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.

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. Most Read from BloombergThe Dutch Intersection Is Coming to Save Your LifeMumbai Facelift Is Inspired by 200-Year-Old New York BlueprintAdvocates Fear US Agents Are Using ‘Wellness Checks’ on Children as a Prelude to ArrestsLA Homelessness Drops for Second YearManhattan,