1. Employee and Employer Contributions
401(k) accounts contain both employee deferrals (the money the participant personally contributed) and employer contributions. Whether the plan offers matching or profit-sharing, the value of the employer’s share may be subject to a vesting schedule. That means portions of the account may not fully belong to the participant yet—and might be forfeited if employment ends.
If the participant hasn’t met the vesting requirements, the QDRO should only assign the marital share of the vested balance. Otherwise, the alternate payee may receive nothing.

