Some banks in luxembourg that do exactly that. Obviously with VIP clients. They use omnibus accounts at the end of the year. The balance of the account remains as the client requests. At the beginning of the year the account is left with the full balance.So imagine you have $1,000,000,000 pass through your account and leave balance always at zero. You thiink there will be no reporting of that account?
Without leaving the European Union, without tax havens, without offshore accounts,... only paying big commissions and being a VIP clients.
And it is legal.