Mercuria's swoop to save the troubled Aegean Marine was really the start of a takeover attempt, the former fueling giant's biggest creditors allege.

In court paper, Aegean's bondholders, who are owed a total of $267m in two separate convertible notes, say the July deal between the Swiss commodities trader and the bunker and tanker company was the start of an "aggressive loan-to-own strategy" that took a step forward when Aegean declared bankruptcy in New York federal court Tuesday.

"Despite (Aegean) championing Mercuria as their savior, the Mercuria relationship has been detrimental to (Aegean) and resulted in the commencement of Chapter 11 cases designed to complete Mercuria's acquisition" of Aegean's assets at less than fair value through a sale process, the bondholders wrote.

In the court papers, the group of bondholders asked the court to make significant changes to Aegean's requested $532m debtor-in-possession financing plan.

Mercuria did not immediately respond to requests for comment.

In June, Aegean's credit lines and major refueling hubs had both run dry after a tumultuous year nearly landed the company in liquidation.

Instead, Mercuria stepped in to serve as the company's sole lender in July, providing much-needed liquidity and taking a seat on the company's board.

The group said they had attempted to work on a restructuring plan that June and had a term sheet to provide $50m to finance the 1 November maturity of $94.5m of the notes.

That came a day after the July deal with Mercuria was cut

"From that point forward," the group wrote, "Mercuria improperly exercised control ... to block any meaningful negotiation with other potential financing parties, refusing to consider restructuring proposals that would have avoided the need for the commencement of (bankruptcy)."

The group says they expect "there will be a full and extensive investigation into Mercuria's undue control" and "bad faith conduct" and that the debtor-in-possession financing is "designed solely to benefit Mercuria and is not in the best interest of (Aegean's) estates."

The bondholders' account differs from a declaration filed with the court Tuesday by Aegean director Tyler Baron.

While Baron acknowledges that the ad hoc committee of holders did submit its own DIP plan, he added, "Ultimately the Ad Hoc Group was unable to obtain committed financing from a third party to be able to actually provide DIP financing as of the petition date."