What is the relationship between Citigroup and Financial Services 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.

By Bloomberg News × Photo: Buck Ennis Citigroup sold $4.2 billion of private loans and $3.4 billion of securitized loans to Discover Financial Services in 2010.

Answer: industry