The new procedures would eliminate “Rule 48,” which allows market makers to delay opening a stock when markets are volatile.
Under the changes, parameters governing NYSE and NYSE MKT pre-open price indications as well as those governing automated openings would be simplified and would adjust for market volatility, the NYSE said on Thursday.
All indications will now be published to both proprietary and other feeds under all market conditions, it said.
The U.S. Securities and Exchange Commission had approved the changes in early July.
The NYSE, a unit of Intercontinental Exchange Inc (ICE.N), had asked for the new rules after disorderly trading on Aug. 24, 2015, when there was a record intraday drop in the Dow Jones industrial average .DJI.
Unlike other exchanges, which are nearly fully automated, at the NYSE people on the trading floor open the stocks, a process the exchange says gives it greater stability because people can intervene in ways that trading algorithms cannot.
