Thompson’s withdrawal from his health care firm comes six weeks after federal raids of his home and offices. (C-SPAN)

Jeffrey E. Thompson, 56, resigned Friday from the board of D.C. Chartered Health Plan, which holds a lucrative city contract to manage health care for low-income District residents. That contract, worth as much as $322 million yearly, is the city’s largest and accounts for nearly all of Chartered’s business.

David D. Wolf, a former executive vice president of CareFirst BlueCross BlueShield, is replacing Thompson as chairman, the company said.

Thompson and his intersecting political and business interests have been under a microscope since March 2, when federal agents raided his home and offices. His name was later featured on subpoenas delivered to the campaigns of several D.C. Council members.

Thompson stepped down last month from the board of Thompson, Cobb, Bazilio & Associates, the accounting firm he established nearly three decades ago; partner Ralph Bazilio assumed Thompson’s former roles as chairman and chief executive. Thompson held no executive role at Chartered.

Thompson’s attorney, Brendan V. Sullivan Jr., has declined to comment on the investigation and other aspects of his client’s dealings.

Chartered has been under Thompson’s control since 2000, when he purchased the struggling firm at a bankruptcy sale. In the ensuing years, the company turned itself around and grew to become the city’s dominant health-care contractor. According to Chartered’s most recent regulatory filings, the company now handles the health care of more than 110,000 city residents.

Karen Dale, a spokesman for Chartered, said there have been no changes in the company’s ownership “at this time.”

Thompson notified the company’s board and management of his decision to step down Friday, Dale said, but gave no reason for doing so. The remaining board members voted over the weekend to install Wolf as chairman, she added.

“We’re delighted to have someone of Mr. Wolf’s caliber coming on board,” she said.