The New York Stock Exchange knocked off a bit early on Wednesday, four minutes early to be exact. Instead of the normal 4 p.m. closing time, stocks stopped trading hands at the world's largest market at 3:56.

Perhaps traders decided to start happy hour a bit early on a lovely June afternoon?

Not exactly. Turns out the early exit came courtesy of a technical glitch, namely a communications malfunction in the system that sends electronic orders to the floor.

"All of a sudden we were standing there and orders stopped coming into the books," said one NYSE trader, who spoke on condition of anonymity because he was not authorized to speak on the matter.

The NYSE, for its part, issued a terse statement at 5:20 p.m. blaming the shutdown on a "communications matter." All orders that came in after 3:56 p.m. were canceled and must be reentered when the exchange opens at its usual 9:30 a.m. Thursday.

The trader said chief executive John A. Thain and other exchange executives rushed to the floor after the early shutdown to discuss whether they could reopen and finish out the day.

But word on the floor was that too much news had come out about stocks and too many Wall Street firms had sent traders home to reopen the market with any certainty of fairness to all investors.

"They made the right decision not to reopen," the trader said. "There was news on stocks. And how could we know exactly when orders came in?"

The trader said he recalled a similar shutdown in the 1980s and said everyone appeared to take Wednesday's mini-meltdown in stride. "No one was running around screaming or anything," the trader said. "People were just staring at each other, wondering what was going on."

In fact, there was at least one more recent incident. Trading stopped for nearly an hour and a half on the morning of June 8, 2001, because of computer connectivity problems.

A man leaves the New York Stock Exchange yesterday, when trading shut down at 3:56 p.m. The NYSE blamed a "communications matter."