MMC Benefits Handbook
Impact on Benefits
You should review your beneficiary designations. Generally, for life and accident insurance plans, you can name anyone you wish as a beneficiary, including a trust or an estate, or you can name more than one beneficiary who will split the benefit.
However, for the 401(k) Savings & Investment Plan you have to name your spouse as your beneficiary, unless you get your spouse's written notarized consent to name someone else.
Note: Domestic partners are not treated as spouses under the tax law or for purposes of the 401(k) Savings & Investment Plan.
However, the US Retirement Program does provide survivor benefits to qualified domestic partners. See "Eligible Survivor" in the Marsh & McLennan Companies Retirement Plan, Benefit Equalization Plan and Supplemental Retirement Plan sections of the Benefits Handbook for specific domestic partner plan details.