HARRISBURG — Pennsylvania utility regulators says they'll look into complaints about spiking electric bills, saying the affected people had signed variable-rate contracts with suppliers that then passed on wholesale prices driven up by cold weather.

The Pennsylvania Public Utility Commission voted unanimously on Thursday to review the policies and rules around what regulators call electric generation suppliers that buy and sell electricity.

The utility commission doesn't regulate their rates, but it does regulate their conduct and marketing practices. It says it's received more than 750 informal complaints from consumers about bills.

The complaints are arriving as policymakers in Harrisburg consider legislation that would bring more business to the suppliers by auctioning off the accounts of millions of Pennsylvania households that are still served by traditional utilities. The AARP opposes the bill.

NEW YORK — Express Scripts, the largest U.S. pharmacy benefits manager, said its fourth-quarter net income slipped, hurt by the loss of UnitedHealth, a large customer. Charges related to its $29.1 billion purchase of Medco Health Solutions in 2012 also weighed on profit.Pharmacy benefits managers run prescription drug plans for employers, insurers and other customers. They process mail-order prescriptions and handle bills for prescriptions filled at retail pharmacies. Express Scripts fills more than a billion prescriptions a year.Express Scripts Holding said Thursday that it earned $501.9 million, down from $504.1 million in the final quarter of 2012.