Employee and Employer Contributions
The Arctera 401(k) Plan likely includes contributions made by the employee (your spouse or former spouse) and matching or profit-sharing contributions from Arctera us LLC. While all employee contributions are immediately vested, employer contributions may be subject to a vesting schedule.
In a divorce, your share is typically limited to the vested portion. For example, if 50% of employer contributions are vested at the time of divorce, then only that 50% is eligible for division via QDRO. The QDRO must reflect these limitations clearly to avoid payment disputes.

