The ones simply with the ability to put a stop to the squabbling is the "government". They would basically have a monopoly on the use of force. You would not have anything less than this, due to nature of human/animal hierarchical social structures.
You do understand that the concept of a monopoly on force is only as old as Machiavelli?
Market law and rights protection would do a hell of a lot better job than a monopoly.
Tell me, how exactly would a huge bank harm the public?
The same way it does now
By influencing the government? What government?