Shares in Gemstar-TV Guide International Inc. plunged nearly 18 percent Friday as investors showed discontent with a $2.8 billion acquisition of the media company by Macrovision Corp.

The cash and stock deal, announced before the market opened, values shares in Los Angeles-based Gemstar at $6.35 in cash or 0.255 of a share of common stock in a new holding company that will own both Gemstar-TV Guide and Macrovision.

The price is a 6.2 percent premium on Gemstar’s closing price Thursday and 25 percent premium on Gemstar’s shares before it announced it was exploring strategic alternatives on July 9. The cash component of the deal will not exceed $1.55 billion, Santa Clara-based Macrovision said.

Macrovision’s main business develops technology to prevent unauthorized copying and viewing of video, music and other content. The acquisition is a move by the company to take Gemstar’s proprietary technology for TV listings and incorporate it into a network that allows consumers to call up TV show information, view personal photos or access music libraries on a various electronic devices.

Macrovision’s Chief Executive Fred Amoroso did not disclose plans for Gemstar’s flagship TV Guide print operations, saying he would need time to understand that business before making decisions. The magazine has struggled with falling circulation and advertising revenue as viewers increasingly access programming data through their TV sets or online.

Gemstar’s borad has unanimously approved the transaction, which is expected to close by early second quarter 2008. Rupert Murdoch’s News Corp., which owns about 41 percent of Gemstar-TV Guide, has agreed to vote in favor of the deal as well, Gemstar said.

Amoroso will serve as president and chief executive of the new company and the new board will include four directors chosen by Macrovision, and three by Gemstar-TV Guide. Gemstar-TV Guide CEO Rich Battista will leave when the deal closes.

Shares in Gemstar plummeted more than 16 percent to $5.01 in early trading Friday and shares in Macrovision dropped 24 percent to $6.29.