So when you say paper bitcoin, do you mean entities like Blackrock and ETF issuers selling shares that may not be backed by bitcoin? Essentially "satisfying" demand without any actual supply being taken up??
Discussion
Most likely Binance, but would not be shocked in the least to discover negligence across US based CEXs. They know a majority are not going to want to hold in cold storage, so no real fear of a run of withdrawals to cold storage.