How can any trade be made and not know 'who' made the trade? Doesn't every trading account need to be registered/identified in some manner? KYC right? At a m

How can any trade be made and not know 'who' made the trade? Doesn't every trading account need to be registered/identified in some manner? KYC right? At a minimum the account holder would want to transfer funds to/from account.... I can't even buy sudafed without 3 forms of ID, yet we have 'invisible' traders of millions of dollars?