It is suspected that the CEX cold wallet address has been increasing its holdings by 1000 BTC daily since the end of August, currently holding 12,500 BTC

According to HODL15Capital's monitoring, a certain address ("Mr.500") increased its holdings by 500 BTC on August 26th, and subsequently added 500 BTC each day through two transactions (a total of 1000 BTC). As of September 7th, this address holds 12,500 BTC, approximately equivalent to $677 million USD. HODL15Capital added that this seems to be a cold wallet address of CEX but it has not been confirmed.