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 OPNET Technologies (Nasdaq: OPNT) have plunged today by as much as 15% after the company posted preliminary earnings yesterday.

So what: It's not an official earnings release for the just-closed quarter, but it's pretty close. The company's preliminary estimates show revenue between $44.4 million and $44.6 million, with non-GAAP earnings per share to be between $0.20 and $0.21. Analysts were expecting $47 million in revenue and $0.26 per share in profit.

Now what: CEO Marc Cohen said some of the shortfall was related to "last-minute purchasing delays" associated with $2.4 million in deals, but he expects those deals to close by the end of this month. The company believes the contributing factors here are isolated and don't represent its overall business strength.

Interested in more info on OPNET Technologies? Add it to your watchlist by clicking here.

Fool contributor Evan Niu holds no position in any company mentioned. Click here to see his holdings and a short bio. The Motley Fool has a disclosure policy.
We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. Try any of our Foolish newsletter services free for 30 days.