Employee vs. Employer Contributions
In most 401(k) plans, both the employee and the employer may contribute. During divorce, only the marital portion—typically contributions made from the date of marriage to the date of separation—is subject to division.
Employer contributions often have vesting rules. If the participant is not fully vested in the employer’s contributions, then only the vested portion is available for division. The QDRO should explicitly account for whether the alternate payee receives a portion of these employer contributions—and if so, whether that share is limited to vested amounts only.

