5 CFR §1601.22

1. (a)Participants may make a fund reallocation in the form and manner prescribed by the TSP record keeper. Paragraphs (a)(1) and (2) of this section apply to a fund reallocation request:
   1. (1)Fund reallocation requests must be made in whole percentages (one percent increments). The sum of the percentages elected for all of the TSP core funds must equal 100 percent.
   2. (2)The percentages elected by the participant will be applied to the balances in each source of contributions and to both traditional and Roth balances and tax-deferred and tax-exempt balances on the effective date of the fund reallocation.
2. (b)A fund reallocation request has no effect on deposits made after the effective date of the fund reallocation request; subsequent deposits will continue to be allocated among the TSP core funds in accordance with the participant's investment election made under subpart B of this part.
3. (c)If a fund reallocation is found to be invalid pursuant to § 1601.34, the purported fund reallocation will not be made.