Alleged Fraud Surprises Activist Investors in Shipping Fuel Company

Board investigation found billionaire founder used false transactions, receipts and documents to conceal alleged $300 million fraud

In May, an activist-investor group forced its way onto the board of a Greek shipping-fuel company, calling it mismanaged and undervalued.

Six months later, that company, Aegean Marine Petroleum Network Inc., has filed for bankruptcy, with its new board alleging that the company had been systematically plundered and the assets that drew the activists’ attention were largely fake.

An...