LONDON (Bloomberg) - Frontline Ltd. and companies controlled by its chairman, Norwegian billionaire John Fredriksen, hold 4.9 percent of the shares of Overseas Shipholding Group Inc., according to a regulatory filing.

Bermuda-based Frontline Ltd. said in the July 10 filing it plans to talk with Overseas Shipholding management and other investors to look at ways to increase shareholder value. That may include "combining with or acquiring control" of its competitor.

Overseas Shipholding, based in New York, operates a fleet of 117 vessels, according to the company's website.