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 bio-defense specialist SIGA Technologies (Nasdaq: SIGA) surged as high as 26% in intraday trading Tuesday after a unit of the U.S. Department of Health and Human Services advised it that it is issuing a new request for proposal to procure 1.7 million courses of a smallpox antiviral.

So what: The contract also includes an option to procure up to 12 million additional courses and naturally represents a huge opportunity for the small cap SIGA. Wall Street analyst Wedbush Securities even recommended that investors aggressively buy shares on the attractive odds that the reissued RFP will, indeed, lead to a contract win for SIGA.

Now what: Fools know never to buy anything on the expectation of large short-term profits. While SIGA Chairman and CEO Dr. Eric Rose believes SIGA is "well positioned to meet the Government's needs," the company is still simply too young and unprofitable for most investors. With SIGA's shares having now more than doubled over the past year and trading at steep price-to-sales ratio of 27, the decision to steer clear is that much easier.

Interested in more info on SIGA? Add it to your watchlist.

Fool contributor Brian Pacampara owns no position in any of the companies mentioned. Try any of our Foolish newsletter services free for 30 days.

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