Venture capitalist Jeffrey Ubben (search) stepped down as chairman of Martha Stewart (search) Living Omnimedia Inc., the company said Tuesday, and Thomas Siekman, a former Compaq Computer executive, was named as his successor.

Ubben ended his 14-month tenure as chairman in the wake of Stewart's stock trading scandal, saying in a news release that the company had "weathered a most difficult period associated with Martha Stewart's personal legal situation" and that he wanted to turn the chairmanship over to "someone who has the skills and, most importantly, sufficient time available to guide the board and the company forward from this point."

Ubben, whose company is a primary investor in Martha Stewart Living Omnimedia (MSO), will remain on the board. Siekman has served on the MSO board since Aug. 1, 2003.

In addition, the company announced the resignation Arthur Martinez, former chairman and chief executive of Sears Roebuck & Co. (S), from the company's board. Martinez had been serving as lead director, a position that will no longer be filled. Martinez had been on the MSO board since 2001. No reason was given for his departure.

Martinez will be replaced on the board by Charles Koppelman, chairman and CEO of CAK Entertainment Co. (search), a music and entertainment business. Koppelman was proposed by Stewart herself, the company said.

Stewart resigned as chief executive and chairwoman of the company she founded on June 4, 2003, after she was indicted on charges that she lied to federal investigators about a private stock transaction. Ubben took over as chairman, while Sharon Patrick (search) became president and CEO.

Stewart resigned her board seat on March 15 after she was convicted. She remains on the payroll as founding editorial director.

Stewart was sentenced July 16 to five months in prison and five months of house arrest. She was allowed to remain free while appealing the verdict.

Martha Stewart Living Omnimedia stock rose 29 cents, or nearly 3 percent, to $11.29 on the New York Stock Exchange (search).