What is the relationship between Citigroup and BlackRock 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.

The full line-up consists of Bank of America Merrill Lynch , BNY Mellon , BlackRock , Citadel, Citigroup , Credit Suisse , Deutsche Bank , Goldman Sachs , HSBC, Jefferies , JPMorgan , Maverick Capital, Morgan Stanley , Nomura and Wells Fargo .

Answer: owned_by