Vesting Schedules and Unvested Funds
401(k) plans often include employer match contributions that are subject to vesting. If the employee (your former spouse) hasn’t met certain service requirements, part of the employer contributions may not yet be fully owned. The QDRO should clearly state whether you are entitled to just the vested portion or any future vesting as well.
Important tip: If your QDRO attempts to award unvested funds without clarification, the administrator may reject the order outright.

