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 "Magic Formula" Stocks for 2013 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. >>Outwit the S&P in 2013 With 5 Hated Stocks With that in mind, let's take a look at several stocks rising on unusual volume today. CAI International ( CAP) This is an intermodal freight container leasing and management company, which operates its business through two segments: container leasing and container management. This stock is trading up 5.2% at $21.19 in recent trading. Today's Volume: 847,000 Average Volume: 148,040 Volume % Change: 1195% From a technical perspective, CAP is ripping higher here right off its 200-day moving average of $20.04 with heavy upside volume. This move is quickly pushing CAP within range of triggering a near-term breakout trade. That trade will hit once CAP takes out some near-term overhead resistance at its 50-day of $21.26 and then more overhead resistance at $22 with high volume. Traders should now look for long-biased trades in CAP as long as it's trending above its 200-day at $20.04, and then once it sustains a move or close above those breakout levels with volume that hits near or above 148,040 shares. If that breakout triggers soon, then CAP will set up to re-test or possibly take out its next major overhead resistance levels at $23 to $23.55. Apogee Enterprises ( APOG) This company provides technologies, involving the design and development of value-added glass products, services and systems. This stock is trading up 3.2% at $24.49 in recent trading.