For purposes of this part:

(a) Alternative trading system shall have the meaning set forth in section 1a(1) of the Act.

(b) Board of trade shall have the meaning set forth in section 1a(2) of the Act.

(c) Broad-based security index means a group or index of securities that does not constitute a narrow-based security index.

(d) Foreign board of trade means a board of trade located outside of the United States, its territories or possessions, whether incorporated or unincorporated, where foreign futures or foreign options are entered into.

(e) Narrow-based security index has the same meaning as in section 1a(35) of the Commodity Exchange Act.

(f) National securities association means a board of trade registered with the Securities and Exchange Commission pursuant to section 15A(a) of the Securities Exchange Act of 1934.

(g) National securities exchange means a board of trade registered with the Securities and Exchange Commission pursuant to section 6(a) of the Securities Exchange Act of 1934.

(h) Rule shall have the meaning set forth in Commission regulation 40.1.

(i) Security futures product shall have the meaning set forth in section 1a(32) of the Act.

(j) Opening price means the price at which a security opened for trading, or a price that fairly reflects the price at which a security opened for trading, during the regular trading session of the national securities exchange or national securities association that lists the security. If the security is not listed on a national securities exchange or a national securities association, then opening price shall mean the price at which a security opened for trading, or a price that fairly reflects the price at which a security opened for trading, on the primary market for the security.

(k) Regular trading session of a security means the normal hours for business of a national securities exchange or national securities association that lists the security.

(l) Regulatory halt means a delay, halt, or suspension in the trading of a security, that is instituted by the national securities exchange or national securities association that lists the security, as a result of:

(1) A determination that there are matters relating to the security or issuer that have not been adequately disclosed to the public, or that there are regulatory problems relating to the security which should be clarified before trading is permitted to continue; or

(2) The operation of circuit breaker procedures to halt or suspend trading in all equity securities trading on that national securities exchange or national securities association.

[66 FR 44511, Aug. 23, 2001, as amended at 66 FR 44965, Aug. 27, 2001; 67 FR 36761, May 24, 2002; 77 FR 66344, Nov. 2, 2012]