https://www.thetradenews.com/majority-of-prop-trading-firms-obliged-to-join-finra-under-expanded-sec-rule/
(If I read this right) This post only relates to SEC broker Dealers that were member exchanges but regulated by exchanges not FINRA. This does not refer to Prop firms that are not Broker Dealers.
%% HAVE not read all the details; a lawsuit against the SEC could change anything. This SEC seems > better than average, they reduced SEC fees some.
weren't broker dealers always required to join finra? I worked for an 8 person BD years ago and everyone had to do the full background; we had no clients or outside $
All Broker Dealers are required to register with the SEC and then a self-regulatory organization (SRO). I was an AMEX member that did their own regulation until the contracted with FINRA to do it. I think they might have reverted back to their own regulation a few years ago, because they were hiring.