When I googled Negative rates. From Feb 18 2016 What Would Happen to the TSP if Interest Rates Turned Negative? Michael Wald February 18, 2016 https://www.fedsmith.com/2016/02/18/what-would-happen-to-the-tsp-if-interest-rates-turned-negative/ G Fund No Longer Keeping Up with Inflation Published: February 18, 2020 https://www.fedweek.com/tsp/g-fund-is-no-longer-keeping-up-with-inflation/