While bond investments can lose value if interest rates increase, you lock in a return if you hold the bonds until they mature. The problem is that you don’t know when you’ll need your emergency money and might not be able to wait until your bond investments mature.
This is fixed with a Laddered Bond Investment Strategy where you invest in bonds with different maturities. This is a strategy we talked about in our Guide to Bond Investing and is a strategy that most should use even if they are not using bonds for their emergency fund savings.