The White House and Congress has been evaluating whether to reduce the pre-tax 401(k) contribution limit to potentially as low as $2,400 from $18,000. The move is a way to boost revenue as the government looks to cut taxes.

Economists and budget hawks call this a “budget gimmick,” since it would simply shift revenue that the federal government would collect to the future — essentially, a one-time cash boost.

While Rep. Kevin Brady (R-Tx), the GOP’s chief tax writer in the House, may be looking for immediate income, he told Yahoo Finance at the All Markets Summit that he wants to encourage people to save more — and was looking for alternative means, besides 401(k)s.

However, many consider the 401(k) to be crucial in retirement savings over the past half century making one question very important: What happens to saving behavior if the 401(k) changes?

People who are not financially literate might be hurt

“The average contribution last year was about $6,000. So limiting it to $2,400 would be a big whack,” Olivia Mitchell, a professor at the Wharton School of the University of Pennsylvania and executive director of the Pension Research Council, told Yahoo Finance.

Mitchell said the biggest impact will be on those who are not financially savvy, which could be many people.

“We know people are very financially illiterate so they tend to take what the employer puts in as the default, as advice,” she said. “Even if it’s not meant to be advice.”

So, for example, people who might be saving $6,000 — and probably should be saving even more — might take a new $2,400 cap as government-approved advice on what they should be doing. “That could have a big impact decreasing retirement savings,” said Mitchell.

Vanguard and Fidelity, titans of the retirement savings industry, share Mitchell’s analysis.

In an email, a Vanguard spokesperson noted that the company “is concerned over any legislation that would negatively impact investors’ ability or incentive to save for retirement.”

Looking at the issue with the benefit of significant data, David Gray, senior vice president of workplace retirement plan solutions at Fidelity, echoed Mitchell’s idea that a lower cap would be seen as advice.

Important nudging tools will lose their effectiveness

The 401(k) has been one of the most effective tools to get Americans to save because of auto-enrollment, Gray told Yahoo Finance.

“Plans that use auto-enrollment have 86% participation while plans that don’t leverage auto-enrollment are only at 51% participation rates,” said Gray. “We are concerned that if we have low tax threshold pre-tax, such as $2,400, employers may only auto-enroll [employees] up to that level. There would be real impact on retirement participation.”