(Reuters) -The U.S. Federal Trade Commission is probing executives from major oil firms, including Hess Corp (NYSE:HES), Occidental (NYSE:OXY) and Diamondback (NASDAQ:FANG) Energy over their communications with OPEC officials, Bloomberg News reported on Friday, citing people familiar with the matter.
All three companies are pursuing multi-billion dollar deals which are currently under FTC review.
The current investigation of communication with OPEC officials is part of the U.S. antitrust regulator's review, the report said, adding that investigators are looking for evidence of collusion over oil market dynamics.
Earlier this year, FTC barred former Pioneer Natural Resources (NYSE:PXD) CEO Scott Sheffield from Exxon (NYSE:XOM)'s board on allegations that he attempted to collude with OPEC to raise oil prices.
The FTC made the move as it approved Exxon's $60 billion purchase of Pioneer.
Hess, in an emailed statement, said the allegations of improper communications were "baseless and without merit".
Occidental, Diamondback and the FTC did not immediately respond to Reuters requests for comment.
Last month, the U.S. Senate budget committee launched a probe of domestic oil producers, including Exxon and Chevron (NYSE:CVX), about any efforts to illegally coordinate oil prices with the OPEC.