Stock Quotes in this Article: ARMH, BOFI, SNTS, SOHU, ACRX

DELAFIELD, 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.

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

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.

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

Santarus

Santarus (SNTS) is a specialty biopharmaceutical company focused on acquiring, developing and commercializing proprietary products that address the needs of patients treated by physician specialists. This stock is trading up 7% at $23.57 in recent trading.

Today's Volume: 2.41 million

Average Volume: 1.28 million

Volume % Change: 240%

Shares of SNTS are ripping higher today after JMP Securities initiated the stock with an outperform rating and $27 per share price target.

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From a technical perspective, SNTS is soaring higher here right above its 50-day moving average of $21.10 with strong upside volume. This move has pushed shares of SNTS into breakout territory, since the stock has taken out some near-term overhead resistance at $22.40. Shares of SNTS are now quickly moving within range of triggering another major breakout trade, which will hit if SNTS manages to take out its 52-week high at $24 with high volume.

Traders should now look for long-biased trades in SNTS as long as it's trending above that first breakout level of $22.40, and then once it sustains a move or close above its 52-week high at $24 with volume that hits near or above 1.28 shares. If that breakout triggers soon, then SNTS will set up to enter new 52-week-high territory, which is bullish technical price action. Some possible upside targets off that breakout are $28 to $30.

Sohu.com

Sohu.com (SOHU) is a Chinese online media, search, gaming, community and mobile service group. This stock is trading up % at $78.50 in recent trading.

Today's Volume: 1.16 million

Average Volume: 792,506

Volume % Change: 128%

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From a technical perspective, SOHU is trending higher here right above its 50-day moving average of $61.43 with above-average volume. This move is quickly pushing shares of SOHU within range of triggering a major breakout trade. That trade will hit if SOHU manages to take out some near-term overhead resistance levels at $67.76 to its 52-week high at $68.58 with high volume.

Traders should now look for long-biased trades in SOHU as long as it's trending above today's low of $64 and then once it sustains a move or close above those breakout levels with volume that hits near or above 792,506 shares. If that breakout triggers soon, then SOHU will set up to enter new 52-week-high territory, which is bullish technical price action. Some possible upside targets off that breakout are $70 to $75 or even $80.

Bofi

Bofi (BOFI) is a bank holding company for Bank of Internet USA, a consumer-focused, nationwide savings bank operating mainly over the Internet. This stock is trading up 1.7% at $48.44 in recent trading.

Today's Volume: 164,000

Average Volume: 159,802

Volume % Change: 51%

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From a technical perspective, BOFI is trending modestly higher here right above some near-term support at $46 with decent upside volume. This stock has been uptrending very strong for the last six months, with shares soaring higher from its low of $29.75 to its recent high of $49.98. During that uptrend, shares of BOFI have been consistently making higher lows and higher highs, which is bullish technical price action. That move has now pushed shares of BOFI within range of triggering a major breakout trade. That trade will hit if BOFI manages to clear its 52-week high at $49.98 with high volume.

Traders should now look for long-biased trades in BOFI as long as it's trending above some near-term support at $46, and then once it sustains a move or close above its 52-week high at $49.98 with volume that this near or above 159,802 shares. If that breakout triggers soon, then BOFI will set up to enter new 52-week-high territory, which is bullish technical price action. Some possible upside targets off that breakout are $55 to $60.

ARM Holdings

ARM Holdings (ARMH) designs microprocessors, physical IP and related technology and software, and sells development tools to enhance the performance, cost-effectiveness and energy-efficiency of high-volume embedded applications. This stock is trading up 1% at $38.47 in recent trading.

Today's Volume: 3.10 million

Average Volume: 2.52 million

Volume % Change: 91%

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From a technical perspective, ARMH is trending modestly higher here with above-average volume. This stock has been uptrending with big upside volume flows for the last few weeks, with shares moving higher from its low of $34.75 to its intraday high of $38.68. During that move, shares of ARMH have been consistently making higher lows and higher highs, which is bullish technical price action. That move has now pushed shares of ARMH within range of triggering a near-term breakout trade. That trade will hit if ARMH manages to take out its 200-day at $38.89 with high volume.

Traders should now look for long-biased trades in ARMH as long as it's trending above some key near-term support at $37 and then once it sustains a move or close above its 200-day at $38.89 with volume that's near or above 2.52 million shares. If that breakout triggers soon, then ARMH will set up to re-test or possibly take out its next major overhead resistance levels at $41 to its 50-day at $43.08. Any high-volume move above those levels will then put $45 to $46 into range for shares of ARMH.

AcelRx Pharmaceuticals

AcelRx Pharmaceuticals (ACRX) is a clinical-stage biopharmaceutical company engaged in discovery and development of novel small molecule therapeutics that modulate muscle function for the potential treatment of serious diseases and medical conditions. This stock is trading up 3.6% at $10.67 in recent trading.

Today's Volume: 572,000

Average Volume: 509,787

Volume % Change: 61%

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From a technical perspective, ACRX is trending higher here right above some near-term support at $10 with above-average volume. This stock has been uptrending very strong for the last four months, with shares soaring higher from its low of $4.31 to its recent high of $11.77. During that uptrend, shares of ACRX have been consistently making higher lows and higher highs, which is bullish technical price action. That move has now pushed shares of ACRX within range of triggering a major breakout trade. That trade will hit if ACRX manages to take out its all-time high at $11.77 with high volume.

Traders should now look for long-biased trades in ACRX as long as it's trending above some key near-term support at $10 and then once it sustains a move or close above its all-time high at $11.77 with volume that's near or above 509,787 shares. If that breakout triggers soon, then ACRX will set up to enter new all-time-high territory, which is bullish technical price action. Some possible upside targets off that breakout are $15 to $17.

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

-- Written by Roberto Pedone in Delafield, Wis.

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

Roberto Pedone, based out of Delafield, 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.