Binance, Poloniex and Huobi have powered their customers' funds and proxied the voting power to an account owned by Justin Sun, as can be seen here: https://steemd.com/@dev365
But the total amount of STEEM held on those three exchanges is about 44M as can be seen from this report: https://steempeak.com/hive-133987/@penguinpablo/weekly-report-how-much-steem-is-stored-on-the-exchanges-february-27-2020
Somehow the math doesn't add up. It doesn't get the 
RE: Your stake in Steem on centralized exchanges was just used to take over the Steem Blockchain