Nationstar Mortgage Holdings aims to raise $400 million through the sale of common stock to finance new growth opportunities in subservicing delinquent home loans, as well as in originating and securitizing new mortgages. Texas-based Nationstar, the home finance unit of Fortress Investment Group, announced the filing of an initial public offering with the Securities and Exchange Commission. Nationstar said it sees opportunities in the current residential mortgage market for non-bank servicers to grow their portfolios by acquiring mortgage servicing rights, entering into subservicing contracts and by assuming responsibilities for...