re: Investing Emergency Fund?

I wouldn't consider an emergency fund as a potential income source like you would would regular cash. Don't look at not investing as a lost opportunity.

The purpose of the fund is to protect you. The "risk" should be how small are you willing to go with your emergency fund. What you have determined you "need" go savings or CD. I put a big chunk of my EM fund in a 2.25% CD a while back. I'll do more CDs when the rates start going up soon.