5 CFR §1650.60

1. (a)A participant or beneficiary participant may request up to a maximum of 26 Roth in-plan conversions per calendar year.
2. (b)To be eligible for a Roth in-plan conversion, the participant or beneficiary participant must have a vested account balance of at least $500 at the time of the request.
3. (c)The total amount of a conversion request must be at least $500.
4. (d)Participants must retain at least $500 in each of their tax-deferred employee contribution, tax-exempt contribution, agency automatic (1%) contribution, and agency matching contribution balances.
5. (e)Amounts invested in the Mutual Fund Window cannot be converted unless those amounts are first transferred back into one or more of the TSP core funds.
6. (f)Administrative holds placed pursuant to § 1690.15 will restrict an individual from requesting a Roth in-plan conversion.
7. (g)The TSP record keeper shall promptly notify the participant or beneficiary participant if their Roth in-plan conversion request is denied.