Exxon Mobil Corp. appears to be nearing the end of a second review by the Federal Trade Commission as it seeks to wrap up a more than six-month quest to acquire Pioneer Natural Resources.

Bob Brackett, an analyst at Bernstein, wrote in an April 26 report that few obstacles remain to “an imminent 2Q close on Pioneer.”

“Should XOM [Exxon] have complied with the FTC’s 2nd request, the 30-day review period likely began in early April,” Brackett said.

Under the Hart-Scott-Rodino Antitrust Improvements Act, deals are reviewed by the FTC for 30 days. A second request of information restarts the 30-day review period.

Exxon Mobil’s $59.5 million deal to acquire Pioneer will bring together two of the largest crude oil producers in the Permian Basin.

During Exxon’s April 26 earnings call, Chairman and CEO Darren Woods said the companies had supplied the commission with “an enormous amount of material, documents, contracts [and] line items on productions and sales.”

Woods added that the transaction had been through a “very thorough review.”

“As we've said all along, we're very confident that there are no antitrust issues, and I would just say we're very optimistic that … we'll meet the objective that we said very early to close in the second quarter,” Woods said.

The FTC has aggressively reviewed several upstream oil and gas deals since last year. Most recently, Diamondback Energy’s $26 billion merger with Endeavor Energy Resources was delayed by an additional request for information from the FTC.

In April, Chesapeake Energy’s $7.4 billion merger with Southwestern Energy was delayed by additional oversight, as was the $53 million merger between Chevron and Hess Corp.