Employee vs. Employer Contributions
The employee’s own salary deferrals (pre-tax or Roth) are generally 100% theirs. However, employer matching or non-elective contributions often follow a vesting schedule. If your divorce is finalized before all employer contributions are fully vested, the non-vested amounts may be off-limits to the alternate payee (the non-employee spouse).
A well-drafted QDRO will address exact percentages or set values, account for available balances, and reference the vesting status on the date of division (usually the date of divorce or account valuation).

