Energy Transfer Is Back to Dealmaking With SemGroup Buy (1)

U.S. pipeline giant Energy Transfer LP agreed to acquire rival operator SemGroup Corp. for about $1.35 billion in a stock and cash deal, building out billionaire Kelcy Warren’s empire even as investors demand financial discipline.

Energy Transfer is buying SemGroup for $17 a share, 65% higher than SemGroup’s closing price Friday, Sept. 13, according to a statement. It’s the latest consolidation move by deal-hungry Warren, who last year made a run at NuStar GP Holdings LLC but was rejected when the target company said it was sticking to a plan to simplify its corporate structure.

Energy Transfer shares ...