I bet you want me to tell you why Finisar's (Nasdaq: FNSR) share price was cut off at the kneecaps yesterday. The optical networking component maker's report really wasn't bad. The product is used by information storage companies like EMC (NYSE: EMC).

Sorry. Can't help you. But I'll try anyway.

Finisar revenue increased about 5% year over year from approximately $107 million to $112 million. However, the company's non-GAAP earnings per share dropped from $0.04 to $0.02. Nevertheless, Finisar met analyst expectations of $0.02 in adjusted earnings per share. Like Google and Berkshire Hathaway, Finisar doesn't play the earnings guidance game, so that's not the culprit. The revenue forecast it does provide was positive, and the executives sounded downright upbeat in the conference call, talking about growth opportunities like data center virtualization. You can't even blame the drop on analyst downgrades -- there weren't any.

How about sudden competitive pressures, then? Nope -- no major optical networking news from JDS Uniphase (Nasdaq: JDSU), Cisco (Nasdaq: CSCO), or Brocade (Nasdaq: BRCD), and all of those stocks traded markedly sideways yesterday.

Given the stock chart yesterday, it seems likely that a major shareholder unloaded some stock on the open market. Fidelity Investments owned 13.4% of the outstanding stock at the end of 2007, and T. Rowe Price (Nasdaq: TROW) held 9.1%, putting them in the lineup of usual suspects. Price doesn't seem too hard-pressed for liquidity these days, but $18 billion flowed out of privately held Fidelity's mutual funds last year. Maybe that's the backbreaker.

In the end, the exact reason doesn't really matter. The facts we have in front of us say that there's nothing wrong with Finisar's business, and we really shouldn't look this spurious and curious bargain price in the mouth. The discount moment will pass while we wait and ponder the cosmic relevance of intraday trading volume spikes on no relevant news. Leave the rocket science to the rocket scientists, and just ride the rocket.

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