An $8bn (€6bn) US state pension is suing Amaranth Advisors for handing its money to an "an absentee rookie trader", which will frustrate plans to distribute funds to investors as quickly as possible, according to the collapsed hedge fund.

The San Diego County Employees Retirement Association said in a statement it had filed a complaint for securities fraud against Amaranth Advisors; Nicholas Maounis, chief investment officer; Charles Winkler, chief operating officer; Robert Jones, chief risk officer; and the hedge fund's former natural gas trader Brian Hunter.