Diamondback Energy's buyout of Double Eagle could signal the winding down of the rapid consolidation of the Permian Basin over the last half decade.

Diamondback Energy said on Tuesday it would buy certain units of EnCap Investments-backed energy producer Double Eagle for $4.08 billion in cash and stock, expanding its presence in the oil-rich U.S.

Diamondback Energy Inc. is closing in on a deal to acquire closely held West Texas oil producer Double Eagle in a bid to further its dominance in the world’s biggest shale patch, according to people familiar with the matter.