These are VERY long reads, but they will provide you with some information that you, perhaps, did not know. Primary is that BLM is a decentralized organization; it does not have “member branches.”
https://en.wikipedia.org/wiki/Black_Lives_Matter
I’m “lazy,” so I’m depending on Wikipedia to provide this basic information. You can look for yourself to see in how many places BLM is active and how it gets funded. I’ve pointed out to another responder that Patrisse Cullors has a development contract with Warner Brothers, which provided a goodly sum of money to her. Both Cullors and Garza are published authors and get income from their books. BLM is subject to all sorts of disparagement and scrutiny. If any number of anti-BLM groups had the opportunity to prove fiscal irregularities, then you know they would have done so by now. Perhaps what some respondents consider “old news” is not news at all.