New York–based BlackRock is the world’s largest asset manager, with $4.65 trillion in assets under management, yet its fund-of-funds business, established in 2003, has stayed largely under the radar. In October 2007 the firm acquired the fund-of-funds business of Quellos Group, No. 14 on Alpha’s Fund of Funds 50 ranking in 2007, for $1.7 billion. By buying a firm with a track record, BlackRock was able to expand its $5.4 billion fund-of-hedge-funds business overnight…