Toscafund Asset Management has become the latest hedge fund firm to seek a restructuring in the face of big loses.

The London hedge fund manager on Monday asked investors they planned to flee its flagship fund, the US$3.5 billion Tosca Fund, which lost 35% in September, one of the worst months on record for the hedge fund industry. The firm said it plans to split the fund into a continuing share class and a redeeming share class, depending on how many investors plan to pull their month from the fund, which is down 52% on the year.

The fund was burned by firm founder Martin Hughes’ bet during the spring on banks, including Washington Mutual. Tosca was the second-largest shareholder of WaMu, which was seized by the U.S. government in one of the largest bank failures in U.S. history last month. Its deposits have since been bought by JPMorgan Chase.

Despite the dismal September news, Tosca said it is confident that at least half of the flagship’s investors will stick with the firm, and that it does not plan to unload any of its large, public stakes.

“It is not necessary to dispose of core holdings,” Mehmet Dalman, vice chairman of Toscafund, said. “The fund believes that the core retained holdings offer excellent value.”