WASHINGTON — With pension funds facing billions of dollars in shortfalls as markets plunge, a range of companies from Ford to Verizon are pushing Congress to suspend portions of a two-year old law they say could force them to make job cuts as they shift scarce money into ailing retirement pools.

The lobbying effort aims to change a 2006 pension reform law as part of any economic stimulus plan in a lame-duck session of Congress that begins next week. Companies warn the current law could force them to tie up large sums of cash they need in the face of a global recession.

Roughly 300 companies and business groups plan to make the request in a letter Wednesday to congressional committees. The authors include some of the nation's biggest corporate names from a wide range of sectors, including Ford Motor Co., IBM Corp., Pfizer Inc. and Verizon Communications Inc.

The Pension Protection Act of 2006 included provisions meant to ensure that company pensions, also known as defined benefits, have money to meet the promises made to workers and retirees. While many companies have phased out such pools of money in favor of 401(k) plans, which cost less, about three-quarters of S&P 500 companies still have traditional plans, analysts say.