Employee vs. Employer Contributions
In a 401(k), employees typically contribute a portion of their income on a pre-tax or Roth basis. Employers may match some of those contributions. A QDRO can divide just the employee contributions, only the employer contributions, or both—so long as the language is clear.
However, employer contributions are almost always subject to a vesting schedule. That means even if the balance appears high on paper, part of that may be unvested and thus not eligible to be divided.

