For years, self-regulatory agencies (like FINRA or the Exchanges) have wielded the statutory authority granted them by Congress - and backed by the SEC - exercising governmental power to compel testimony, impose fines and punishments, and even bar a person or firm from an entire industry.
At the same time, they declaim that they're just membership organizations, so don't owe anyone Constitutional protections (like Fifth Amendment Due Process) and aren't subject to Equal Access to Justice Act claims for your litigation expenses when they lose.
So SROs essentially are the ...