Decade-old healthcare-oriented hedge fund Cooper Hill Partners is closing up shop.

A series of funds managed by the New York-based alternative investment company were reporting average Sept. 11 year-to-date losses of more than 10%. The downward action compelled investors in the fund, which managed some $300 million in assets, to head for the hills.

Cooper Hill had been a long/short player in a number of healthcare and biotech company names including Amylin Pharmaceuticals ( AMLN), Genentech ( DNA), St. Jude Med ( STJ) and Assisted Living Concepts ( ALC).

Rumors of Cooper Hills' slide had been floating around Wall Street since late August. Calls to officials at the firm's New York office were not immediately returned.

In a letter distributed to investors announcing the funds' closure, portfolio manager Alex Casdin said declines in asset values and redemptions caused strains on the firm's infrastructure. "In short, we were faced with a situation where we could not guide for the long term while looking in the rear view mirror," Casdin wrote.

The closure of the hedge fund was first reported by hedge fund industry newsletter Alternative Investment News.