Some clients of online broker TD Ameritrade suffered an apparent outage that prevented them from fully accessing their accounts Monday morning.
News about the technical issues emerged about an hour before U.S. stocks opened for trading.
A TD Ameritrade spokeswoman told CNBC the company "encountered an issue in which clients using our trading website were unable to see balance and position information. The ability to trade was not impacted."
The company also said via its Twitter account that it had not been hacked, noting clients could still access their accounts through TD's thinkorswim platform or the Mobile Trader application.
The company's stock closed 3.6 percent higher on Monday.