Employee and Employer Contributions
401(k) plans typically consist of both employee contributions (your spouse’s deferrals) and employer-matching funds (if applicable). You may be entitled to a share of both, depending on when they were earned in relation to the marriage.
Keep in mind that employer contributions may be subject to a vesting schedule. This means not all employer-funded amounts may be accessible if your spouse hasn’t worked at the company long enough. If there are unvested amounts at the time of divorce, they usually do not transfer to you under a QDRO.

