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.

With that in mind, let's take a look at

several stocks rising on unusual volume today

.

Super Micro Computer

Super Micro Computer

(SMCI) - Get SUPER MICRO COMPUTER, INC. Report

develops and provides server solutions based upon a modular and open-standard architecture. This stock is trading up 2.5% at $18.27 in recent trading.

Today's Volume: 295,000

Average Volume: 130,784

Volume % Change: 375%

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From a technical perspective, SMCI is spiking higher today on heavy volume, and this stock has started to trigger a breakout trade with shares trending above some near-term overhead resistance at $17.80 to $17.85.

Market players should now look for long-biased trades off the next major breakout for SMCI. That trade will trigger once SMCI takes out $19.30 to $19.55 with high-volume. Look for a sustained move or close over those levels on volume that hits near or well above 130,784 shares.

Fortinet

Fortinet

(FTNT) - Get Fortinet, Inc. (FTNT) Report

is a provider of network security appliances and Unified Threat Management network security solutions to enterprises, service providers and government entities worldwide. This stock is trading up 3.2% at $26.57 in recent trading.

Today's Volume: 2.6 million

Average Volume: 2 million

Volume % Change: 211%

Shares of FTNT are ripping higher today after the company beat Wall Street expectations on revenues and met expectations on earnings per share. First-quarter net income rose to $14.2 million, or 9 cents per share, from $13.6 million, or 8 cents per share, a year ago.

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From a technical perspective, FTNT is moving back above its 50-day moving average today at $27.07 with heavy volume. This move is quickly pushing FTNT within range of a near-term breakout trade into all-time high territory. That trade will trigger once FTNT takes out $28 to $28.82 with high-volume.

Traders should now look for long-biased trades of those levels are taken out with volume that's near or well above 2 million shares. If we get that action soon, look for FTNT to tag $30 or higher in the near-term. I would avoid FTNT from the long side if the stock moves back below its 50-day with high-volume.

Optimer Pharmaceuticals

Optimer Pharmaceuticals

(OPTR)

is a biopharmaceutical company focused on discovering, developing and commercializing hospital specialty products. This stock is trading up 6% at $14.89 in recent trading.

Today's Volume: 808,000

Average Volume: 598,536

Volume % Change: 159%

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From a technical perspective, OPTR is soaring higher today on above average volume. This move has now pushed OPTR into breakout territory since its moving above some near-term overhead resistance at $14.71.

Traders should now look for long-biased trades in OPTR once it triggers its next big breakout over $14.95 to $15.40 with high volume. Look for a sustained move or close above those levels on volume that's near or well above 598,536 shares. If we get that action soon, then OPTR could easily hit its 2011 high of $17.95 pretty quickly.

AmSurg

AmSurg

(AMSG)

is engaged in developing, acquiring and operating ambulatory surgery centers in partnership with physicians throughout the U.S. The stock is trading up 9.4% at $29.50 in recent trading.

Today's Volume: 277,000

Average Volume: 137,208

Volume % Change: 271%

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Shares of AMSG are soaring today after the company reported a 35% jump in first-quarter earnings. AmSurg reported earnings of $15.7 million, or 50 cents per share, on revenue of $230 million.

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From a technical perspective, AMSG is skyrocketing today on heavy volume, and it's now triggered a near-term breakout trade with shares trending above resistance at $28.33. Traders should now look for continued upside momentum if AMSG can manage to close near its daily highs. At last check, AMSG has hit an intraday high of $29.78 and volume is well above daily action.

Traders should continue look for long-biased trades if we get that strong close, and as long as AMSG is trending above its breakout level of 28.33 with strong upside volume flows. Target a possibly run towards $35 in the near future.

ARM Holdings

ARM Holdings

(ARMH)

designs microprocessors, physical intellectual property and related technology and software, and sells development tools. This stock is trading up 2.1% at $25.70 in recent trading.

Today's Volume: 4.3 million

Average Volume: 2.9 million

Volume % Change: 242%

Shares of ARMH are ripping higher today after Raymond James upgraded the stock to strong buy from outperform, with a $35 price target, after the company reported first-quarter results that beat Wall Street estimates.

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From a technical perspective, ARMH is bouncing hard today near some previous support zones at around $25 with high-volume. This move follows a gap-down in price from yesterday from $27 to a low of $25.05.

Traders should now look for long-biased trades as long as AMRH is trending above the gap-down day high of $26.22 with strong volume. Look for more of that gap to get filled if AMRH can get above $26.22. I would avoid this stock from the long side if it's trending below that gap down day high, since it will put $25 into range of being broken to the downside.

Homeowners Choice

Homeowners Choice

( HCII) is a property and casualty insurance holding company. This stock is trading up 3.6% at $13.48 in recent trading.

Today's Volume: 94,000

Average Volume: 57,367

Volume % Change: 200%

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From a technical perspective, HCII is moving notably higher today on above average volume. This move is quickly pushing HCII within range of triggering a major breakout trade. That trade will hit once HCII takes out some near-term overhead resistance at $14.14 with high-volume.

Traders should now look for long-biased trades in HCII if it can sustain a move or close over $14.14 with volume that's near or well above 57,367 shares. If we get that action today or soon, look for HCII to continue its uptrend possibly towards $20 in the near future.

Onyx Pharmaceuticals

Onyx Pharmaceuticals

(ONXX)

is a biopharmaceutical company. Onyx Pharmaceuticals is developing therapies that target the molecular mechanisms that cause cancer. This stock is trading up 7.6% at $46.74 in recent trading.

Today's Volume: 3,652,000

Average Volume: 860,141

Volume % Change: 689%

From a technical perspective, ONXX is moving sharply higher today on monster volume. This move has now pushed ONXX into breakout territory with the stock trending above some past overhead resistance at $46.07.

Traders should now look for long-biased trades in ONXX as long as it closes near its daily highs, and if it continues to trend above $46.07. I would consider any upside volume day that's greater than 860,141 shares as bullish. Today's volume is well and beyond bullish, and its makes this breakout even more significant. Target a move back toward $50 to $60 if ONXX can hold this breakout.

As of the most recently reported period, Onyx was one of

D.E. Shaw's top holdings

.

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.