(Reuters) - Overseas Shipholding Group Inc (OSG.N), the world's No. 2 independent tanker operator by fleet size, said it was evaluating options including filing for bankruptcy protection.
The company's shares were down 57 percent before the bell. The company's shares lost more than a third of their value last week on speculation that talks with its lenders had hit a road block.
Financial statements for at least the three years ended December 2011 should no longer be relied on, the company said in a regulatory filing on Monday.
Overseas Shipholding said it was in the process of reviewing a tax issue as the company is domiciled in the United States and has substantial international operations.
Allen Andreas, a member on the company's board and audit committee, resigned on September 27 over disagreements with the board in reviewing the tax issue.
The New York-based company said it was continuing its review process, including determining whether a restatement of those financial statements may be required.
The company also said it was reviewing the interpretation of certain provisions contained in its loan agreements.
Overseas Shipholding has said it needs to plug a $100 million gap with a $1.5 billion fully-drawn revolving credit facility expiring in four months. Analysts, however, say the gap could be as much as $300 million.
Shares of the company, which has a market value of about $100 million, were down 57 percent at $1.39 before the bell. They closed at $3.25 on the New York Stock Exchange on Friday.
Reporting by Swetha Gopinath and Divya Lad in Bangalore; Editing by Supriya Kurane