All markets are sum equal to zero, yes, where supply equals demand the sum is basically zero.
The point is that markets are dynamic and when something happens that make some actors to think the price has to change, i.e. 11/09, Greek crisis and /or some fundamental indicators announcement the markets start moving untill the price equilibrates again supply and demand, basically markets are equilibrated by price (i know some will say i am wrong), so until the markets find its equilibrium again, the chance to make money will be there for those who have enough information as to anticipate those movements.
The point is that markets are dynamic and when something happens that make some actors to think the price has to change, i.e. 11/09, Greek crisis and /or some fundamental indicators announcement the markets start moving untill the price equilibrates again supply and demand, basically markets are equilibrated by price (i know some will say i am wrong), so until the markets find its equilibrium again, the chance to make money will be there for those who have enough information as to anticipate those movements.
