But people outside the firm do know who they are.For starters, Strategy has repeatedly cited its “various custody arrangements”—there is no one exclusive custodian that’s holding onto its nearly $72 billion worth of BTC on the company’s behalf. A spokesperson for Coinbase confirmed it is one of Strategy's custodians when asked by Decrypt—but stressed that MSTR has previously named Coinbase as one of its custodians.
https://decrypt.co/330556/coinbase-custody-strategy-bitcoin-who-doesSince Strategy uses custodians regulated and licensed by NYDFS and these companies are very limited all over the world, I think that if they implement different rules in the future under the pretext of security, it will interfere with the freedom of Bitcoin. Because so far NYDFS (New York Department of Financial Services) has given this license to only 9 companies, among them are the names of BitGo, NYDIG, Gemini, Fidelity and Coinbase.