A refund check connected to the federal corporate tax cut is still not in the mail to Xcel Energy customers — and it won't be until at least May.

In August, state utility regulators ordered that Xcel's $138 million windfall from 2017's big corporate tax cut be passed on to its ratepayers. At the time, Xcel said it expected the refunds to be issued by the end of 2018.

Minneapolis-based Xcel, by far Minnesota's largest electric utility, said the delay stems from the state's regulatory procedure.

"We're working through the Public Utilities Commission process and expect our plan to provide one-time refunds and monthly bill credits to customers will happen later this year," the company said in a statement.

Utilities are usually monopolies, so their profits are regulated. Minnesota is one of many states where regulators have ordered utilities to fully or partly refund gains realized from the federal tax cut, which slashed the U.S. corporate income tax rate from 35 percent to 21 percent.

Xcel's average residential electricity customer — someone who pays $85 to $95 per month — will receive a one-time refund of $43.48 for 2018, the company said. Xcel's average gas heat customer will receive $8.93. Electricity customers will see the refund on their bills between May 7 and May 21; natural gas customers between July 2 and July 16.

In addition, Xcel will refund its tax-cut gains for 2019, which amount to an average annual residential credit of $35.90 for electricity customers and $8.38 for gas customers. The 2019 refund will be paid out through monthly bill credits from March 1 to Dec. 31.

While the Minnesota Public Utilities Commission (PUC) ruled on the tax refund in August, it did not issue a written order until Dec. 5. Xcel said it needed the PUC's written order to "finalize our calculations."

The company submitted its tax-refund plans to the PUC earlier this month. A 30-day comment period on Xcel's proposals ends Feb. 14, and if there are no objections, the company said it will move forward with its plan.

Mike Hughlett • 612-673-7003