Employee vs. Employer Contributions
401(k) accounts usually contain both employee (participant) contributions and employer contributions. Any amounts earned during the marriage are typically subject to division unless a prenuptial agreement says otherwise.
Employer contributions may be subject to a vesting schedule. That means a portion of those contributions may not be considered the employee’s property if they leave the company too soon. Only vested portions can be awarded in a QDRO. It’s critical to clarify which amounts are vested and include that in the order.

