Billionaire investor Kirk Kerkorian said he has added $100 million to his pool of capital for buying shares of Ford, and may borrow as much as $600 million to buy shares, according to a U.S. Securities and Exchange Commission filing, Bloomberg News reported Friday.

Kerkorian now says he may borrow up to $600 million, up from $500 million, from the Bank of America (NYSE: BAC), according to the filing, Bloomberg News reported.

Ford's (NYSE: F) shares fell 40 cents to $6.75 in mid-day Friday trading, amid a broader market sell-off.

Kerkorian's announcement occurred one day after Ford advised analysts and investors that it had abandoned its profitability target for 2009, due to rising steel and gasoline costs, among other factors, The Washington Post reported Friday.

Ford's shares: not overpriced

Independent stock analyst C. Leonard Bauer said Kerkorian's tactic, should he follow-through and increase his 5.5% Ford stake, is daring, but risky. "Let's just put it this way: Kerkorian would not be radically overpaying for Ford at these price levels," Bauer said.

Still, Bauer underscored that the cheapness of Ford's shares should not be confused with less-risk. "Ford remains a high-risk operation. It's done a good job lowering legacy costs, but the fleet remains unacceptable, on a whole," Bauer said. Bauer added that he does not have a rating on nor own shares in Ford.

Bauer said the company "remains in a sort of suspended animation" regarding customer preferences. The public, including the SUV and truck buying segments, want more-efficient vehicles, he said. "Gasoline is approaching $4 per gallon in many regions, and it looks like that's going to be the new floor price, so Ford has to find a way to re-engineer these vehicles or create new ones that are right for this age," Bauer said. "Ford must reclaim some of the higher mpg market to grow."