Renewable Energy Group Inc., the largest U.S. biodiesel producer, expects to price its initial public offering between $13 and $15 a share. The company plans to sell more than 6.8 million shares of its common stock, it said today in a filing. Shareholders Bunge Ltd., ED&F Man Holdings Ltd., NGP Energy Technology Partners, US Renewables Group LLC and West Central Cooperative are offering an additional 342,860 shares.