MMC Benefits Handbook
Grandfathered BEP Benefit
At the time that Section 409A was enacted, employers were permitted to "grandfather" (thereby exempting) non-qualified benefits accrued and vested before January 1, 2005, provided the benefit is paid pursuant to plan terms that were in effect on October 3, 2004 under prior tax rules thereby exempting them from the rules imposed by Section 409A. Marsh McLennan took steps to secure grandfathered treatment for those BEP benefits.
If you had a vested BEP benefit on December 31, 2004, a portion of your BEP benefit is grandfathered.