Billionaire Kirk Kerkorian is back at it.

His Tracinda Corp. investment firm says it intends to tender a cash offer to purchase up to 20 million shares of Ford Motor Co. common stock at $8.50 a share. Tracinda began buying Ford shares April 2, and currently holds 4.7% of the auto maker’s outstanding stock.

The move is the latest attempt by Kerkorian to take a large stake in a U.S.-based auto maker.

Last year, Tracinda made an unsuccessful $4.5 billion bid to acquire Chrysler Group from the former DaimlerChrysler AG, and in 2006 the investment firm dumped its 10% stake in General Motors Corp. after attempts to create a 3-way hookup with Nissan Motor Co. Ltd. and Renault SA failed.

Should Tracinda move forward with its latest effort, its stake in Ford would increase to 5.6%. Its offer represents a 13.3% premium over Ford’s closing price on April 25, Tracinda says.

Unlike Chrysler and GM, there is little chance Tracinda could gain control of the Dearborn, MI-based auto maker – unless it drew backing from the Ford family, which holds 70 million shares of “Class B” stock and controls 40% of the voting power.

Tracinda in a statement says its interest in Ford is due to the auto maker’s performance during difficult economic conditions.

Last week, Ford reported first-quarter net income of $100 million, up from a net loss of $282 million in like-2007.

“Tracinda believes that Ford management under the leadership of CEO Alan Mulally will continue to show significant improvements in its results going forward,” the investment firm says.

However, Kerkorian’s recent track record with the industry is prompting speculation over the billionaire’s intended endgame.

Himanshu Patel, an analyst at JP Morgan Securities Inc. says in a research note Tracinda’s motivations are “far from clear at this stage,” but suggests Kerkorian eventually will push for a Ford alliance with Renault-Nissan.

“We think Ford management, under Alan Mulally, is probably open-minded to such an agreement,” Patel says, “particularly if/when Ford’s North American Free Trade Agreement operations are deemed to have stabilized. We sense that Mulally’s relationship with Kerkorian is, at least for now, fairly cooperative.”

In order for a merger to occur, however, the Ford family would have to relinquish some or all of its voting control, Patel notes.

“Historically, we think the Ford family would have been highly reluctant to do so, but with the value of their Ford shares now significantly lower than a few years ago, we think the family’s desire to maintain voting control at all cost is now considerably lower.

In a statement, Ford President and CEO Alan Mulally downplays the impact of Kerkorian’s overture, calling it a vote of confidence in the auto maker’s ongoing restructuring strategy.

“We welcome confidence in Ford and the progress we are making on our transformation plan,” Mulally says. “Any investor can purchase Ford shares, which are sold in the open market. The Ford team remains focused on executing our plan to transform Ford into a lean global enterprise delivering profitable growth to all.”

Patel says Ford is drawing interest from Kerkorian due to its liquidity and its focus on fewer brands. The auto maker recently announced a deal to sell its Jaguar Cars and Land Rover subsidiaries to India’s Tata Motors Ltd.

Ford shares rose 67 cents, or 8.8%, to $8.17 in morning trading.