NEW YORK - The nation's largest companies continue to move away from traditional pension plans, with more than four in 10 now offering new workers only defined-contribution accounts such as 401(k)s, according to a survey released this week.

Just 31 of the nation's 100 largest companies offered traditional pension plans in 2006, according to a study by Watson Wyatt Worldwide Inc., a human resources consulting and management firm. That is down from 35 in 2005 and only about one-third of the 89 that offered traditional pensions in 1985, the study indicated.

As of last year, 42 of the companies had moved to defined-contribution plans, like 401(k) accounts, which require employees to play a major role in funding their retirement savings. That is up from 37 in 2005 and 10 in 1985, the study showed.

The rest - 27 companies - were using so-called hybrid defined-benefit plans, such as cash-balance plans. These pension programs offer a guaranteed benefit like a traditional pension, but generally provide longtime workers with less in accrued benefits than traditional plans. That was down from 28 in 2005 but up significantly from the single plan offered in 1985.

Watson Wyatt, which is based in Arlington, Va., expects further growth in the hybrid plans, especially after recent legislative changes and legal decisions have taken some of the uncertainty out of the programs.

Last summer, a federal appeals court reversed a lower court's finding that International Business Machines Corp.'s cash-balance pension plan discriminated against older workers. In January, the Supreme Court refused to review the case.

Also, the Pension Protection Act, which went into effect in August, contained a number of provisions that should give companies more confidence if they shift to hybrid plans, said Kevin Wagner, a senior retirement consultant at Watson Wyatt.

"A number of Fortune 100 companies are strongly considering hybrid pension plans," Wagner said. "So we expect, by this time next year, an increase in both hybrid" and defined-contribution plans.