A critical ruling gave Chevron the go-ahead for a $53 billion acquisition of Hess, access to one of the biggest oil finds of the decade, and a big win

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

Exxon Mobil has lost its arbitration challenge to block Chevron's $55 billion Hess acquisition deal, but the top U.S. oil producer managed to delay the tie-up by over a year, costing its rival billions in lost Guyana oil revenue and slowing integration.