BOSTON (Reuters) – For the second time in a week, some clients at Fidelity Investments could not access their online accounts at the powerhouse retail trading brokerage on Monday morning in a glitch described by the company as a technical issue.

The latest problems began early morning, just as investors geared up to make trades in a surging stock market fueled by a tax bill that could slash corporate tax rates to 20 percent from 35 percent.

Fidelity spokesman Mike Aalto said some clients were unable to log in to their accounts during the first hours of trading.

The issue was not resolved until later in the morning, around 11 a.m. EST (1600 GMT), he said.

“We are still looking into what the cause was,” Aalto said.

Boston-based Fidelity, known for its stable of mutual funds, operates a large online brokerage with nearly 25 million customer accounts. Fidelity said Monday’s issue had a sporadic affect on customer accounts.

On Nov. 29, Fidelity clients also experienced problems accessing their accounts because of what the company called an internal technical issue. Fidelity declined to give more details about what caused the issues.

(Reporting By Tim McLaughlin and Svea Herbst-Bayliss; Editing by Chizu Nomiyama and Marguerita Choy)