Just a glitch, or something.

Via NBC Washington:

Trading in all symbols was temporarily halted on the New York Stock Exchange floor Wednesday due to an apparent technical issue, CNBC reported. “NYSE/NYSE MKT has temporarily suspended trading in all symbols. Additional information will follow as soon as possible,” the NYSE said in a statement on its status page Wednesday. A technical issue caused the trading halt, Reuters reported, citing a source. Trading stopped around 11:30 a.m. ET. Two U.S. officials told NBC News that there’s no indication that the computer problems at United Airlines and the New York Stock Exchange are related. The Wall Street Journal’s home page also appeared to be down for some users.