H&R Block’s chief financial officer has stepped down, the company announced Monday.

William L. Trubeck’s resignation is effective immediately, but he will be a consultant through December. Becky S. Shulman, senior vice president and treasurer, was named acting chief financial officer. Trubeck also was an executive vice president.

The company gave no further details about the resignation of Trubeck, who served amid some of the most difficult months in H&R Block’s 53-year history.

The collapse of the subprime mortgage market has hurt H&R Block’s Option One Mortgage Corp., generating millions of dollars in losses. The company also has faced criticism from investors, who in September replaced three members on H&R Block’s board of directors with activist shareholder Richard Breeden and two of his appointees.