The halt started just after 11:30 a.m. ET, after which U.S. stocks slightly extended their losses, but in low volumes, with the S&P 500 hitting a session low and the Dow Jones Industrial Average and Nasdaq both falling more than 1 percent. “The issue we are experiencing is an internal technical issue and is not the result of a cyber breach,” the NYSE said in a tweet. There’s no sign of panic at all,” Mark Otto of market maker J. Streicher & Co in New York said from the NYSE floor.