Dissident investors including activist hedge fund Jana Partners and Velocity Interactive, the new venture capital firm formed by Jonathan Miller, Ross Levinsohn, and ComVentures, have amassed a 21 percent interest in CNET Networks and plan a proxy fight to gain control of the technology news provider, they said in a government filing Monday.

Jana said that in addition to its 8 percent voting stake in CNET, the hedge fund has an 8 percent non-voting interest and has enlisted Sandell Asset Management, with a 5 percent non-voting interest, as an ally.

San Francisco-based CNET, in a press release, responded by calling Jana's plan a violation of CNET's corporate bylaws, setting the stage for a court challenge. Jana is proposing that company expand the board of directors from the current eight to 13. That would allow the dissidents to gain control of the board if shareholders backed its slate of five new nominees plus two who would challenge company-backed incumbents.

Shares of CNET, whose executive ranks were shaken by the options back-dating scandal, have stagnated in recent years, gaining about 1 percent in 2007 versus 10 percent for the Nasdaq Index. In Monday afternoon trading, CNET shares fell $.06, or .7 percent, to $8.50.

New York City-based Jana said it is seeking an injunction in Delaware Court of Chancery to prevent CNET from rejecting its director nominations. CNET bylaws bar shareholders from nominating directors until they have held their stock for one year, a provision JANA labeled "discriminatory."

Also joining Jana's effort to dislodge CNET management is Alex Interactive Media and Spark Capital.

Paul Gardi, managing member Alex Interactive Media and a former executive at IAC, and Santo Politi, founder and general partner at Spark Capital, are running to unseat CNET-backed incumbents on the board.

The five-nominee slate proposed for the expanded board are: Jonathan Miller, founding partner Velocity Interactive; Javnie Studenmund, former chief operating officer of Overture Services/Yahoo; Julius Genachowski, managing director of Rock Creek Ventures; Brian Weinstein, senior executive, business development at Creative Artists Agency, and Giorgio Caputo, managing director, Jana Partners.

In 2007, Jana and SAC Capital, another activist hedge fund, tried to push online broker TD Ameritrade to merge with a rival such as E-Trade or Charles Schwab.

In 2006, Shelby Bonnie, chief executive and co-founder of CNET, resigned amid a stock options backdating scandal that touched many tech companies, including Apple, Comverse Technology, and Broadcom.

Securities and Exchange Commission and Justice Department investigations found that companies were issuing stock options and then backdating them to a date when the stock price was lower, ensuring a windfall for executives.

Mr. Miller, former chairman and chief executive of AOL, joined Mr. Levinsohn, a former News Corp. executive credited with engineering the $580 million acquisition of social network MySpace, to found Velocity Interactive in December through a merger with ComVentures.