As other have mentioned, it's not "risk free" in a way that makes it "insane". You could buy a 10-year bond paying 8% in 1970. That's a high yield by 21st-cent

As other have mentioned, it's not "risk free" in a way that makes it "insane". You could buy a 10-year bond paying 8% in 1970. That's a high yield by 21st-century standards but it performed quite poorly [1]: when you got your principal back ten years later it was worth less than half as much due to inflation (and not even by reinvesting the interests received would you break even). [1] not worse than stocks, though