This excerpt taken from the UNH 10-Q filed May 7, 2009.
Investment and Other Income. The decrease in investment and other income in 2009 was primarily due to capital market conditions causing lower investment yields and a decrease in realized gains.
Medical costs for three months ended March 31, 2009 increased primarily due to the factors that increased premium revenues described above.
Our consolidated medical care ratio was flat year-over-year with improvements in the medical care ratio for the commercial risk-based business offset by the mix effect from growth in our public and senior markets businesses, which have higher medical care ratios.
For each period, our operating results include the effects of revisions in medical cost estimates related to all prior periods. Changes in medical cost estimates related to prior periods, resulting from more complete claim information identified in the current period, are included in total medical costs reported for the current period. Medical costs for both the three months ended March 31, 2009 and 2008 included $200 million of net favorable medical cost development related to prior fiscal years.