It’s almost certain that the cap on regular investments in the TSP will remain at $18,000 and that the limit on “catch-up contribution” investments—additional investments allowed for those 50 or older in a calendar year who make the full regular investment—will remain at $6,000. The IRS has not made a formal announcement regarding those limits, which are the same as for all similar retirement savings programs such as 401(k)s, but they rise only after accumulated inflation since the previous increase has exceeded a certain level. The limits apply to the total of traditional pre-tax investments and after-tax Roth investments, for those making both types; they don’t include agency contributions on behalf of FERS-covered employees or rollovers from similar plans of prior employers.