the new york stock exchange on tuesday said it was still looking into the technical issue that led to a large number of trading halts shortly after the opening bell the exchange continues to investigate issues with todays opening auction in a subset of symbols opening auctions did not occur the nyse said in a technical update the opening auction occurs at 930 am et and produces the opening price for individual stocks dozens of stocks were briefly halted after the opening bell for volatility according to the nyse website trading halts included shares of wells fargo wfc 3m mmm morgan stanley ms verizon vz and mcdonalds mcd several stocks showed large opening moves that traders said likely triggered circuit breakers that automatically halt trade in individual stocks the nyse said at 948 am that all systems were operational the exchange is working to clarify the list of symbols impacted member firms may consider filing for clearly erroneous or rule 18 claims the nyse said the nyse defines a clearly erroneous execution as one with an obvious error in any term such as price number of shares or other unit of trading or identification of the security stocks were flat to slightly lower in midday trade off of session lows the dow jones industrial average was up 12 points or less than 01 while the sp 500 was off 01 and the nasdaq composite traded near unchanged