Chevron has officially completed its $53 billion acquisition of Hess Corporation, gaining a foothold in one of the world’s most significant oil discoveries, after ExxonMobil’s arbitration challenge was dismissed.

The dispute centered on Exxon’s claim to a right of first refusal for Hess’s 30% stake in the Stabroek block offshore Guyana—a prolific oilfield estimated to hold over 11 billion barrels of crude. Exxon, the project’s operator, initiated arbitration with the International Chamber of Commerce (ICC) in March 2023, asserting that Chevron’s acquisition violated joint venture agreements.

However, the ICC ruled that Exxon’s pre-emption rights didn’t apply since Chevron was acquiring all of Hess, not just its stake in Stabroek. The decision cleared the path for Chevron to close the deal just hours after the verdict.

Chevron CEO Mike Wirth had made it clear that the company would abandon the deal if the ruling went against them. The ICC decision is expected to bolster industry confidence in large-scale M&A, affirming that asset-level rights do not supersede full corporate acquisitions.

Market reactions were swift: Hess shares rose 8% and Chevron’s climbed 3% on Friday, while Exxon shares dipped slightly.

Separately, the U.S. Federal Trade Commission lifted an earlier restriction on John Hess joining Chevron’s board, reversing concerns over alleged coordination with OPEC—claims Hess has denied.

The acquisition significantly boosts Chevron’s reserves, which had fallen to a decade low, and positions the company to benefit from Stabroek’s projected $182 billion in oil and gas revenue over the next 15 years.

Despite expressing disagreement, Exxon stated it would respect the ICC’s ruling, citing its responsibility to shareholders in pursuing the arbitration.