Employee Contributions vs. Employer Contributions
Employee contributions made to a 401(k) are typically 100% vested, meaning they belong entirely to the employee and are subject to division through a QDRO. However, employer contributions might be subject to a vesting schedule.
If your spouse has worked for the employer for only a short time, a portion of the employer matching or profit-sharing contributions might not be vested. Only the vested portion is divisible in a divorce. Unvested employer money is typically forfeited when the employee leaves the employer before completing the vesting schedule.
Your QDRO must distinguish between vested and unvested balances correctly so that everyone understands what portion is available for distribution.

