Employee and Employer Contributions
In most 401(k) plans, employee contributions are 100% vested immediately, but employer contributions may be subject to a vesting schedule. In divorce, only the portion that is vested as of the cutoff date (often the date of separation or divorce) can be divided by a QDRO.
If the employee is not fully vested, unvested portions will eventually revert back to the plan if the employment ends before full vesting. This is critical—allocating a share of unvested funds in a QDRO can cause confusion and enforcement issues later.

