I honestly had no idea those Fidelity index funds existed with such low fees. Very surprised the life cycle funds are also so low. Honestly seems too good to be true (investigation pending), but assuming they are accurate and they aren't teaser rates that will go up, there may be little reason to stay in TSP. My fear would be that the rates won't stay low and one would have no way to get back in to TSP.

There will always be folks leaving non-vested funds behind when leaving federal service, and that money keeps TSP fees relatively low. I don't have a whole lot of faith that Fidelity won't try to take as much of my money as possible... any idea how long SP500 index fees have been held down to .01%?