By Jim Dahle , WCI Founder Starting in 2026, the Federal Thrift Savings Plan (TSP) began allowing in-plan Roth conversions. Think of the TSP as the 401(k) for federal employees, including military members. The TSP has traditionally been relatively slow to adopt newly allowed 401(k) features. For example, it didn't start allowing Roth contributions at all until May 7, 2012, long after I had separated from military service. That's 11 years after Roth 401(k) contributions were allowed. Likewise, in-plan conversions were first allowed in 401(k) plans in 2010, but it took until 2026 before the TSP got up to speed. At any rate, TSP participants can now do as many as 26 in-plan Roth conversions every year, although they cannot yet be automated. The TSP won't withhold taxes on conversions either, but that issue is easily dealt with, if necessary, by changing withholdings or just making quarterly estimated payments as needed.…