Trading Resumes On New York Stock Exchange

Updated at 3:15 p.m. ET

Trading has resumed on the New York Stock Exchange, after computer related problems forced the exchange to suspend trading for more than three and a half hours.

The exchange "temporarily halted" trading as of 11:32 a.m. ET; trading resumed at approximately 3:10 p.m. ET.

The NYSE released a series of Tweets in which it said the issue was technical and not due to malicious activity:

The FBI offered its assistance to the exchange, but the NYSE said no further action was needed. The White House says President Obama had been briefed on the trading halt and the Treasury Department is monitoring the situation.

Securities and Exchange Commission Chairwoman Mary Joe White issued this statement:

"We are in contact with NYSE and are closely monitoring the situation and trading in NYSE-listed stocks. While NYSE is working to resolve the situation, NYSE and NYSE MKT stocks continue to trade normally through other trading venues."

About an hour before trading was halted, the exchange said it had a technical issue that had been resolved.

The exchange says all open orders at the time of the shutdown will be canceled.

Trading continued on Nasdaq and other markets, which include stocks also traded on the NYSE.

Before the halt, the Dow Jones Industrial Average and the broader S&P 500 were down.

The Washington Post spotted this chart from Eric Scott Hunsader, founder of the market data and analytics firm Nanex, illustrating the dramatic drop-off in NYSE trading activity:

Despite the big brouhaha over the NYSE's troubles, to investors, the trading halt on Wall Street may not mean much of anything. The Wall Street Journal explains why:

"No exchange has exclusive rights to trade any stock or exchange-traded fund, except during the opening and closing of trading. Apart from those brief periods, trading takes place at any of a dozen exchanges and more than 40 private trading venues, known as dark pools.

The Journal says the NYSE has handled about 20 percent of all U.S. stock trading in recent months, with Nasdaq and BATS Global Markets a bit less. About the only investors who would notice the NYSE halt are those with trades pending:

"Outages could hurt traders and investors if they have orders sitting on the order book of an exchange that has a problem. So, if an institution has an offer at an exchange to buy 1,000 shares of Apple Inc. at a certain price, and the market stops trading, it can cause uncertainty. The institution might not be able to find out whether its order traded, and it could have trouble canceling the order. The NYSE said in a note to traders that all open orders had been canceled except the long-term requests to buy or sell put in by institutions that are known as "good-till-cancel" orders."

The NYSE was not the only large institution to experience computer glitches Wednesday. United Airlines instituted a ground halt for a time Wednesday morning, which it blamed on "connectivity issues." The halt has since been lifted and flights have resumed.

The Journal's website also was down for a time.