Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of car rental company Dollar Thrifty Automotive Group (NYSE: DTG) jumped 13% today after Hertz Global (NYSE: HTZ) made another bid for the company.

So what: The new offer from Hertz is for a total of $72 per share consisting of $57.60 in cash and 0.8546 shares of Hertz stock. That’s more than a 30% jump from $43.60 per share in cash and 0.6366 shares of Hertz stock offered last September.

Now what: The market still doesn’t think that’s enough, with Dollar Thrifty shares jumping to $78.80 as I am writing. That might be right considering Avis Budget Group (Nasdaq: CAR) is still in the mix and this bidding war might just be heating up. I would be cautious here because Avis could walk away from the bidding, leaving $72 as the best offer. The upside potential is there, but it isn’t attractive enough to bet the farm.

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