The following table shows the realized gains and losses recorded  in our Consolidated Statements of Income arising from sales of our  investments classified as available-for-sale: As of December 31, 2010 and 2009, investments with unrealized  losses for greater than a 12-month period were not material to the  Consolidated Balance Sheets and were not deemed to have other  than temporary declines in value. The table below shows the cost and fair value of investments clas- sified as available-for-sale and held-to-maturity based on their  contractual maturities as of December 31, 2010 and 2009. The  expected maturities of certain fixed-income securities may differ  from their contractual maturities because some of these holdings  have call features that allow the issuers the right to prepay obliga- tions without penalties. The following table shows the net unrealized gains (losses) on trad- ing securities as recorded in our Consolidated Statements of Income: The fair value of our assets subject to fair value measurements and  the necessary disclosures are as follows: Held-to-maturity investments include a $1,600,000 certificate of  deposit held as collateral against two bank guarantees for our office  lease in Australia. Level 1: Valuations based on quoted prices in active markets for identical assets or liabil- ities that we have the ability to access. Level 2: Valuations based on quoted prices in markets that are not active or for which all  significant inputs are observable, either directly or indirectly. Level 3: Valuations based on inputs that are unobservable and significant to the overall  fair value measurement. Morningstar, Inc. 2010 Annual Report 115 ($000)  2010 2009  2008 Realized gains  $ 276 $ —  $  1 Realized losses  (1) —   (5) Realized gains (loss), net  $ 275 $ —  $ (4) ($000)  2010 2009  2008 Unrealized gains (losses), net  $ 237 $ 1,233  $ (971) Fair Value Measurements  Using Fair Value Hierarchy ($000)   Fair Value  Level 1  Level 2  Level 3 December 31, 2010 Available-for-sale investments  Government obligations  $ 113,577  $ 113,577  $ —  $ — Corporate bonds 42,878  42,878  —   — Commercial paper  2,991  2,991 Equity securities 4,922  4,922  —   — Mutual funds  8,704  8,704  —   — Trading securities  4,692  4,692  —   — Total  $ 177,764  $ 177,764  $ —  $ — December 31, 2009 Available-for-sale investments  Government obligations  $ 174,822  $ 174,822  $ —  $ — Corporate bonds 12,311  12,311  —   — Equity securities 2,173  2,173  —   — Commercial paper  —  —  —   — Mutual funds  8,000  8,000  —   — Trading securities  4,163  4,163  —   — Total  $ 201,469  $ 201,469  $ —  $ — ($000)  Cost   Fair Value As of December 31, 2010 Available-for-sale: Due in one year or less  $ 85,990  $ 85,964 Due in one to three years 73,440  73,482 Equity securities and mutual funds  12,656  13,626 Total  $ 172,086  $ 173,072 Held-to-maturity:  Due in one year or less  $  7,223  $  7,223 Due in one to three years 253  253 Total  $  7,476  $  7,476 As of December 31, 2009 Available-for-sale: Due in one year or less  $ 161,453  $ 161,817 Due in one to three years 25,248  25,316 Equity securities and mutual funds  10,013  10,173 Total  $ 196,714  $ 197,306 Held-to-maturity:  Due in one year or less  $ 10,587  $ 10,587 Due in one to three years 1  1 Total  $ 10,588  $ 10,588