Treasury bonds (T-bonds), notes (T-notes), and bills (T-bills) are government-issued fixed-income securities that are very low risk. T-bonds typically mature in 20 or 30 years and offer the highest coupons or interest, which are paid twice yearly. T-notes mature from two to 10 years, with semiannual interest payments but usually lower yields than T-bonds. T-bills have the shortest periods before maturity, from four weeks to a year. https://www.investopedia.com/ask/answers/033115/what-are-differences-between-treasury-bond-and-treasury-note-and-treasury-bill-tbill.asp#:~:text=T%2Dbonds%20typically%20mature%20in,four%20weeks%20to%20a%20year.
Local tax也有10%
https://www.investopedia.com/ask/answers/033115/what-are-differences-between-treasury-bond-and-treasury-note-and-treasury-bill-tbill.asp#:~:text=T%2Dbonds%20typically%20mature%20in,four%20weeks%20to%20a%20year.
I bond现在利息也没有太好了，还是买Tbill方便，但这俩都是bond
i-bond adjusts the interest rate every six months according to inflation rate.