Perhaps the most significant change was the easing of rules regarding retirement plans and annuities, which, in their simplest form, enable workers to convert their savings into a guaranteed income stream.

Many employers have long been reluctant to include annuities in their offerings because they feared being sued if an insurance provider could not make the guaranteed payments — something that could happen decades after an employee has left an organization. The new law eliminates some of the liability for employers.

But consumer advocates and other financial experts said they were concerned that undesirable annuities — often costly and complex ones — could end up among savers’ options, particularly at smaller employers that get less sophisticated advice or don’t look beyond a sales pitch.

“I’m encouraged by the fact that plans could give people the chance for guaranteed income over the course of their lifetime,” said Jeffrey Levine, director of financial planning at BluePrint Wealth Alliance, a financial advisory firm in Garden City, N.Y. “But I am nervous about the wrong types of annuities getting in there — there is potential for abuse. It is kind of a double-edged sword.”

The bill would also allow small businesses to band together to create retirement plans for their workers, which the bill’s supporters say would give them access to investments and administrative services at a lower cost. And it would allow people who put aside money for educational costs in a 529 college savings plan to use up to $10,000 in leftover money in those accounts to pay back student loans — as well as the debt of the beneficiaries’ siblings.