The U.S. Securities and Exchange Commission has launched a formal investigation of Portland hedge fund Grifphon Asset Management, according to a lawyer who represents some of the fund's disgruntled investors. Grifphon first ran into trouble around 2009 when investors started trying to withdraw money from its various funds. "There are a lot of occasions that the SEC is asked to look into something," said Public Companies and Securities Partner Mark von Bergen. "If they see something of fairly large significance they will launch an informal investigation. If they think there is something that is pretty solid in terms of a violation of securities laws, they'll convert to a formal investigation, which is very serious."