Caesars Entertainment, the casino resorts and online gaming company, suspended its 401(k) match in 2009, when it was 50 percent of employee contributions up to 6 percent of pay, not exceeding the federal cap. When the company reinstated the match three months into 2012, the maximum contribution was $450 for that year, and it was $600 for all of 2013. Gary Thompson, a company spokesman, declined to comment on the change.

Hewlett-Packard lowered its match during the financial crisis from 6 percent to 4 percent, where it has stayed.

“The change was made to align with comparative companies,” said HP spokesman Michael Thacker.

Huge Difference

A few percentage points up or down can make a huge difference come retirement day. A 25-year-old worker with a starting salary of $25,000 whose employer matched 3 percent would see his or her 401(k) balance reach about $624,000 if he or she saved consistently until age 65 and got 6 percent annual returns, according to calculations by Jack VanDerhei, research director at the Employee Benefit Research Institute.

All things being equal, that person would have about $812,000 -- or 30 percent more -- if his or her company matched 6 percent. The analysis assumes an annual wage growth of 3 percent so the worker’s ending salary at age 65 is $81,550.

“Top executives with high compensation likely don’t care what their company contributes to a 401(k), but for employees in the ranks it can mean the difference between financial security and scarcity in old age,” said Mike Alfred, CEO of BrightScope, a San Diego firm that ranks retirement plans.

Some companies, especially small businesses, offer no match at all. The number of 401(k) plans that contribute declined 3 percent in 2012, according to a survey of government filings of more than 400,000 plans by American Investment Planners, a financial adviser in Jericho, New York.

Vesting Periods

Companies also save costs through lengthy vesting requirements, forcing employees who leave to forfeit unvested contributions. Employees at Oracle, for instance, are 25 percent vested after one year of employment, another 25 percent after a second year and only fully vested after four years. In 2012, Oracle used $3 million in nonvested payments to offset its matching contribution obligations, according to government filings. An Oracle spokeswoman, Deborah Hellinger, declined to comment.