A large Philadelphia pension fund would rather quit its lucrative position as lead plaintiff in a stock-drop class action than dump a hometown law firm as counsel.

In an unprecedented move in securities litigation, the Philadelphia Board of Pensions and Retirement told Northern District Judge William Alsup earlier this month that it no longer wanted to serve as lead plaintiff in a massive class action against Network Associates Inc. Network Associates, a Santa Clara antivirus software maker, was sued by dozens of investors after it announced in April that it had made serious bookkeeping errors that artificially inflated its stock price.