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 transaction-management platform provider Synchronoss Technologies (Nasdaq: SNCR) slid as much as 11% on the news that company founder James McCormick had adopted a plan to sell some of his stock holdings.

So what: McCormick entered a 10b5-1 plan, which lets an insider prearrange a schedule to sell stock over a certain period of time. The plan allows insiders to spread their transactions out over time so they don't flood the market all at once, and eliminates the risk of being blocked from transacting if they receive material, non-public information. Once one of these plans is set, the insider doesn't have any further say in the timing of the transactions. If all the sales are completed, McCormick's plan would dispose of 15% of his holdings.

Now what: Investors often favor insider ownership as a key piece in the investing puzzle. For that reason, when insiders are buying, investors get excited, and when insiders are selling, they may jump ship themselves. All else equal, I prefer more insider ownership to less, but it's relatively low on my list of must-haves. It might make sense for an insider to sell shares for many reasons: to diversify their assets, buy a vacation home, light $100 bills on fire because they're so filthy rich ... you get the picture. In McCormick's case, as the proud owner of the largest stake in Synchronoss, he'll still be a very significant shareholder once the selling is completed. As such, it seems to me that the market may be overreacting a bit to this news.

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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 assures you no Wookiees were harmed in the making of this article.