Employee and Employer Contributions
In 401(k) plans, employees contribute pre-tax (or post-tax in the case of Roth 401(k)s) dollars from their paycheck. Employers often match a portion of those contributions, but these contributions may be subject to a vesting schedule. Contributions made by the employee are 100% in their control and available for division. However, employer contributions may not be fully vested at the time of divorce and can become a major point of discussion in the QDRO.

