What is the relationship between Banamex and Citigroup in the context of the input sentence. Choose an answer from: product/material produced; manufacturer; distributed by; industry; position held; original broadcaster; owned by; founded by; distribution format; headquarters location; stock exchange; currency; parent organization; chief executive officer; director/manager; owner of; operator; member of; employer; chairperson; platform; subsidiary; legal form; publisher; developer; brand; business division; location of formation; creator.

Citigroup Inc. on Wednesday confirmed that it will close Banamex USA, a small unit doing business across the U.S.-Mexico border, and agreed to pay $140 million to regulators who said the unit hadn’t done enough to protect itself from money launderers.
operator