"The working group's objective was to address the concern that some defined contribution plans may be invested in an undue concentration of plan sponsor assets.... The Work Group unanimously recommends that [with respect to publically traded securities], at a minimum, the ESOP diversification rules be extended to all participants in defined contribution plans (except ESOPs).... The Work Group unanimously recommends a limit on the investment of defined contribution assets in non-publically traded employer securities equal to ten percent of the market value of plan assets or that the plan follow the ESOP rules with respect to employer securities." [Prepared for the Pension and Welfare Benefits Administration by members of the Advisory Council on Employee Welfare and Pension Benefits Plans.]