From the US perspective, the markets run at a healthy profit; they surely generate far more in taxes than they require in regulatory expenditures. And the excha

From the US perspective, the markets run at a healthy profit; they surely generate far more in taxes than they require in regulatory expenditures. And the exchanges themselves do much of the policing of companies, so the actual costs are low. Public markets require the same sort of policing as public streets if they're to remain reasonably safe and effective for the public.