Citigroup Global Markets Inc (CGMI), a unit of Citigroup Inc, has agreed with the New York attorney general to return $4.5 million in account management fees charged on some 15,000 frozen accounts. As a result of the agreement, a total of more than $20 million will be refunded to Citi customers for overcharges in an investigation initiated by New York Attorney General Eric Schneiderman. In October, CGMI agreed return some $16 million to more than 31,000 customers who paid higher advisory fees than they had negotiated.