National Power Co. will stand behind its promise of a low, fixed electricity rate after all, thanks to pressure by the Public Utility Commission.

The Houston electricity retailer informed some customers last week that their fixed rate of around 11 cents per kilowatt-hour would rise to around 15 cents in 45 days. Customers could terminate the contract without paying the usual $300 penalty.

Nearly 400 customers complained to the Public Utility Commission, which began to investigate on Wednesday.

On Thursday, the company met with PUC staff members and announced it would forgo the rate increase.

"All fixed-rate pricing and terms shall remain as originally agreed," National Power chief financial officer David Barrett said in an e-mail.

"National Power Co. apologizes for any confusion caused by the rescinded letter. All customers to whom the rate increase letter was sent ... will receive additional confirmation via mail."

He didn't say why the company wanted to hike rates, or why it chose not to. Mr. Barrett didn't respond to e-mails or phone calls.

PUC spokesman Terry Hadley said the commission isn't ready to conclude its investigation just yet. And the commission hasn't returned National Power's offers to the powerto choose.org consumer Web site, after dropping the company on Wednesday.

"We're still getting calls in to our customer protection division, so we're not prepared at this time to wrap it up," Mr. Hadley said.