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.

Symphony was formed when, in October of last year, fourteen of the world’s biggest financial-services firms, including Goldman Sachs, bought instant-messaging software company Perzo Inc and formed a new company funded by a consortium of financial firms that includes many big names —Goldman Sachs GS, +0.64% , Bank of America Corp BAC, +0.45% ., Bank of New York Mellon Corp BK, +0.46% ., BlackRock Inc. BLK, +0.68% , Citadel LLC, Citigroup Inc. C, +0.45% , Credit Suisse Group AG CS, -0.14% , Deutsche Bank AG DB, -1.01% , J.P. Morgan Chase & Co. JPM, +0.50% , Jefferies LLC, Maverick Capital Ltd., Morgan Stanley MS, +0.79% , Nomura Holdings Inc. NMR, +0.44% and Wells Fargo & Co. WFC, +0.77% .

Answer: owned_by