WINDERMERE, Fla. ( Stockpickr) -- Professional traders who run 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 a several stocks rising on unusual volume today. They are all recording volume in midday trading that is already at least 50% above their average trading volume for a full day.

Fusion-IO

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Fusion-IO ( FIO) is a provider of data-centric computing solutions: a combination of hardware and software that places data closer to processing. The stock is trading up 2.8% at $38.08 in recent trading.

Today's Volume: 946,000

Average Volume: 751,567

Volume % Change: 224%

From a technical standpoint, this stock triggered a major breakout recently when it moved above some past overhead resistance at $36.98 on solid volume.

Traders should now watch for the next big breakout to trigger if FIO can push above $39.11 with solid volume. A move above that level should set this stock up for another big push higher.

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Pharmasset

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Pharmasset ( VRUS) is a clinical-stage pharmaceutical company focused on discovering, developing, and commercializing novel drugs to treat viral infections. The stock is trading up 1.6% at $70.02 in recent trading.

Today's Volume: 2,160,000

Average Volume: 1,218,880

Volume % Change: 231%

This stock is moving higher today after the company said its experimental drug for treating hepatitis C cured all 40 of the patients in a study.

From a technical standpoint, this stock is still trading below its 50-day moving average of $75.20 a share. Traders should avoid this stock until it can clear that key technical level on solid volume.

Pharmasset shows up on a recent list of 8 Health Care Stocks to Buy.

HMS Holdings

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HMS Holdings ( HMSY) provides a variety of cost containment, coordination of benefits and program integrity services for government and private health care payers and sponsors. The stock is trading up 15% at $28.91 in recent trading.

Today's Volume: 1,322,000

Average Volume: 665,038

Volume % Change: 306%

Shares of HMS Holdings are soaring today after the company announced it plans to acquire privately held HealthDataInsights for around $400 million.

From a technical standpoint, this stock is challenging a big breakout here with shares starting to move above some past overhead resistance at $28.27 a share on solid volume.

>>Stocks Hitting New 52-Week Highs As long as this stock can sustain a move and close above that level, then traders should look for a continued trend higher for HMSY. Any high-volume moves back below $28.27 would indicate a possible failed breakout, so watch that level closely.

Amgen

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Amgen ( AMGN) is an independent biotechnology medicines company that discovers, develops, manufactures and markets medicines for grievous illnesses. It focuses on human therapeutics and concentrates on medicines based on advances in cellular and molecular biology. The stock is trading up 4.4% at $57.63 in recent trading.

Today's Volume: 8,900,000

Average Volume: 6.783,010

Volume % Change: 193%

This stock is spiking higher today after the company said it plans to buy back up to $5 billion worth of its stock in a modified Dutch auction tender offer.

From a technical standpoint, this stock is gapping above its 50-day moving average of $56.06 today on solid volume. Traders should look to play the next big breakout for AMGN if the stock can manage to move above some past overhead resistance at $59.05 on strong volume. A high volume move above $59.09 should set this stock up to re-test its 52-week high of $61.53.

Amgen is one of the top-yielding drug stocks and one of TheStreet Ratings' top-rated biotech stocks.

Rosetta Resources

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Rosetta Resources ( ROSE) is an independent exploration and production company engaged in the exploration, development, production and acquisition of onshore oil and gas resources in the U.S. The stock is trading up 2.77% at $46.80 in recent trading

Today's Volume: 1,339,000

Average Volume: 1,234,420

Volume % Change: 149%

This stock is soaring today after the company posted a third quarter profit that beat Wall Street expectations, helped by higher production from its Eagle Ford Shale assets in south Texas.

From a technical standpoint, this stock briefly took out some big overhead resistance levels at $47 to $48.50 a share in intraday trading. After moving above those resistance levels, the stock failed to move back above the next significant resistance at $49.60.

Traders should now watch for a sustained move and close above $49.60 on strong volume. If we get that move either today or in the coming days or weeks, then target a run back towards $54 to $58 a share.

>>5 Oil & Gas Stocks to Take Advantage Of

Coeur d'Alene Mines

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Coeur d'Alene Mines ( CDE) is a primary silver producer with gold production and has assets located in the U.S., Mexico, Bolivia, Argentina and Australia. The stock is trading up 6.8% at $29.13 in recent trading.

Today's Volume: 2,144,000

Average Volume: 2,276,370

Volume % Change: 167%

This stock is jumping higher today after the company reported a $31.1 million third-quarter profit, as gold and silver sales more than doubled on increases in prices and production.

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From a technical standpoint, this stock is breaking out today back above its 50-day moving average of $25.22 on heavy volume, which is bullish. The stock has now also taken out some past overhead resistance at $28.70, and it's just a few points off its next significant resistance level at $30.99.

Traders should look to buy the next high volume breakout over $31, since it should set the stock up to make a run at $33 to $37.50.

CDE shows up on a recent list of 3 Commodities Stocks to Buy Now.

Rubicon Technology

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Rubicon Technology ( RBCN) is an electronic materials provider that develops, manufactures and sells monocrystalline sapphire and other crystalline products for light-emitting diodes (LEDs), radio frequency integrated circuits, blue laser diodes, optoelectronics and other optical applications. The stock is trading up 7.2% at $12.65 in recent trading.

Today's Volume: 513,000

Average Volume: 517,068

Volume % Change: 135%

This stock is spiking big today after Lazard Capital upgraded it based off of expectations for wafer pricing stabilization in the second half of 2012. Lazard issued a price target of $15 a share.

From a technical standpoint, this stock is breaking out above some past overhead resistance at $11.80 a share on big volume. This stock also just cleared its 50-day moving average of $11.15 on monster volume on Friday. Rubicon is set to report earnings on Tuesday after the market close.

Since this stock has a huge short interest at over 30%, traders should look for continued upside if they report bullish earnings.

-- 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.
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.