International Business Machines Corp., the largest computer-services provider, drew fire from a worker organization for a change to its 401(k) retirement plan that cuts the frequency of company contributions to once a year.

The company will switch from matching employee contributions to their 401(k) plans twice a month to every Dec. 15, a move that “shortchanges IBM employees,” Alliance@IBM said on its website. While the amount that employees receive isn’t changing, workers who leave before Dec. 15 won’t get their payment for the year.

IBM’s move may set a precedent for companies looking for savings in employee benefits, said Dan Kravitz, president of Kravitz Inc., which administers about 1,000 retirement plans. While IBM isn’t the first company to move to matching contributions once a year, the practice is less common than including 401(k) deposits with each pay period, he said.

“I wouldn’t be surprised if other employers started to look at this for their plan,” Kravitz said in an interview. “Requiring employees to stay through the end of the year to get a match would be pretty significant cost savings for such a large employer.”

Alliance@IBM, which is affiliated with the Communications Workers of America, has asked IBM management to reinstate the semi-monthly plan. The group is trying to organize workers at the company with the goal of forcing IBM to engage in collective bargaining.

Doug Shelton, a spokesman for Armonk, New York-based IBM, didn’t respond to a request for comment.

IBM shares gained 1.2 percent Friday to $191.95 in New York. The shares had climbed 3.2 percent this year through Thursday.