Employee Contributions vs. Employer Contributions
In most 401(k) plans, employee deferrals are always 100% vested, which means the participant owns those amounts outright. However, employer contributions often come with a vesting schedule—this is crucial in calculating the amount the alternate payee is entitled to.
Unvested amounts at the time of divorce are usually excluded from the division unless the employee later vests fully. Your QDRO must clearly state how to treat unvested portions, or disputes can arise during payout.

