Have a read of this: http://en.wikipedia.org/wiki/Criticisms_of_corporations Share prices may drop and therefore adversely affect shareholders, but they have no control over the corporation generally in its day to day operations...managers can mismanage for their own short term gains hoping not to get caught, by the time they get caught it is too late, they have already benefitted and shareholders still holding the stock lose out. Shareholders (in joint stock companies) should be able to control the company like anyone else...I am not sure if this is shariah compliant either.
Why are you against stock markets? I was going to start to go into them