Take the portion you want to protect with least risk, divide it into $250K chunks (the FDIC limit) and put each in a savings account with a different bank. You

Take the portion you want to protect with least risk, divide it into $250K chunks (the FDIC limit) and put each in a savings account with a different bank. You'll make a small interest rate and you'll have FDIC insurance covering the entire amount. That's safer than any of the Treasury securities since you will still have the backing of the US government, you can use it to rebalance your portfolio at any time, and you don't have interest rate risk. This is one area where you have an advantage over the big players like Pimco, who can't protect themselves with FDIC insurance.