Treasury Bond

What Are Treasury Bonds?

Treasury bonds (T-bonds) are US government debt securities with original maturities greater than 10 years. Currently the Treasury issues 20-year and 30-year T-bonds. The 30-year is colloquially known as "the long bond" and has historically been the highest-profile Treasury security despite lower trading volumes than the 10-year.

T-bonds pay semi-annual coupons and return face value at maturity. They are auctioned monthly: 20-year bonds on a regular cycle launched in May 2020; 30-year bonds on a regular monthly cycle that has been in place for decades. Reopenings of existing CUSIPs alternate with new issues.

FRED tickers include DGS20 (20-year) and DGS30 (30-year).

Why T-Bonds Matter

T-bonds are the highest-duration Treasury securities and the primary instrument for expressing views on long-term interest rates. The 30-year T-bond at par has modified duration of approximately 17-18 years, meaning every 100 bp move in yield produces approximately 17-18% price moves in the opposite direction.

The long bond yields anchor:

• Pension liability discounting: Many corporate and public pensions discount future obligations using 30-year Treasury yields. Higher long-bond yields reduce liabilities.
• Long-tail insurance reserves: Life insurance reserves are partly tied to long-bond yields.
• Mortgage-backed security duration: MBS pricing involves option-adjusted spreads to the Treasury curve, with long-end yields critical for fixed-rate mortgage valuations.
• Sovereign credit signaling: Sustained long-bond yield rises (especially via term premium) can signal market concerns about US fiscal trajectory.

How to Read Long-Bond Yields

30-year vs 10-year spread. The 30-10 spread captures term premium dynamics. A widening spread signals term premium expansion (often fiscal-supply-driven); a narrowing spread signals term premium compression (often Fed-easing-driven).

Auction tails. As with T-notes, the auction "tail" (high accepted yield minus prevailing market yield) signals demand strength. 30-year auction tails are watched especially closely because of the long bond's role as a fiscal-credibility barometer.

Real 30-year yield. The 30-year Treasury minus 30-year breakeven inflation gives the real 30-year yield, which captures genuinely structural real-rate dynamics.

Long bond as a stress signal. The 30-year crossing 5% (first time since 2007) in October 2023 was a major macro event, signaling that term premium had expanded substantially and fiscal-supply concerns were re-entering the price.

Historical Context

The 30-year T-bond yield has ranged from a low of 0.99% (March 2020) to a high of 15.21% (October 1981). The 2010-2019 expansion saw it range between 2.1% and 4.4%. The 2022-2023 cycle drove it from 2.0% in early 2022 to 5.1% in October 2023.

The 20-year was reintroduced in May 2020 after a 33-year hiatus. The 20-year typically trades between the 10-year and 30-year yields; the 20-year minus 10-year spread reflects intermediate-term term premium dynamics.

Through 2024-2025, the 30-year has run in the 4.0-4.9% range, somewhat tighter than the October 2023 peak but well above the 2010s average. The persistent positive 30-10 spread reflects the term-premium expansion that has been a defining feature of the post-2022 cycle.