Chevron closed its $55 billion acquisition of Hess on Friday after winning a landmark legal battle against larger rival Exxon Mobil to gain access to the largest oil discovery in decades.

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.

Arbitrators cleared the way for the long-delayed $53 billion acquisition after Exxon tried to pre-empt the deal.