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. Often when above-average volume moves into an equity, it precedes a large spike in volatility.>>Outwit the S&P in 2013 With 5 Hated Stocks 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. >>5 "Magic Formula" Stocks for 2013 With that in mind, let's take a look at several stocks rising on unusual volume today. Auxilium Pharmaceuticals ( AUXL) This is a specialty biopharmaceutical company, which develops and markets products to urologists, endocrinologists, orthopedists and select primary care physicians and plastic surgeons who focus on the hand, and rheumatologists. This stock is trading up 4.4% at $18.35 in recent trading. Today's Volume: 666,000 Average Volume: 485,300 Volume % Change: 85% From a technical perspective, AUXL is ripping higher here right off some near-term support at $17.65 with above-average volume. This move is quickly pushing AUXL within range of triggering a near-term breakout trade. That trade will hit once AUXL manages to clear some near-term overhead resistance levels at $18.86 to $19.46 and then once it takes out its 50-day moving average at $19.83 with high volume. Traders should now look for long-biased trades in AUXL as long as it's trending above $17.65, and then once it sustains a move or close above those breakout levels with volume that hits near or above 485,300. If that breakout triggers soon, then AUXL will set up to re-test or possibly take out its 200-day moving average at $21.47. SodaStream International ( SODA) This company is engaged in developing, manufacturing and marketing home beverage carbonation systems and related products. This stock is trading up 6.6% at $43.27 in recent trading.