Under the terms of the deal, Sempra would pay $9.45 billion in cash and finance the deal with a combination of its own debt and equity, third-party equity and an expected $3 billion in investment-grade debt at the reorganized holding company. The deal still needs the approval of the Public Utility Commission of Texas, U.S. Bankruptcy Court of Delaware, Federal Energy Regulatory Commission and the U.S. Department of Justice.
The development represents a rare blow for Buffett, who avoids bidding wars for companies and had swooped in two months ago to buy Oncor after two previous attempts by Energy Future to sell it were blocked by Texas regulators.
Elliott voiced its support of the Sempra deal Monday, saying in an emailed statement it provides "substantially greater recoveries" to all Energy Future creditors than Berkshire's offer.
If approved, the acquisition would be a massive one for Sempra Energy, which has a market value of about $30 billion.
San Diego-based Sempra is the mystery bidder that was mentioned at an Aug 18 bankruptcy hearing, according to people familiar with the matter.
Sources told Reuters earlier that Sempra had decided to make an offer for Oncor in the last three weeks, after seeing the opposition that Berkshire faced from Elliott.
In 2014 EFH, which was the 2007 product of the largest ever leveraged buyout, filed for bankruptcy after years of struggling against the shale boom, which drove down prices for electricity as well as gas.
Elliott also tried to put together its own bid for $9.3 billion to buy Oncor.
Sempra Energy expects the transaction to be completed in the first half of 2018. Both saw pushback from consumer advocates - those concerned about the deals' impact on Oncor's financial health, independence and rates it charges - and failed to gain full approval from the state's Public Utility Commission. The Dallas-based Oncor holding company, formerly TXU Corp., at the the time struck agreements with key stakeholders to cut about $40 billion in debt, lower interest expenses, access additional capital "and create a sustainable capital structure for the future".
Allen Nye, who is now Oncor's general counsel, will succeed Bob Shapard as the company's CEO.
Sempra Energy said it would also commit $7.5 billion over five years to expand and reinforce Oncor's transmission and distribution network.