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 cereal specialist Ralcorp Holdings (NYSE: RAH) sank 10% on Wednesday after ConAgra (NYSE: CAG) gave it a deadline to start negotiations regarding its $5.2 billion takeover offer.

So what: If Ralcorp doesn't at least begin some "constructive dialogue" about the proposed deal by 5 p.m. on Monday, ConAgra said it will rescind its offer. Ralcorp has already rejected several takeover bids by its larger counterpart, but according to ConAgra, the $94-per-share offer represents an "attractive multiple compared to many other private label and branded food transactions."

Now what: I'd consider pouncing on today's plunge. Ralcorp shares are already trading at about a 20% discount to ConAgra's offer, so I wouldn't expect the stock to suffer too much more if Ralcorp fails to meet the Monday deadline. And given that its forward P/E is now in line with rivals like General Mills (NYSE: GIS) and Kraft (NYSE: KFT), Ralcorp seems like a relatively solid bet, as well.

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Fool contributor Brian Pacampara owns no position in any of the companies mentioned. Try any of our Foolish newsletter services free for 30 days.

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