Treasury Securities
Direct obligations of the U.S. government: T-bills (one year or less, sold at a discount), T-notes (2–10 years), T-bonds (over 10 years), TIPS (principal adjusts with CPI), and STRIPS (zero-coupon Treasuries).
Treasury interest is taxable federally but exempt from state and local tax — the mirror image of municipal bonds. Treasuries carry essentially no credit risk, which is why their yields anchor the yield curve, but they remain fully exposed to interest-rate and inflation risk.