Stock Quotes in this Article: SSYS, AMBA, QLYS

MADISON, Wis. (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. Often when above-average volume moves into an 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.

With that in mind, let's take a look at several stocks rising on unusual volume today.

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Qualys

Qualys (QLYS) providers cloud security and compliance solutions that enable organizations to identify security risks to their IT infrastructures. This stock is trading up 9.7% at $12.36 in recent trading.

Today's Volume: 185,000

Average Volume: 99,803

Volume % Change: 195%

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From a technical perspective, QLYS is exploding higher here back above its 50-day moving average at $11.70 with above-average volume. This move has broken a recent downtrend for shares of QLYS, which took the stock from $16.38 to $10.22. Shares of QLYS are now quickly approaching a near-term breakout trade. That trade will hit if QLYS manages to clear some near-term overhead resistance levels at $12.49 to $13.05 with high volume.

Traders should now look for long-biased trades in QLYS as long as it's trending above $12 or above its 50-day at $11.70 and then once it sustains a move or close above those breakout levels with volume that hits near or above 99,803 shares. If that breakout triggers soon, then QLYS will set up to re-test or possibly take out its next major overhead resistance levels at $13.44 to $14. Any high-volume move above $14 will then put $15 to $16 into range for shares of QLYS.

Ambarella

Ambarella (AMBA) is a developer of semiconductor processing solutions for video that enable high-definition video capture, sharing and display. This stock is trading up 6.8% at $15.31 in recent trading.

Today's Volume: 1.48 million

Average Volume: 431,217

Volume % Change: 361%

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From a technical perspective, AMBA is gapping higher here and breaking out above some near-term overhead resistance at $15.09 with heavy upside volume. This move is quickly pushing shares of AMBA within range of triggering a major breakout trade. That trade will hit if AMBA manages to take out its 52-week high at $16 with high volume.

Traders should now look for long-biased trades in AMBA as long as it's trending above $15.09 or above today's low of $14.64 and then once it sustains a move or close above $16 with volume that hits near or above 431,217 shares. If that breakout triggers soon, then AMBA will set up to enter new 52-week-high territory, which is bullish technical price action. Some possible upside targets off that breakout are $18 to $20. 

Stratasys

Stratasys (SSYS) is a global provider of additive manufacturing, or AM, solutions for the creation of parts used in the processes of designing and manufacturing products and for the direct manufacture of end parts. This stock is trading up 2.7% at $85.71 in recent trading.

Today's Volume: 1.69 million

Average Volume: 778,527

Volume % Change: 277%

Shares of SSYS are moving modestly higher here after the company posted a loss in its first quarter mostly due to costs related to its acquisition of Israeli rival Objet. Its adjusted results topped Wall Street's forecasts.

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From a technical perspective, SSYS is bouncing higher here right off some near-term support at $80 with above-average volume. This stock has been uptrending strong for the last two months, with shares soaring higher from its low of $60.20 to its recent high of $86.97. During that uptrend, shares of SSYS have been consistently making higher lows and higher highs, which is bullish technical price action. That move has now pushed shares of SSYS within range of triggering a major breakout trade. That trade will hit if SSYS manages to take out some near-term overhead resistance at $86.97 with high volume.

Traders should now look for long-biased trades in SSYS as long as it's trending above $84 or $85, and then once it sustains a move or close above $86.97 with volume that hits near or above 778,527 shares. If that breakout triggers soon, then SSYS will set up to re-test or possibly take out its next major overhead resistance levels at $90 to $92.30. Any high-volume move above $92.30 would then push shares of SSYS into new 52-weeek-high territory, which would give it a chance at tagging $100 in the near future.

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

-- Written by Roberto Pedone in Madison, Wis.

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

Roberto Pedone, based out of Madison, Wis., is an independent trader who focuses on technical analysis for small- and large-cap stocks, options, futures, commodities and currencies. Roberto studied international business at the Milwaukee School of Engineering, and he spent a year overseas studying business in Lubeck, Germany. His work has appeared on financial outlets including CNBC.com and Forbes.com. You can follow Pedone on Twitter at www.twitter.com/zerosum24 or @zerosum24.