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 boutique investment bank Greenhill (NYSE: GHL) were shelled in trading today, falling as much as 12% after the company announced fourth-quarter results.

So what: It was a pretty ugly quarter for Greenhill. Analysts were looking for $0.52 per share in profit during the quarter, and the actual results limped in at $0.06 per share. Unlike bulge-bracket competitors like Goldman Sachs and JPMorgan Chase, Greenhill doesn't have a massive trading arm to juice results and instead relies primarily on advisory fees. And, in particular, the firm has a strong presence in Europe, which has been particularly quiet on the deal-making front lately thanks to the debt crisis. Greenhill's advisory fees in the fourth quarter fell 10% from last year.

Making it all even worse, the company has been adding to its headcount, which bumped up compensation expenses. For the fourth quarter, compensation expenses gobbled up an amazing 73% of the company's revenue.

Now what: The financial advisory business is nothing if not volatile, and it's not all that surprising to see the occasional drastic swing in results. Along with Lazard (NYSE: LAZ), Greenhill is by far one of my favorite investment banks, and I see little reason to doubt that it will return to a better form in the coming quarters. As for buying the stock, however, I'd want to see the price come down considerably before I put my money on the line.

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Fool contributor Matt Koppenheffer does not own shares of any of the companies mentioned. You can check out what Matt is keeping an eye on by visiting his CAPS portfolio, or you can follow Matt on Twitter @KoppTheFool or on his RSS feed. The Fool's disclosure policy prefers dividends over a sharp stick in the eye.