Investing is about balancing risk and reward. Any good investment will typically allow for nominal risk for a healthy return, but let's suppose that's not what I'm looking for. I want something with no risk, provided no armageddon-like scenarios (US defaults on debt, government collapse, etc.) occur. I might invest in CD's which max out around 1%, T-bonds which max out around 2%, and some FDIC-backed savings accounts offer yields up to 2.5%.
What is the highest-return investment with functionally zero risk?