Coinspeaker Citigroup Joins the Big 6 with Its Robo-Advisor, It Will Be Free for Some CustomersCitigroup is one of the biggest six U.S. banks that decided to have a robo-advisor. In the case of Citigroup, it will be free for customers with at least $50,000 in investments or deposits at the bank.Citigroup Joins the Big 6 with Its Robo-Advisor, It Will Be Free for Some Customers