Texas regulators rejected a plan by NextEra Energy to acquire Oncor Electric Delivery Co. for $18.4 billion. The sale was seen as key to ending the bankruptcy of Oncor parent Energy Future Holdings Corp.

The Public Utility Commission of Texas voted against the deal on April 13. The action followed a draft order showing the merger would not be in the public interest. Regulators expressed concern in March about the loss of ring-fencing measures designed to protect Oncor’s credit rating.

The news was reported by Bloomberg.

A previous merger attempt from a group backed by Hunt Consolidated Inc. failed in 2016 when Texas set conditions that Hunt rejected. Energy Future, created by one of the largest leveraged buyouts on record, sought bankruptcy court protection in 2014 to restructure almost $50 billion in debt.

NextEra, owner of Florida’s largest utility, agreed to buy Energy Future’s 80% stake in Oncor in 2016 in a transaction valued at more than $18 billion, including debt. A bankruptcy judge approved the sale in February.

In the draft order rejecting the latest takeover bid, the commission’s staff cited “substantial amounts of leverage at NextEra” that would pose a financial risk to Oncor and offer few benefits to customers. Issue was taken with “ring-fencing” measures that NextEra proposed to end as part of the takeover to link its credit profile with Oncor’s.

Oncor serves 10 million Texas customers and has 121,000 miles of distribution and transmission lines.