Exxon Mobil took a significant step toward closing its $60 billion mega-deal to acquire Pioneer Natural Resources after reaching an agreement with the Federal Trade Commission on Wednesday, May 1. Federal antitrust regulators will not block the largest oil and gas deal in two decades after Exxon agreed to exclude former Pioneer Chief Executive Officer Scott Sheffield from its board of directors, according to multiple reports.

The Wall Street Journal reported that the Federal Trade Commission will allege as soon as this week that Sheffield engaged in collusive activity with OPEC representatives, which could have raised gas prices for Americans.

“Pioneer is a clear leader in the Permian with a unique asset base and people with deep industry knowledge,” Exxon Chairman and CEO Darren Woods said in a press release. “The combined capabilities of our two companies will provide long-term value creation well in excess of what either company is capable of doing on a standalone basis.”

Once the agreement is filed, the acquisition could close within days, marking the biggest deal for Exxon since it merged with Mobil in the late 1990s.

Exxon announced in October that it would acquire Pioneer in an all-stock deal valued at $59.5 billion, aiming to more than double its production in the Permian Basin.