After that date, funding pensions will in effect be more expensive, because the deduction on contributions will be of less value, explained Richard McEvoy, a pension consultant with global consultancy Mercer.

“It’s clearly beneficial for sponsors to consider voluntarily funding pension plans,” McEvoy explained in a webinar.

According to data from Mercer, 75 percent of sponsors were considering larger voluntary contributions in anticipation of tax reform passing last year.

In a survey of 241 companies since reform passed, more than three-quarters reported that they will see their effective tax rate reduced. About one-third said they plan to redirect the savings, at least in part, to employee benefit and compensation programs. But 42 percent said they don’t intend to redirect savings to workers, according to Mercer.

Consultants from the firm said the flurry of company announcements on defined benefit and other compensation investments since the reform bill was signed was not expected so soon.

For DB plan sponsors, accelerating contributions by this year’s deadline will create considerable tax savings.

In a simple equation provided by actuarial firm October Three, a plan with $100 million in unfunded liabilities will net $14 million in tax savings if they fully fund the pension before the September deadline, as opposed to waiting until after the deadline.

Moreover, sponsors have the chance to lower the variable rate premiums on unfunded liabilities paid to the Pension Benefit Guaranty Corp.

In 2018, the variable rate is roughly equal to 3.8 percent of unfunded liabilities, and in 2019 it is scheduled to increase to 4.3 percent, or $4.3 million in variable premiums for the hypothetical plan with $100 million in unfunded liabilities.

When accounting for the elimination of variable rate premiums over five years, the value of accelerating contributions is potentially massive.

“When you add it all up, a $100 million pension contribution this year could net $30 million or more to the company. For pension sponsors that are also taxpayers, this is an historic opportunity,” wrote Brian Donohue, an actuary at October Three, in a blog post.

Under pension law, companies are limited in the contributions they can deduct.

And plans that terminate or freeze with a funding surplus are potentially exposed to income taxes on so-called stranded surpluses, and up to a 50 percent excise tax on the value of the extra assets.

“One concern sponsors have about aggressively funding DB obligations is the possibility of a stranded surplus,” notes Donohue.

It’s rare when terminated plans wind up with taxable surpluses, says Donohue. In the event they do, sponsors can merge the assets with another plan’s unfunded liability under the same sponsor. In another option, sponsors can use the surplus assets to fund defined contribution plans for up to seven years after a defined benefit plan terminates.

“In our view, the idea that DB sponsors must ‘thread the needle’ in order to terminate pension plans without incurring excise and income taxes is highly exaggerated,” Donohue wrote.

“Employers can employ a wide range of strategies to make effective use of even large pension surpluses. And given the historic but time-sensitive opportunity related to the 35 percent corporate tax rate for 2017, many employers would benefit from understanding these ideas better,” he added.