June 5, 2019 10:37 PM
The 50K could be agency funds or growth in the investments, both are taxable in this situation. Unless your investments lost money (?) a portion is investment gains that are taxable. You can't assume that the entire amount was only your contributions, there likely is investment gains included in the total. You should have seen gains (and a few losses) in your investment on each quarterly statement that you received. BTW, CSRS retiree here with a TSP. I haven't contributed in 15 years but my TSP has steadily grown in value.