This article begins: "The big Wall Street banks are making tens of billions of dollars a year in the derivatives market." As I understand it the writer goes on to say that a derivative is a "side bet." Combining these two statements it then appears that the banks are making these side bets and winning many more of them than they are losing - thereby making their tens of billions. If the banks are winning all of that money the next obvious question is, "who are the losers?" I don't understand who, or what entity, would continue to make side bets with the banks when it has become obvious that the banks are winning billions as a result. Can anyone shed some light on this?