Employee vs. Employer Contributions
In most 401(k) plans, employees make elective deferrals, while employers might match a portion of those contributions. In divorce, a common mistake is awarding 50% of the total balance without clarifying which contributions are subject to division.
Best practice: Award 50% (or another percentage) of the marital portion—typically defined as the contributions made and gains/losses accrued during the marriage. Unless otherwise agreed, employer contributions should be included only if vested.

