Nasdaq's order-routing system shut down shortly before the close of trading Wednesday, suspending transactions on the exchange. There has been no word on what caused the outage, although the exchange saw a higher-than-usual trading volume of 2 billion shares before the problem.
Exchange staff noticed at 3:40 p.m. Eastern time that the quote system, SelectNet, was unable to provide quotes. Nine minutes later, SelectNet and the small-order-execution system were suspended, then restored shortly before 4 p.m., a Nasdaq spokeswoman says. She couldn't say how long the systems were down.
Investors were unable to update and view quotes until after the market closed, she says. After-hours trading was proceeding as usual Wednesday evening, according to the spokeswoman.
The exchange had similar problems April 4, when it struggled to handle record volume. Investors traded an estimated 2.9 billion shares on the Nasdaq and requested 6.5 million quote updates, surpassing the previous record of 5.8 million requests. That caused update delays in SelectNet for about 75 minutes. Trading continued uninterrupted.