Act if during its preceding fiscal year more than 50 percent of its gross revenues was derived from one or more of the sources specified in that section. In addition to any revenue which independently meets the requirements of section 11(a)(1)(G)(i), revenue derived from any transaction specified in paragraph (A), (B), or (D) of section 11(a)(1) of the Act or specified in 17 CFR 240.11a1-4(T) shall be deemed to be revenue derived from one or more of the sources specified in section 11(a)(1)(G)(i). A member may rely on a list of members which are stated to meet the requirements of section 11(a)(1)(G)(i) if such list is prepared, and updated at least annually, by the exchange. In preparing any such list, an exchange may rely on a report which sets forth a statement of gross revenues of a member if covered by a report of independent accountants for such member to the effect that such report has been prepared in accordance with generally accepted accounting principles.
(Secs. 2, 3, 6, 11, 11A, and 23, 89 Stat. 97, 104, 110, 111, 156 (15 U.S.C. 78b, 78c, 78f, 78k, 78k-1, 78w); secs. 2, 3, 11, 23, 48 Stat. 881, 882, 885, 891, 901, as amended)
[43 FR 11553, Mar. 17, 1978, as amended at 43 FR 18562, May 1, 1978; 44 FR 6093, Jan. 31, 1979]