Your TSP beneficiary designation overrides your will. It doesn't matter what your estate documents say — whoever is listed on Form TSP-3 receives those funds. And unlike an IRA, the TSP comes with its own set of inheritance rules that can catch even well-prepared families off guard.

For military members and federal employees, the TSP is often one of the largest assets in an estate. Getting the beneficiary designation right — and understanding how your heirs will be treated under TSP rules — is one of the most important (and most overlooked) steps in a complete financial plan.

In this post, we cover the most common TSP beneficiary mistakes, how TSP inheritance rules differ from IRA rules in ways that matter for your family, and what questions are worth taking to your financial planner before it's too late to course-correct.