Southeast Asia startup Sea Ltd has filed for a potential U.S. initial public offering that could raise about $1 billion, Bloomberg reported on Tuesday, citing people familiar with the matter.The company, which was earlier known as Garena, filed confidentially with the U.S. Securities and Exchange Commission and is looking forward to list itself in early 2018, Bloomberg said.Goldman Sachs (GS.N) and Morgan Stanley (MS.N) are serving as underwriters.Singapore-based Sea did not immediately respond to an email seeking comment.