Treasury Secretary John W. Snow and Federal Reserve Chairman Alan Greenspan warned today that legislation intended to combat trading abuses should not punish investors. "Information and disclosure requirements should be designed to provide investors with real value rather than serve mainly to increase costs and decrease returns," they wrote in a letter Rep. Michael G. Oxley, chairman of the House Financial Services Committee. Mr. Oxley added amendments to HR 2420, the Mutual Funds Integrity and Fee Transparency Act. The House is expected to approve the legislation Wednesday. Among the amendments, the legislation would exempt 401(k) plan participants from the 4 p.m. Eastern time deadline being considered by the SEC for all buy and sell orders. The amendments also would ban joint management of hedge funds and mutual funds by the same portfolio manager, although investment advisory firms would be able to manage money for both hedge funds and mutual funds, and impose a 2% fee on rapid-fire trades to discourage market timers.