Alex Mashinsky's wallet addresses based on his transaction history file dating back to 2018. I received this file from a Celsius Network employee.
A number of these are known exchange withdrawal wallets
0x503828976d22510aad0201ac7ec88293211d23da - Coinbase
0x59a5208b32e627891c389ebafc644145224006e8 - HitBTC
0x75db8b92937f8f86213e523788ab9f066efde3fe - Celsius
0x91e9a131446ab538d30746c79d43908faef3f289 - Celsius withdrawals and CEL distributions for insiders
Source: Arkham Intelligence