When the US Treasury Rate rises so will yours! As a variable rate CD, the interest rates will change the first Wednesday of every month. The 90 day rate will be based on the 91-Day US Treasure Rate. The 30 day rate will be based on 80% of the 91-Day US Treasury Rate. $2,500.00 is minimum amount to open and keep certificate of deposit. A penalty will be imposed for a withdraw of initial deposit. F.D.I.C. insured to maximum allowed by law.