By David Bailey

DETROIT (Reuters) - Billionaire investor Kirk Kerkorian on Friday launched a planned tender offer to add to a Ford (F.N: Quote, Profile, Research) stake he called an "attractive investment," and not one he acquired to influence the automaker.

Just how passive the long-time activist investor in the U.S. auto industry will stay remained unclear.

Kerkorian said through his Tracinda that he may propose business strategies for Ford depending on his evaluation of the automaker's business and other factors, and could acquire more shares after the tender offer.

"We are making our offer because we believe that the current management and leadership at Ford Motor Company and the pending execution of management's turnaround strategy make Ford Motor Company an attractive investment," Tracinda said in a filing with the U.S. Securities and Exchange Commission.

Kerkorian most recently held a nearly 10 percent stake in General Motors (GM.N: Quote, Profile, Research) and made an unsuccessful bid to acquire Chrysler in 2007.

The cash tender offer for 20 million Ford shares is priced at $8.50 and is scheduled to expire at 10 p.m. British time on June 9 unless it is extended, Tracinda said in a statement.

Tracinda on April 28 disclosed it had acquired 100 million shares of Ford at an average price of $6.91 starting April 2 and planned to buy more. The tender offer would raise the stake to about 5.5 percent.

Ford shares closed Friday down 10 cents, or 1.2 percent lower, to $8.10 on the New York Stock Exchange.