NEW YORK (AP) — Technical issues interrupted trading for some investors using TD Ameritrade.

Spokeswoman Kim Hillyer said in an email that the problems, which she described as limited, were caused by a software update that was done overnight. The issue was resolved Friday at about 10 a.m. Eastern, she said.

The halt in trading at TD Ameritrade Holding Corp. comes two days after the New York Stock Exchange shut down for nearly four hours because of problems associated with a software upgrade on the exchange's computers.

It has been a tremendously volatile week of trading and message boards lit up during the Ameritrade outage.