A mysterious Bitcoin (CRYPTO: BTC) wallet address has been accumulating BTC in significant quantities since the start of November. Turns out, it’s a cold wallet owned by BitMEX. What Happened: The curtain has been raised on an address that went from zero to holding more than 10,000 BTC. Crypto exchange, BitMEX owns the wallet that, as of Nov. 30, has occupied the position of the 74th largest holder of Bitcoin. Speculations were doing rounds that it could be a new entity that is buying BTC amid the optimism surrounding spot bitcoin ETF filings in the U.S. Yesterday, it was reported that the wal…