BlackRock (BLK) reported fourth-quarter net income of $555 million, or $3.05 a share, dropping 16% from a year earlier when the investment behemoth earned $657 million, or $3.35 a share. BlackRock earned $2.23 billion, or $11.85 a share, for the year, an 8% increase over $2.13 billion, or $10.94 a share, for 2010. The company beat analysts' fourth quarter earnings estimates of $3 a share, despite shaky economic conditions in multiple markets for the global investor, but missed full year 2011 estimates of $11.90 a share. Revenue for the three months ended Dec. 31 fell 11% to $2.34 billion from $2.06 billion a year ago, while full year revenue rose 10% from $8.16 billion in 2010 to $9.08 billion in 2011. Operating income in the period, excluding costs from exiting two U.K. leases and other items, fell 14% to $808 million from $940 million for the fourth quarter of 2010. BlackRock's assets under management closed the quarter at $3.51 trillion, up 5% since third quarter-end and down 1% since year-end 2010, reflecting strong inflows of $23.8 billion in long-term products — equity, fixed income, multi-asset class and alternative investments — and a $143.3 billion improvement in market and investment performance. “As we enter 2012, improved economic indicators have served to provide greater market stability and the environment feels more constructive overall, but it is likely that political and regulatory dynamics, persistent low rates, continued divergence between developing and developed economies and protracted periods of heightened volatility will remain key factors," said BlackRock CEO Laurence Fink. Write to Justin T. Hilley. Follow him on Twitter @JustinHilley.