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.>>5 Stocks Poised for Breakouts 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 Big Stocks to Trade for Big Gains With that in mind, let's take a look at several stocks rising on unusual volume today. Iron Mountain Iron Mountain ( IRM) is a global provider of information protection and storage services. This stock closed up 5.8% to $30.15 in Friday's trading session. Friday's Volume: 7.28 million
Three-Month Average Volume: 1.71 million
Volume % Change: 392% >>5 Stocks With Big Insider Buying From a technical perspective, IRM spiked sharply higher here and broke out above some key overhead resistance at $29.06 with heavy upside volume. This move also pushed shares of IRM into its previous gap down zone from June that started near $34. Market players should now look for a continuation move higher in the short-term if IRM can manage to take out Friday's high of $30.31 and its 200-day moving average at $30.69 with high volume. Traders should now look for long-biased trades in IRM as long as it's trending above Friday's low of $28.45 and then once it sustains a move or close above $30.31 to $30.69 with volume that hits near or above 1.71 million shares. If we get that move soon, then IRM will set up to re-test or possibly take out its next major overhead resistance levels at $34 to $36. Healthcare Services Group Healthcare Services Group ( HCSG) provides management, administrative and operating expertise and services to the housekeeping, laundry, linen, facility maintenance and dietary service departments of the health care industry in the U.S. This stock closed up 3.9% to $28 in Friday's trading session.