Alternative trading system
Alternative trading system means any organization, association, person, group of persons, or system:
(1) That constitutes, maintains, or provides a market place or facilities for bringing together purchasers and sellers of securities or for otherwise performing with respect to securities the functions commonly performed by a stock exchange within the meaning of § 240.3b–16 of this chapter; and
(2) That does not:
(i) Set rules governing the conduct of subscribers other than the conduct of such subscribers' trading on such organization, association, person, group of persons, or system; or
(ii) Discipline subscribers other than by exclusion from trading.