Employee vs. Employer Contributions
Employee contributions to a 401(k) are fully owned by the participant, but employer matching contributions often follow a vesting schedule. That means a portion of the employer-funded account may not be available for division during divorce if it’s not yet vested.
Your QDRO should clearly distinguish between what portion of the balance is employee-contributed (which can usually be divided right away) and the employer match (which may or may not be 100% vested). Distribution of only the vested portion can be protected in the QDRO language.

