There are many ETFS which can be purchased in lieu of bank CDs.
and you can play the yield curve better than you can at your bank.
Just a moment... lists treasury bill, notes and bonds ETFs which invest in US treasuries, and is more tax efficient than bank interest instruments (there are capital gains involved when interest rates drop for additional returns)
Playing the field curve:
currently short term bills have a higher interest rate than notes and bonds.
Eventually they will drop in rates, and once they go lower than the 5-7 year Treasury ETF, you switch and get higher rates for longer with longer notes.
In addition you get capital appreciation when interest rates go down in addition to higher rates while the older bills/notes are held and slowly get replaced by newer issues.
maximize returns versus maximizing safety with the US government instruments, guaranteed to return the instruments's face value.
good luck