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.Major moves in volume can signal unusual activity, such as insider buying or selling -- or buying or selling by "superinvestors." >>5 Stocks Set to Soar on Bullish Earnings 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. >>5 Stocks Poised for Breakouts Republic Airway Republic Airway ( RJET) offers scheduled passenger services through its wholly owned operating air carrier subsidiaries: Chautauqua Airlines, Shuttle America Corporation, Republic Airline and Frontier Airlines. This stock is trading up 5% at $10.46 in recent trading. Today's Volume: 1.19 million Average Volume: 580,110 Volume % Change: 178% From a technical perspective, RJET is ripping higher here right above some near-term support at $9 with heavy upside volume. This move has started to push shares of RJET into breakout territory and new 52-week-high territory, since the stock has cleared some near-term overhead resistance at $9.94. Traders should now look for long-biased trades in RJET as long as it's trending above $9.94 and then once it sustains a move or close above its new 52-week high of $10.50 with volume that hits near or above 580,110 shares. If that RJET can maintain that trend, then this stock could possibly hit $12 to $13 in the near future. Stratasys Stratasys ( SSYS) is a manufacturer of three-dimensional printers and high-performance rapid prototyping systems for the office-based RP and direct digital manufacturing markets. This stock is trading up 6.9% at $68.17 in recent trading.