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 cyber-security specialist FireEye, Inc. (NASDAQ:FEYE) jumped more than 10% early Tuesday, then settled to close up around 5% after an analyst reiterated his "buy" rating on the stock ahead of a post-secondary stock offering lock-up expiration.

So what: According to FireEye's Form S-1 filed last month, just over 82.2 million previously restricted shares will become eligible for sale tomorrow upon the expiration of lock-up agreements entered into in connection with FireEye's secondary stock offering in March. 

However, Nomura Securities' Rick Sherlund suggests much of FireEye's weakness is owed to a "rotation out of the high valuation momentum names," and that the stock "may benefit from ... getting past the ... lock-up expiration that has dampened investor sentiment." In addition, Sherlund thinks FireEye can look forward to investor presentations at upcoming conferences "with a strong fundamental story to articulate," and that its already-impressive growth is likely to build the rest of this year as its products gain traction.

Now what: FireEye definitely fits the bill for a "high valuation momentum" name: Nobody expects it to turn a profit anytime soon, and FireEye shares currently trade at a lofty 20 times trailing 12-month sales. This in mind, the timing of Sherlund's call is no coincidence, especially considering other companies' recent lock-up expirations have resulted in steep -- albeit temporary -- pullbacks as the market frets about potential insider selling.

In any case, while I agree investors would do well to look past the expiration and focus on FireEye's long-term story, I'm still not personally inclined to dive into FireEye shares just yet.