Rule 48 in trading
This followed a dramatic drop in pre-market open futures, with the Dow Jones Industrial Average futures falling more than points.

It's only used in the event that extremely high market volatility is likely to have a floor-wide impact on the ability of designated market makers DMMs to disseminate price indications before the bell.
Rule 48 speeds up the opening by suspending the requirement that stock prices be announced at the market open.

Those prices have to be approved by stock market floor rule 48 in trading before trading actually begins. Without that approval, stock trading can begin sooner.

To invoke Rule 48, an exchange must determine that certain conditions exist that would cause market disruptions. Those conditions include: volatility during 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; government announcements.

Rule 48 was approved by the Securities and Exchange Commission on Dec. Rule 48 was invoked a few times in recent years, including on Jan.

Inthe stock markets were subject to great volatility over fears of a global recession and inthe European debt crisis caused panic buying and selling. The rule was also invoked during the August-September time frame, when European debt crisis fears again roiled the markets, and in earlywhen massive snowstorms swept across the U.