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 .
In the context of the input sentence, determine the relationship between 'Citigroup' and 'BlackRock'.
Options: developer, parent organization, headquarters location, owned by