Another tech glitch, this time with the NYSE's Securities Information Processor (SIP), which consolidates quote and trade data for NYSE-listed stocks.
According to a statement from the NYSE, the first glitch occurred at 1:07 PM ET. The SIP went down, which means that the NYSE and the other exchanges---the NASDAQ and BATS--could not exchange information on bids and offers. Simply put, they couldn't talk to each other.
Since options price off of stocks, the glitch also affected trading in options; the Options Price Reporting Authority (OPRA), serves the same function as the SIP for options, consolidating last sale information and option quotes.
At 1:34 PM, the NYSE switched to a backup system in Chicago. Normal processing resumed for quotes at that time, then at 1:37 PM normal processing occurred for trades that had been executed, then at 1:41 PM for options pricing and quoting.
NASDAQ and BATS was able to connect to the backup system shortly thereafter. No word from NYSE as to what caused the glitch, but they are planning to restore normal operation from the main data center tomorrow.