Employers are squeezing their workers’ retirement savings, holding back on both the amount and the timing of 401(k) matching funds and dragging out vesting schedules. Taken together, these measures are making it more difficult to save for old age.

Major companies that have engaged in such practices in recent years include Whole Foods Market Inc., Facebook Inc., Oracle Corp., Caesars Entertainment Corp. and JPMorgan Chase & Co.

The most frugal have been scaling back company matches and setting lower limits for the maximum annual payment they’ll make to a 401(k) account, according to hundreds of government filings analyzed by Bloomberg. A difference of three percentage points on a match can add up to hundreds of thousands of dollars lost for employees over the course of their careers.

“There’s been an implicit contract for years and years -- workers save and companies match -- but now they’re changing the rules,” said Brigitte Madrian, a Harvard Kennedy School professor who studies retirement policy and corporate management. “Most individuals can’t do it on their own. We’re going in the wrong direction.”

Companies including International Business Machines Corp. and Hewlett-Packard Co. say their 401(k) policies are partially dictated by bottom-line considerations and marketplace competition. Others say that when setting their 401(k) contributions, they consider a wide range of benefits and their costs as well as employee preferences, including health care, vacation policy and incentives such as performance bonuses, stock options and outright grants.

Choosing Benefits

“In addition to our 401(k) plan, we offer benefits that our more than 80,000 Team Members have the opportunity to actually vote on, including paying only $0-$15 per paycheck for health insurance premiums, robust store discounts, and paid time off that carries over,” Mark Ehrnstein, global vice president of Team Member Services at Whole Foods, said in an e-mail. “We offer other benefits such as a broad-based stock plan that awards 95 percent of options to non-executives, and we have a gain-sharing program that rewards teams for labor productivity.”

The advent of 401(k) retirement savings since the late 1970s was supposed to help secure and boost the retirement savings of baby boomers. The plans, originally conceived as a supplement to pensions, have since mostly replaced them. Workers can direct up to $17,500 of pretax income toward their 401(k)s this year and an additional $5,500 for those aged 50 and older.

Control, Portability

The investment industry has said for the past 30 years that 401(k)s are a big improvement over pensions, giving employees more investment choice, more control over retirement planning and more portability amid the frequent job changes of the modern workforce. That, at least, was the promise held out by the industry that now holds $4 trillion in retirement assets.