They are indeed not a government regulator but, in practice, Federal law does require membership in FINRA for broker-dealers. See for instance: https://www.la

They are indeed not a government regulator but, in practice, Federal law does require membership in FINRA for broker-dealers. See for instance: https://www.law.cornell.edu/cfr/text/17/240.15b7-1 https://www.law.cornell.edu/cfr/text/17/240.15b7-1 FINRA is the only national securities association.