An affiliate of activist investment firm Elliott Investment Management, Amber Energy Inc, has emerged as the leading bidder in the auction for Citgo Petroleum Corp’s parent company with a $7.3bn offer, according to a report by Bloomberg.

This marks a significant milestone in Elliott’s quest to gain control of an oil refiner that was once Venezuela’s most valuable foreign asset.

The report cites a filing by Robert Pincus, the court-appointed special master overseeing the process, as revealing that Amber Energy submitted the top bid for Citgo’s US parent, PDV Holding. Pincus has yet to submit a formal recommendation though, and the the bid still requires approval from US District Judge Leonard Stark in Delaware.

Following Pincus’s final recommendation, other interested parties will have a 45-day window to submit competing bids for Citgo. Elliott will retain the right to withdraw its offer if the court allows other creditors to stake their claims through separate lawsuits.

The sale of Citgo is aimed at compensating creditors who hold more than $20bn in claims against Venezuela. And while Amber Energy outbid several other contenders vying to take control of the business from Venezuela’s state-run oil company, Petroleos de Venezuela SA (PDVSA), the 'winning' offer would leave many creditors without a full recovery.

The proposed acquisition also faces additional hurdles, including approval from the US Treasury Department’s Office of Foreign Assets Control, as Citgo is currently protected under US sanctions against Venezuela in response to ongoing political unrest in the country.