Employee vs. Employer Contributions
Employee contributions to the 401(k) plan are typically considered fully vested and are divisible during divorce. However, employer contributions might be subject to a vesting schedule. If the employee spouse has not met the vesting requirements at the time of divorce, part of the employer contributions may not be divisible.
This distinction between vested and unvested funds must be clearly accounted for in a properly drafted QDRO. Otherwise, the alternate payee may expect more than they’re legally entitled to receive.

