Stock Quotes in this Article: CLNE, CVLT, DNDN, FSYS, IPXL, REXX, ZIGO, TNGO

WINDERMERE, Fla. (Stockpickr) -- Professional traders running mutual funds and hedge funds don’t just look at a stock’s price moves; they also track big changes in volume activity. Many times when above average volume moves into equity it precedes a large spike in volatility.

Major moves in volume can signal unusual activity, such as insider buying or selling -- or buying or selling by “superinvestors.”

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Unusual volume can also be a major signal that hedge funds and momentum traders are piling into a stock ahead of a catalyst. These types of traders like to get in well before a large spike, so it’s always a smart move to monitor unusual volume. That said, remember to combine trend and price action with unusual volume. Put them all together to help you decipher the next big trend for any stock.

Let's take a look at several stocks rising on unusual volume today.

Rex Energy

Rex Energy (REXX) is an independent oil and gas company operating in the Appalachian Basin and the Illinois Basin. The stock is trading up 5.5% at $9.98 in recent trading.

Today’s Volume: 2.86

Average Volume: 999,994

Volume % Change: 365%

Shares of REXX are soaring today after the company announced a public offering of 7 million shares of common stock at a price of $9.25 per share.

From a technical standpoint, REXX is bouncing big off its 52-week low of $9.29 today with monster volume. As long as this stock can manage to close near its highs of the day, then traders should look for continued upside back towards some near-term overhead resistance levels at $11 to $11.60 a share.

Clean Energy Fuels

Clean Energy Fuels (CLNE), together with its wholly owned subsidiaries, is engaged in the business of selling natural gas fueling solutions to its customers, primarily in the U.S. and Canada. The stock is trading up 3.5% at $15.49 in recent trading.

Today’s Volume: 2.4 million

Average Volume: 1 million

Volume % Change: 283%

Shares of CLNE are jumping to the upside today after the company said it signed a strategic joint marketing and fueling agreement with Navistar International (NAV).

From a technical standpoint, CLNE has started to trigger a breakout trade today now that the stock has cleared some near-term overhead resistance at $15.40 with monster volume.

Market players should continue to look for long-biased trades in CLNE as long as the stock can continue to trend above $14.47 and $15.40. Some potential targets if those breakout levels hold are $16.50 to $17.50 in the very near future.

Impax Laboratories

Impax Laboratories (IPXL) is a technology-based, specialty pharmaceutical company applying formulation and development expertise, as well as its drug delivery technology, to the development, manufacture and marketing of bioequivalent pharmaceutical products. This stock is trading up 6.7% at $20.16 in recent trading.

Today’s Volume: 858,000

Average Volume: 534,669

Volume % Change: 137%

Shares of IPXL are soaring today after the company announced it obtained the U.S. rights to AstraZeneca PLC’s migraine headache drug Zomig.

From a technical standpoint, IPXL bounced big right off its 50-day moving average today at $19.41, and it briefly traded above its 200-day moving average of $20.64 on big volume.

Market players should now watch for the next big breakout trade to trigger in IPXL once this stock moves above $21.68 to $22.07 with volume. Look for volume that’s near or above 534,669 if we that breakout soon.

Impax shows up on recent lists of 8 Pharma Stocks to Watch and 5 Bargain Biotech Stocks.

Tangoe

Tangoe (TNGO) is a global provider of on-demand communications lifecycle management, software and related services to a range of enterprises, including large and medium-sized businesses, and other organizations. The stock is trading up 3.5% at $14.97 in recent trading.

Today’s Volume: 409,000

Average Volume: 137,095

Volume % Change: 285%

From a technical standpoint, TNGO is bouncing big right off its 50-day moving average at $14.55 today with massive volume. Market players should continue to look for long biased trades in TNGO as the stock approaches a major breakout above $16.14 and then $16.41.

If those levels get taken out with volume soon, then TNGO will be trading in all-time high territory, which is very bullish price action. Look for volume on any move over the breakout levels that are well above 137,095 shares.

Tangoe shows up on a list of the 5 Best IPOs of 2011.

CommVault Systems

CommVault Systems (CVLT) is a provider of data and information management software applications and related services. This stock is trading up 7.6% at $50.59 in recent trading.

Today’s Volume: 1.5 million

Average Volume: 537,848

Volume % Change: 324%

Shares of CVLT are soaring today after the company said it beat Wall Street estimates on the top and bottom lines for its third quarter ended on Dec 31. Revenue for the quarter rose 24% to $103.6 million versus Wall Street estimates of $100 million.

From a technical standpoint, CVLT is quickly approaching a major breakout trade today now that the stock is trending right below its all-time high of $50.90.

Traders should now look for a sustained high-volume move and close over $50.90 to signal that CVLT wants to break out and spike higher. Look for volume that’s near or above 537,848 on any move over $50.90.

At last check, volume today is very strong and the stock has printed a high of $50.87.

CommVault shows up on a recent list of 10 Stocks of Top-Performing Funds in 2012 and was featured in "5 High-PEG Stocks to Stay Away From."

Zygo

Zygo (ZIGO) designs, develops, and manufactures ultra-high precision measurement solutions. This stock is trading up 3.5% at $18.32 in recent trading.

Today’s Volume: 91,000

Average Volume: 69,797

Volume % Change: 107%

From a technical standpoint, ZIGO is getting close to trigging a major breakout today now that the stock is close to taking out some near-term overhead resistance levels.

Traders should continue to look for long biased trades in ZIGO if this stock can manage to clear $18.23 to $18.65 with big volume. Look for volume on any future move over $18.23 to $18.65 that’s well above 69,797 shares. If we get that action soon, look for ZIGO to pop big since the stock will then be trading at levels not seen since 2006.

Dendreon

Dendreon (DNDN) is a biotechnology company focused on the discovery, development and commercialization of therapeutics that may improve cancer treatment options for patients. This stock is trading up 5.9% at $14.39 in recent trading.

Today’s Volume: 11.5 million

Average Volume: 9 million

Volume % Change: 113%

Shares of DNDN are ripping higher today after the company announced it hired former Eli Lilly (LLY) and Savient Pharmaceuticals (SVNT) executive, John H. Johnson, as its new president and CEO.

From a technical standpoint, DNDN are quickly approaching a big breakout today with the stock trading right below a major overhead resistance level at $15.21. At last check, the volume for DNDN is extremely strong and the stock has printed a daily high of $14.71.

Market players should continue to look for long biased trades in DNDN if it can manage to break out over $15.21 with volume in the near future.

Fuel Systems Solutions

Fuel Systems Solutions (FSYS) designs, manufactures and supplies alternative fuel components and systems for use in the transportation and industrial markets. This stock is trading up 10.9% at $23.13 in recent trading.

Today’s Volume: 444,000

Average Volume: 235,603

Volume % Change: 190%

From a technical standpoint, FSYS is gaping up big today on heavy volume back above its 200-day moving average of $21.32.

Traders should now look for long biased trades in FSYS as the stock approaches its next big breakout over $24.14. A high-volume move above that level should setup FSYS to re-test $24.49 or potentially much higher, since $24.49 is the last major overhead resistance until $30.

To see more stocks rising on unusual volume, check out the Stocks Rising On Unusual Volume portfolio on Stockpickr.

-- Written by Roberto Pedone in Winderemere, Fla.

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At the time of publication, author had no positions in stocks mentioned.

Roberto Pedone, based out of Windermere, Fla., is an independent trader who focuses on stocks, options, futures, commodities and currencies. He is also an outside contributor to Beconequity.com and maintains the website Maddmoney.net, which he sold to Blue Wave Advisors in 2008. Roberto studied International Business at The Milwaukee School of Engineering, and he spent a year overseas studying business in Lubeck, Germany.