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: St. Joe Company (NYSE: JOE) dropped 12% in intraday trading today after news broke over the weekend that the company and its chairman are subjects of a formal Securities and Exchange Commission probe.

So what: There's nothing like a whiff of accounting scandal to scare investors and this one is a stink bomb. An SEC filing made after the markets closed on Friday disclosed the probe, which covers a variety of matters ... including securities-law anti-fraud provisions for corporate officers and board members, internal controls, and financial reports.

Now what: When it rains on northern Florida's largest landowner, it pours. The company revealed last January that the SEC is conducting an informal investigation into its real estate impairment practices, a big ticket item for a real estate development company. That was followed on June 24 by a "related order of private investigation." Investors should take no comfort from what may have piqued the SEC's interest: Greenlight Capital's David Einhorn, famous for an early call on Lehman Brothers failure, accused St. Joe in October of overvaluing its real estate post-crash.

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Fool contributor Cindy Johnson does not own shares of any company named above. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.