The payment is the second to result from the state’s investigation of Citigroup’s Global Markets Inc. subsidiary.

An investment subsidiary of Citigroup has agreed to return approximately $657,000 to customers who were overcharged fees on their investment accounts – including at least four dozen customers in Western New York.

TIMOTHY A. CLARY/AFP/Getty Images Citigroup Global Markets will refund more than $4.5 million to 31,000 customers who were wrongly billed for management fees for accounts that were inactive, including more than 1,000 people in New York City.

Customers did not receive fee rebates they were entitled to when their accounts were frozen, according to the attorney general’s office.

New York Attorney General Eric T. Schneiderman’s office said CGMI assessed fees to customer accounts that were inactive for certain time periods even though no charges should have hit those dormant accounts. So far, the investigation has led to repayments (or planned repayments) of more than $20.5 million to more than 46,000 customers.

“I want to thank Citi for its continued cooperation with our investigation, which has ensured that Citi customers are getting back the money they deserve”, Schneiderman said in a statement.

Schneiderman’s office began an investigation into CGMI in 2012 after a Westchester resident reported fee overcharge issues.

Citigroup’s review revealed that if a customer requested a refund of fees paid covering a frozen period, Global Markets sometimes rebated the fees, but in thousands of cases it did not.

Hamlin resident Amy Schultz was arrested after a joint investigation by the Attorney General’s Medicaid Fraud Unit and the Department of Health’s Bureau of Narcotics Enforcement.