MMC Benefits Handbook
Transfers from Non-Participating MMA and Marsh McLennan
If you transfer from a company that does not participate in the Plan (for example, a Mercer company) to one that does, you are eligible to join the Plan as of the first available pay period after you enroll, provided you otherwise meet the Plan's eligibility requirements. If you have at least one year of service with a Marsh McLennan or MMA company at the time of the transfer, you will be eligible to receive Company matching contributions as soon as you start making contributions to the Plan.