2010 10-K: Part II Pro Forma Information for 2010 and 2009 Acquisitions Intangible Assets We did not record any goodwill impairment losses in 2010, 2009, or  2008, respectively, as the estimated fair values exceeded the car- rying values of the reporting units. The following table summarizes our intangible assets: The following unaudited pro forma information presents a summary  of our Consolidated Statements of Income for the years ended  December 31, 2010 and 2009 as if we had completed the 2010 and  2009 acquisitions and had consolidated Morningstar Korea and  Morningstar Denmark as of January 1 of each of these years. In  calculating the pro forma information below, we included an estimate  of amortization expense related to the intangible assets acquired. Unaudited Pro Forma Financial Information ($000) 2010 2009 Revenue  $ 567,844 $ 535,568 Operating income $ 121,461 $ 125,451 Net income  $ 86,545 $ 82,536 Basic net income per share attributable $  1.75 $  1.72 to Morningstar, Inc.  Diluted net income per share attributable $  1.71 $  1.66 to Morningstar, Inc.  Goodwill The following table shows the changes in our goodwill balances  from January 1, 2009 to December 31, 2010: ($000) Balance as of January 1, 2009 $187,242 Adjustments to 2008 acquisitions: Acquisition of Tenfore Systems Limited 5,921 Acquisition of 10-K Wizard Technology, LLC 1,121 Acquisition of Fundamental Data Limited  (826) Acquisition of FCSI and InvestData Limited 285 2009 acquisitions: Acquisition of the equity research and data business of CPMS  5,727 Acquisition of Logical Information Machines, Inc.  34,298 Goodwill for four other acquisitions completed in 2009  3,225 Goodwill for Morningstar Korea 1,027 2010 acquisitions: Acquisition of Aegis Equities Research  5,534 Acquisition of Old Broad Street Research, Ltd.  12,422 Acquisition of Realpoint, LLC  23,103 Acquisition of remaining ownership in Morningstar Denmark  12,342 Acquisition of annuity intelligence business of Advanced Sales and Marketing Corp.  8,921 Acquisition of Footnoted business of Financial Fineprint Inc. and Seeds Group  3,972 Other, primarily currency translation  13,347 Balance as of December 31, 2010 $ 317,661 Weighted  Average   Accumulated Useful Life  ($000)  Gross   Amortization Net  (years) As of December 31, 2010 Intellectual property  $ 33,990  $ (15,970)  $ 18,020  10 Customer-related assets   130,675   (39,951)  90,724  11 Supplier relationships  240  (72)  168  20 Technology-based assets  78,651   (25,682)  52,969  9 Non-competition agreement  1,751  (909)  842  4 Intangible assets related 6,407  (107)  6,300  10 to acquisitions with preliminary purchase price allocations  Total intangible assets  $ 251,714  $ (82,691)  $ 169,023  10 As of December 31, 2009 Intellectual property  $ 28,472  $ (12,147)  $ 16,325  10 Customer-related assets  87,635   (27,405)  60,230  10 Supplier relationships  240  (60)  180  20 Technology-based assets  49,276   (16,694)  32,582  9 Non-competition agreement  820  (547)  273  5 Intangible assets related 26,129  (231)  25,898  5  to acquisitions with preliminary purchase price allocations Total intangible assets  $192,572  $ (57,084)  $ 135,488  9 The following table summarizes our amortization expense related  to intangible assets: ($000)  2010 2009  2008 Amortization expense  $ 24,850 $ 18,963  $ 16,648 126