2010 10-K: Part II 86 In 2010, operating expense in this segment rose $14.1 million, or  35.8%, after declining $11.9 million, or 23.2%, in 2009. Approximately  40% of the segment’s operating expense increase reflects recent  acquisitions. Higher salaries and incentive compensation, including  In 2010, operating income for the Investment Management segment  increased $3.9 million, or 7.4%, as revenue increased more than  operating expense. In contrast, 2009 operating income declined  $7.5 million, or 12.4%, as reductions in operating expense were not  sufficient enough to outweigh the revenue decline. Morningstar Managed Portfolios also contributed to the segment’s  revenue increase in 2010, although to a lesser extent than Retirement  Advice. The higher revenue mainly reflects higher average asset  levels during 2010 compared with 2009. Assets under management  for Morningstar Managed Portfolios were $2.7 billion as of December  31, 2010 compared with $2.1 billion as of December 31, 2009 and  $1.6 billion as of December 31, 2008, reflecting positive equity mar- ket returns and net inflows. Assets under management for Retirement Advice increased to $19.6  billion as of December 31, 2010, compared with $15.7 billion as of  December 31, 2009 and $11.0 billion as of December 31, 2008. We cannot separately quantify the factors affecting assets under  management for our managed retirement accounts. These factors  primarily consist of employer and employee contributions, plan  administrative fees, market movements, and participant loans and  hardship withdrawals. We cannot quantify the impact of these other  factors because the information we receive from the plan providers  does not separately identify these transactions or the changes in  balances due to market movement. The tables below show the breakdown of retirement plan participants  who had access to the services offered through Morningstar  Retirement Manager and Advice by Ibbotson, as well as the number  of plan sponsors and plan providers that provide this access. Total assets under advisement for Investment Consulting as of  December 31, 2009 declined approximately 7.3% compared with  December 31, 2008, as assets under advisement from Morningstar  Associates declined 27.4%, which was partially offset by assets  under advisement from Ibbotson Associates, which increased about  9.0%. The majority of the asset decline in 2009 reflects the loss of  one of the contracts discussed above, partially offset by positive  market performance, and, to a lesser extent, from net inflows and  new client wins in assets under advisement. We cannot separately quantify cash inflows and outflows for these  portfolios because we do not have custody of the assets in the  majority of our investment management business. The information  we receive from our clients does not separately identify the impact  of cash inflows and outflows on asset balances for each period. We  also cannot precisely quantify the impact of market appreciation or  depreciation because the majority of our clients have discretionary  authority to implement their own portfolio allocations. Morningstar Managed Portfolios Assets under Management for Managed Retirement Accounts Operating Income Assets under management for managed As of December 31 retirement accounts ($ billions) 2010  2009   2008 Advice by Ibbotson $ 17.6 $ 14.2  $ 10.0 Morningstar Retirement Manager  2.0 1.5  1.0 Total  $ 19.6 $ 15.7  $ 11.0 As of December 31 Plan Participants (millions)  2010 2009  2008 Advice by Ibbotson 10.1 9.5  8.9 Morningstar Retirement Manager  13.4 11.2  8.3 Total  23.5 20.7  17.2 Plan Sponsors (approximate)  2010 2009  2008 Advice by Ibbotson 68,000 68,000  68,000 Morningstar Retirement Manager  82,000 83,000  72,000 Total  150,000 151,000   140,000 Plan Providers  2010 2009  2008 Advice by Ibbotson 7 7  7 Morningstar Retirement Manager  16 16  17 Total  23 23  24