Chevron Corp. has prevailed in a 20-month fight to buy Hess Corp. for $53 billion, overcoming a challenge by arch rival Exxon Mobil Corp. that was unprecedented in the modern history of Big Oil.

Chevron completed its $53 billion purchase of Hess after winning an arbitration case brought by rival Exxon Mobil and the China National Offshore Oil Corporation.

Chevron struck the deal to acquire Hess in October 2023. Exxon tried to block the move last year, saying it had a right of first refusal to buy Hess’ Guyana assets because of its joint operating agreement with Hess and the China National Offshore Oil Corp., or Cnooc, for the Stabroek Block.