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 dairy company Dean Foods (NYSE: DF) surged 11% on Wednesday after the company's quarterly results and outlook topped Wall Street expectations.

So what: Dean Foods' big fourth-quarter beat -- adjusted EPS of $0.27 versus the consensus of $0.23 -- seems to be easing serious investor concerns over rapidly declining margins. Management has been desperately trying to control expenses amid spiking input costs and weak demand over the past few years, so today's results come as a much-needed turnaround sign.

Now what: Management now sees fiscal 2012 adjusted EPS of $0.87 to $0.95, while analysts were expecting $0.89. "Looking ahead, we are cautiously optimistic as we enter 2012," said CEO Gregg Engles. "[W]e believe our actions to significantly reduce supply chain and overhead costs and simplify the FDD organization have positioned the business to stabilize and compete effectively in a challenging marketplace." Given the company's still-heavy debt load and recent share price run, however, I'd continue to be cautious about buying in.

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