Sempra is expected to first seek approval from Texas regulators for its $9.45bn takeover offer for Oncor, the giant power transmission system and wind energy distributor, after discarding a competing bid by a company owned by billionaire Warren Buffett.

Last week, California-based Sempra submitted a surprise offer for bankrupt Energy Future Holdings Corp. (EFH), owner of 80% of solidly profitable Oncor, its key remaining asset (including debt, deal has $18.8bn