Why Affymetrix Inc. Shares Popped

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 genetic testing instrument maker Affymetrix  climbed 11% today after its fourth-quarter sales outlook impressed Wall Street.

So what: The stock has rocketed over the past six month on optimism over stabilizing demand, and today's preliminary fourth-quarter report only reinforces those good vibes. In fact, Affymetrix's projected revenue represents about 8% growth over the year-ago period, suggesting that its competitive position is strengthening as well.  

Now what: Management now expects fourth-quarter revenue of roughly $91 million, which includes a one-time $5.3 million licensing payment from a diagnostic partner.

"In 2013 we executed effectively against our three phase strategic plan and we exited the year as a much stronger Company," said President and CEO Dr. Frank Witney. "Over the last 12 months we improved our business's performance, significantly reduced our senior debt and increased our overall cash balance."

Of course, with Affymetrix shares now up a whopping 130% since August and trading at a forward P/E of 60, much of that improvement might already be baked well into the valuation.