EE bonds earn interest until they reach 30 years or until you cash them, whichever comes first. You can cash them after 1 year. But if you cash them before 5 years, you lose the last 3 months' interest. (For example, if you cash an EE bond after 18 months, you get the first 15 months of interest.)

Do EE bonds earn interest after 30 years?

The bond continues to accrue interest even after reaching its face value, but at “final maturity” (after 30 years) interest stops accruing and must be reported. Note: Interest on EE savings bonds isn't subject to state income tax.

Is there a penalty for not cashing in matured EE savings bonds?

Even though the Treasury doesn't care if you cash in your fully matured savings bond, the tax rules require you to declare the interest you have earned and pay taxes on it. ... If you failed to report the interest for the year the bond matured, you are liable for any taxes due and possibly a tax penalty.