The U.S. Federal Trade Commission allowed Chevron's $53 billion purchase of Hess Corp. Monday, in an order that barred Hess CEO John Hess from Chevron's board.

The FTC's order leaves Exxon Mobil's challenge to the deal, which is expected to stretch deep into next year, as its final hurdle.

The proposed merger included a Chevron board seat for Hess when it was first announced last October, and the FTC sent a second information request to Chevron two months later.

Exxon and CNOOC Ltd, Hess's partners in a Guyana joint venture, are challenging the deal by claiming a right of first refusal to any sale of Hess's Guyana assets, the prize in the proposed merger.

A three-judge arbitration panel is due to consider the case in May 2025. Chevron and Hess say a decision is expected by August, while Exxon expects it by September 2025.

The proposed all-stock acquisition is one of the largest in a consolidating U.S. oil and gas industry where several multi-billion dollar deals have been disclosed.