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.>>5 Dividend Stocks Itching to Pay You More 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 Breakout Stock Plays: Must-See Charts With that in mind, let's take a look at several stocks rising on unusual volume today. Ligand Pharmaceuticals ( LGND) This company focuses on drug discovery & early-stage development of pharmaceuticals that address critical unmet medical needs or that are more effective or safer than existing therapies, more convenient to administer & are cost effective. This stock is trading up 14% at $19.02 in recent trading. Today's Volume: 957,000 Average Volume: 85,914 Volume % Change: 1346% Shares of LGND are soaring today after the FDA approved PROMACTA for the treatment of low blood platelet counts in patients with chronic hepatitis C. From a technical perspective, LGND is exploding higher here back above its 50-day moving average of $17.17 with monster volume. This move has also pushed LGND into breakout territory, since the stock has taken out some near-term overhead resistance levels at $10 to $19. Shares of LGND are now moving within range of another major breakout trade. That trade will hit once LGND manages to take out some past overhead resistance at $19.85 with high volume. Traders should now look for long-biased trades in LGND as long as it's trending above $18, and then once it sustains a move or close above $19.85 with volume that hits near or above 85,914 shares. If that breakout triggers soon, then LGND will set up to trend north of $20. Keep in mind that any move above $19.85 will push LGND into new 52-week high territory, which is bullish technical price action.