UPDATE 1-Pershing raises stake in Landry's, cool on deal

* Pershing Square raises stake for second time in a week

* Fund now has about 25 pct of Landry's outstanding shares

* Landry's share price up 25 pct since stake revealed

BOSTON, Nov 20 (Reuters) - Hedge fund Pershing Square Capital Management said on Friday it had increased its stake in Landry's Restaurants Inc LNY.N for the second time in a week, underscoring its intent to block an effort to take the company private.

The New York-based hedge fund now owns about 25 percent of the outstanding shares of the nation's second-largest seafood restaurant operator.

Run by activist investor William Ackman, the fund said in a regulatory filing that it had increased its total economic exposure to 4 million shares from the 3.8 million shares it reported on Nov. 13.

It reported that it now has an additional economic exposure of roughly 2.4 million shares under certain cash-settled total return swaps. The swaps will expire on dates ranging from June 30, 2011 through December 9, 2011.

By building a position as quickly as possible, Pershing's Ackman is pitting himself squarely against Landry's CEO Tilman Fertitta, who owns 55.1 percent of the company and has been trying to take the company private for two years.

A week ago, Ackman said he would oppose Fertitta's plan to buy out minority shareholders for $14.75 a share.

Analysts said Pershing Square's moves could signal the hedge fund's intent to try and get a higher price, possibly twice what Fertitta offered, or to stick around and become involved in the management.

Ackman cemented his reputation as an activist investor by prodding fast food restaurants, including Wendy's/Arby's Group Inc WEN.N and McDonald's Corp (MCD.N), to change and he has tried to block a deal at human resources company Ceridian. This spring he waged a high profile proxy fight with retailer Target (TGT.N).

Since Pershing Square announced its position a week ago, Landry's share price has climbed 25 percent and closed Friday trading at $19.51. (Reporting by Svea Herbst-Bayliss; Editing by Tim Dobbyn)