Utilize the input text as a context reference, choose the right relationship between Citigroup and BlackRock from the options. Options: 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