US STOCKS SNAPSHOT-NYSE sets up for volatile open21 minutes ago by Thomson Reuters NEW YORK, Sept 6 (Reuters) - The New York Stock Exchange and NYSE Amex Cash Markets invoked a rule to smooth trading at the market open on Tuesday as futures pointed to a sharp drop in the major indexes.
Rule 48 allows the exchange to suspend price indications that help determine the floor price at the open during regular sessions. Bypassing the requirement helps speed the beginning of trading.
Among the triggers for invoking the rule are "substantial activity in the futures market before the open," according to the exchange's website.
U.S. stock index futures pointed to a sharply lower open, tracking European equities on renewed fears the euro zone's sovereign debt crisis was worsening.
S&P 500 futures <SPc1> fell 27.1 points and were below fair value, a formula that evaluates pricing by taking into account interest rates, dividends and time to expiration of the contract. Dow Jones industrial average futures <DJc1> lost 226 points and Nasdaq 100 futures <NDc1> dropped 38.25 points. (Reporting by Rodrigo Campos; editing by Jeffrey Benkoe)

oh yea, good old Rule 48, i've heard of that..

like never!!!!!!!

Interestingly enough, there is no Rule 48 on the NYSE website:

NYSE Rules

But a search did turn it up:

NYSE Rules

Quoting 

Rule 48. Exemptive Relief — Extreme Market Volatility Condition (a) In the event that extremely high market volatility is likely to have a Floor-wide impact on the ability of DMMs to arrange for the fair and orderly opening, reopening following a market-wide halt of trading at the Exchange, or closing of trading at the Exchange and that absent relief, the operation of the Exchange is likely to be impaired, a qualified Exchange officer may declare an extreme market volatility condition with respect to trading on or through the facilities of the Exchange. (b) In the event that an extreme market volatility condition is declared with respect to trading on or through the facilities of the Exchange, a qualified Exchange officer shall be empowered to temporarily suspend at the opening of trading or reopening of trading following a market-wide trading halt: (i) the need for prior Floor Official or prior NYSE Floor operations approval to open or reopen a security at the Exchange (Rules 123D(1) and 79A.30); and/or (ii) applicable requirements to make pre-opening indications in a security (Rules 15 and 123D(1)). (c) A suspension under section (b) of this Rule is subject to the following provisions: (1) (A) Before declaring an extreme market volatility condition, the qualified Exchange officer shall consider the facts and circumstances that are likely to have Floor-wide impact for a particular trading session, including volatility in the previous day's trading session, trading in foreign markets before the open, substantial activity in the futures market before the open, the volume of pre-opening indications of interest, evidence of pre-opening significant order imbalances across the market, government announcements, news and corporate events, and such other market conditions that could impact Floor-wide trading conditions. (B) Such review shall be undertaken in consultation with relevant officers of NYSE Market and NYSE Regulation, as appropriate. Following the review, the qualified Exchange officer or his or her designee shall document the basis for declaring an extreme market volatility condition. (2) The qualified Exchange officer will, as promptly as practicable in the circumstances, inform the Securities and Exchange Commission staff that an extreme market volatility condition has been declared, the basis for such declaration, and what relief has been granted. (3) An extreme market volatility condition may only be declared before the scheduled opening or reopening following a market-wide halt of securities at the Exchange. (4) A declaration of an extreme market volatility condition shall be in effect only for the particular opening or reopening for the trading session on the particular day that the extreme market volatility condition is determined to exist. The Exchange may declare a separate extreme market volatility condition on subsequent days subject to sections (b)(1) through (b)(3) above. (5) A declaration of extreme market volatility shall not relieve DMMs from the obligation to make pre-opening indications in situations where the opening of a security is delayed for reasons unrelated to the extreme market volatility condition. (d) For purposes of this Rule, a "qualified Exchange officer" means the Chief Executive Officer of NYSE Euronext, Inc., or his or her designee, or the Chief Executive Officer of NYSE Regulation, Inc., or his or her designee. Adopted: December 6, 2007 (NYSE-2007-111). Amended: October 7, 2008 (NYSE-2008-102); October 24, 2008 (NYSE-2008-46); December 10, 2008 (NYSE-2008-127); December 29, 2008 (NYSE-2008-139); March 31, 2009 (NYSE-2009-35); April 13. 2009 (NYSE-2009-18).

Mike