For the first time in history on Monday Rule 48 was invoked on S&P 500 Futures.
Rule 48 allows designated market makers on the NYSE to refrain from disseminating price indications ahead of the opening bell. The procedure makes it easier and faster to open stocks on days when trading could be perilous.
The so-called “flash-crash” of 2010 prompted a Rule 48 switch from the Dow to the S&P 500.
“It was set up for situations like this,” said Art Hogan, chief market strategist at Wunderich Securities, told CNBC.