A trader signals an offer in the Standard & Poors 500 stock index futures pit at the CME Group December 14, 2010 in Chicago City.
Scott Olson | Getty Images News | Getty Images
The data feeds for key market averages had an issue on Thursday that caused the calculations for the S&P 500 and the Dow Jones Industrial Average to halt. Trading continues normally and individual stock prices did not appear impacted.
The CME Group confirmed to CNBC that there were issues affecting at least the calculations of those two indexes on Thursday for its customers. It appears the last calculation for the Dow and S&P 500 happened at 10:41 a.m. ET.
Issues with data feeds for the indexes do not necessarily affect trading. Futures markets for the S&P 500 and the Dow appeared to be operating normally.
The SPDR S&P 500 ETF Trust (SPY), a common vehicle for investors to make broad market bets, also appeared to be actively trading. It was last down 0.4% on the day.
