The Securities and Exchange Commission (SEC) faced calls from one of the world's most powerful investment institutions to tighten up rules governing hedge funds at an industry summit in Washington.

Mark Anson, chief investment officer at the California Public Employees' Retirement System (Calpers), called for new rules requiring hedge funds to disclose their losses. "The great concern I have with hedge funds is that they don't disclose their losses in a timely manner. In my opinion more disclosure is needed," he said.