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 Infinera (INFN -1.05%) popped by as much as 12% today after an insider purchased shares.

So what: CEO Thomas Fallon filed an SEC Form 4 late Friday after market close, disclosing several purchase transactions from last week in a vote of confidence in the company's prospects. Last week, Fallon exercised employee stock options to purchase 100,000 shares at $2 per share. These options didn't expire until 2016, so Fallon exercised well before he had to.

Now what: Even more bullish is that Fallon also made an additional open market purchase of 50,000 shares at prices ranging from $4.44 to $4.60. After everything was said and done, Fallon's open market trade totaled a little over $220,000 invested, in addition to the option exercise and his existing holdings. Among all his various trusts, he beneficially owns nearly 850,000 shares, so the purchase last week was a notable addition to his stake in the company.

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