The Senate passed a bill this week that would allow companies to use a 25-year average of corporate bond yields when calculating their defined-benefit pension liabilities. If the measure becomes law, it could greatly reduce the contributions companies have to make to their pension plans, but it's not clear whether the House will adopt the Senate provision.

The Senate measure is contained in S. 1813, a transportation funding bill. Kathryn Ricard, senior vice president of retirement policy at the ERISA Industry Committee, which represents major U.S. employers, says that a bill to extend transportation funding that the House produced in February did not include the pension provision.

The current transportation funding measure expires on March 31. With Congress due for a two-week Easter recess, Ricard says the House may enact a temporary extension to transportation funding, or a longer extension that postpones deliberations until the lame duck session at the end of the year.