Employee vs. Employer Contributions
With a 401(k), the participant’s own contributions are always considered fully vested and available for division. However, employer contributions may be subject to a vesting schedule, meaning your spouse may not be entitled to all employer contributions unless they’ve met certain service milestones.
Your QDRO must clearly state whether unvested employer funds are included in the division. In most situations, only vested values can be assigned to an alternate payee (the non-participant spouse).

