At the end of the calendar year, Lucent will have to make a separate pension calculation, using a different methodology.

A temporary rule change for pension calculations has been helpful to business, but it is due to expire at the end of this year.

Since 1987, companies have been required to use the 30-year Treasury rate as a factor in their pension calculations.

The discount rate is the most powerful of all the actuarial assumptions used in pension calculations.

White-collar workers are shown by statistics to live longer, he said, but the bill would not require companies to factor that into their pension calculations.

He also said that pension calculations were "the subject of much debate."

But even in 2000, about 40 percent of the reported operating income, $951 million, was the result of pension calculations.

The bill that now goes to the House would change pension calculations in a more modest way and would apply for the next three years.

Companies have lobbied hard in recent months to change a key interest rate used in pension calculations.

Actuaries keep track of these differences in a running balance, and incorporate them into pension calculations slowly.