Updated below: This will send tremors throughout the industry: newspaper giant Knight Ridder‘s largest shareholder, Florida money-management firm Private Capital Management (own about 19 percent of the stock), is urging the newspaper publisher to put itself on the block, citing the poor performance of its stock price.

PCM CEO Bruce Sherman said a sale should be pursued aggressively, “in light of limited revenue growth across the newspaper industry and the difficulties the company has faced in realizing the fair value” for its shareholders, an SEC filing said. The full SEC filing is here

Among the more aggressive efforts that could be pursued at Knight Ridder are a shakeup of the board, a change in management or the acquisition of a majority of the company’s voting shares, PCM said in the letter. It will be a leveraged buyout, if it happens…

After Gannett, Knight Ridder is the second-largest newspaper publisher in the United States and operates the Real Cities Network of local news websites in more than 110 markets nationwide.

AP: The continued erosion convinced PCM Knight Ridder won’t be able to adapt to a media market that is increasingly being driven by the Internet. In his letter, Sherman also cited the company’s “unexceptional” profit margins and a “lack of a nationally read paper capable of being leveraged in the online market.”

Related: Media Executive Interview Series: Hilary Schneider, Senior VP, Knight Ridder