1. There is no law or rule of what is the minimum proportion that the top couple percent will own, other than that it cannot be less than their couple percent.
2. There is no absolutely direct relation between the wealth distribution and the ownership and control of the capital stock, although obviously there tends to be. There are wealth distributions in socialist countries where the state owns the means of production. Some people own more stuff than others. There were always people in the former Soviet Union whose families owned all kinds of valuable stuff. None of it was stocks that gave ownership and control of the capital stock, however, although many of these people were in the nomenklatura and thus had more control (if not ownership) than those not in the nomenklatura.
3. Actually even an even distribution can be described mathematically as an extreme case of the Pareto distribution. Barkley Rosser