It's about time! An insider actually bought shares of Crocs (Nasdaq: CROX)! You probably know that insiders were selling shares back when the stock was still hot, but the lack of insider buying until now couldn't have been very comforting for shareholders.

The buyer in question is Michael Marks, a member of Crocs' board of directors as well as a partner at private-equity firm Kohlberg, Kravis, Roberts. He's the former CEO of Flextronics (Nasdaq: FLEX), and according to Crocs' proxy statement last year, he serves on that board as chairman and also sits on the boards of SanDisk (Nasdaq: SNDK), Schlumberger (NYSE: SLB), and Sun Microsystems (Nasdaq: JAVA). Busy guy.

Anyway, Marks purchased 250,000 shares of Crocs earlier this week. That's a $5 million investment -- not exactly chump change. He now owns 3.6% of the company's shares; he had held 3.4%, according to last year's proxy statement.

A peek at the company's insider sales (which you can find at Yahoo! Finance) shows that many insiders sold Crocs shares late last year, when the stock was trading at much higher levels. In the past three months, the stock has fallen by an astounding 51%, but those insiders -- including company executives -- made out like bandits before the bloodbath. The stock's 52-week high was $75.21.

With inventory piling up recently, it's been easy to suppose that demand for Crocs' brightly colored shoes is dwindling. That's always been the bear case for Crocs, and we all know the fate of other faddish momentum stocks, like Heelys (Nasdaq: HLYS) and Jones Soda (Nasdaq: JSDA).

Crocs is starting to look inexpensive, with a price-to-earnings ratio of 10 and a PEG ratio of 0.32. That may have influenced Marks' decision to up his stake.

On the other hand, to believe that Crocs is cheap at these levels also requires conviction that Crocs shoes truly aren't a fad and that analysts' estimates are correct about what kind of growth Crocs can deliver for the long term.

As a matter of principle, though, Marks' move looks heartening. It's nice to see a board member putting his own money on the line. When you have your own financial stake, you're expressing your conviction about long-term prospects.

Shareholders surely hope that Crocs' management feels the same way.

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Alyce Lomax does not own shares of any of the companies mentioned. The Fool has a disclosure policy.