Sirius XM Radio is having an interesting year. The satellite radio operator’s share price is down 88% in the last 12 months, but up 204% in 2009. Why the volatile ebb and flow?

You see it all the time; a stock jumps 20-30% in just a few days. Suddenly, the average investor sees what is happening and decides to join the bandwagon, hoping to catch some of the move. After jumping in, the stock comes down 15% and the investor is at a loss.