Case study: the US 10-year Treasury

"Risk-free" means default-free only: the 10-year carries enormous price risk from duration, which 2022 proved by handing holders of long Treasuries a roughly 30% loss as a four-decade bond bull market ended.

The yield on the US 10-year Treasury note is the most important number in finance: the risk-free rate in nearly every valuation model on earth, the global benchmark for mortgages and corporate borrowing, and the asset the whole system flees to in a crisis. Studying it teaches bond mechanics with the cleanest possible instrument, and its recent history delivered the most expensive lesson in duration that a generation of investors will ever get.

The short version

A Treasury is a fixed stream of coupons plus principal, so its price and yield are two readings of one present-value equation: when yields rise, prices of existing bonds fall, and the longer the maturity, the harder (that sensitivity is DURATION). The 10-year is "risk-free" only in the narrow sense of default: it carries enormous PRICE risk, which 2022 proved by handing holders of long Treasuries a ~30%+ loss in the safest asset in the world, as a four-decade bull market in bonds ended. Professionals read the 10-year for its real yield and inflation breakeven, and read the yield CURVE as the market's growth-and-policy forecast.

Why the 10-year specifically

It sits at the center of everything. It is long enough to embody the market's view of growth, inflation and policy over a meaningful horizon, but liquid enough to trade in size instantly; it is the discount-rate reference in the equity models of the valuation track (the risk-free rate in CAPM); it prices the 30-year mortgage and anchors corporate spreads; and it is the world's reserve collateral. When people say "rates went up," they usually mean this. Understanding the 10-year is understanding the denominator of the entire market.

Anatomy of the security

A 10-year note, priced

face value $1,000, coupon 4%, paid semi-annually, 10 years to maturity

price = sum of ($20 every 6 months) / (1 + y/2)^t  +  $1,000/(1+y/2)^20

if the market demands y = 4%: price = $1,000 (par)
if y rises to 5%:            price ≈ $922   (-7.8%)   <- DURATION ~7.8
if y falls to 3%:            price ≈ $1,086 (+8.6%)   <- and convexity:
                                          the gain exceeds the loss slightly

Everything about bonds lives in that box. Yield to maturityis the single rate that makes the promised cash flows worth today's price: the bond's IRR. Duration (~7.8 here) is the price sensitivity to a 1% yield change, and it grows with maturity: a 30-year Treasury has duration near 20, which is the whole story of 2022. Convexity is the small favorable curvature: prices rise a touch more than they fall for equal yield moves, an asymmetry the market pays a little for.

The 40-year bull market (1981-2020)

Period	10-year yield	What it meant
1981	~15.8% (the peak)	Volcker's war on inflation; the greatest bond entry point in history
1990s	~5-8%	Disinflation; the 'bond vigilantes' era; a steady tailwind for all assets
2008-2015	~2-4%, then lower	GFC and QE; central banks as buyers; the reach for yield begins
2020	~0.5% (the low)	COVID: the 40-year bull's final gasp; ~$18T of global bonds at NEGATIVE yields

For forty years, yields fell, which meant bond prices ROSE, which meant that owning long Treasuries was not just safe but profitable, and an entire generation of investors and models internalized bonds as a reliable ballast that made money when stocks fell. The 60/40 portfolio worked beautifully because both halves compounded. That experience was true, and it was a regime, not a law, a distinction 2022 made painfully.

2022: duration made real

How the safest asset lost a third of its value

start 2022: 10-year yield ~1.5%, 30-year ~2%
inflation surges; the Fed hikes from ~0% to ~4.4% in one year
end 2022:   10-year ~3.9%, 30-year ~4%

a long-duration Treasury index (20+ yr), duration ~18:
  ~2% yield rise x ~18 duration  ≈  -30%+ price loss IN ONE YEAR

and the co-lesson: bonds fell WITH stocks (the 60/40 had its worst
year in a century) because the shock was INFLATION, which flips the
stock-bond correlation the macro guide describes. The ballast sank
with the ship.

The most expensive word in bonds: 'safe'

Long Treasuries are default-risk-free and were, in 2022, the WORST major asset class to own. The two facts do not conflict: "risk-free" refers to getting your coupons and principal as promised, IF HELD TO MATURITY. It says nothing about the price along the way, and a 30-year bond held for one year is a pure duration bet. The generation that learned "bonds are safe" from 1981-2020 learned the wrong lesson from a falling-rate regime; the accurate lesson is that a bond's risk is its DURATION, and long duration is a large bet on rates whatever the credit quality.

Reading the curve: the market's forecast

The 2s10s spread (2-year vs 10-year yield) is the headline curve gauge. Normally positive (longer money costs more); when it INVERTS (2-year above 10-year), the market is pricing rate cuts ahead, which historically means it expects a slowdown. The 2022-2024 inversion was the deepest in decades and preceded the era's central recession-or-not debate.
Real yield vs breakeven. Split the 10-year into the TIPS real yield and the inflation breakeven. Gold and long-duration equities trade off the REAL yield; the breakeven is the bond market's live inflation forecast. In 2022 real yields did the damage; the breakeven stayed comparatively anchored, telling analysts the move was policy, not runaway inflation expectations.
The term premium. The extra yield for bearing duration risk, compressed by years of QE and debated endlessly; its re-emergence is part of the post-2022 higher-rate regime.
Supply matters now. Large fiscal deficits mean heavy Treasury issuance; who buys (foreign reserves, the Fed, price-sensitive domestic buyers) became a live analytical question after the reliable central-bank bid receded.

What "risk-free" actually means

The Treasury is the benchmark because the US government can always create the dollars it owes, so nominal DEFAULT is not the risk. What remains is real, and considerable: price/duration risk (2022), inflation risk (the coupons are fixed; high inflation erodes their purchasing power: the 1970s destroyed real bond returns even without default), reinvestment risk, and, increasingly discussed, the fiscal and political questions around debt sustainability and debt-ceiling brinkmanship. "Risk-free" is a precise, narrow technical term, and the valuation models that lean on it should be read knowing exactly how narrow.

The transferable lessons for any bond

Price and yield are one equation. Internalize the seesaw until it is reflex; every bond headline is a restatement of it.
Duration IS the risk. A bond's sensitivity to rates, set by its maturity and coupon, is the position's real size: a "safe" 30-year is a large macro bet.
Regimes are not laws. Forty years of falling rates taught a lesson that one year reversed; test whether a comfortable relationship is structural or just the current regime.
Split the yield. Real yield plus breakeven tells you WHAT moved rates, which decides what else in the portfolio is affected.
The curve is a free forecast. Inversions, steepenings and the real/breakeven split are the market's own macro view, published continuously (the macro guide reads it too).
Match duration to purpose. Income, ballast, and dry powder are different jobs needing different maturities; holding long duration for "safety" is the category error 2022 punished.

Glossary for this guide

Yield to maturity: The single rate that makes a bond's remaining coupons and principal worth exactly its current price: the bond's IRR if held to the end and paid in full.
Coupon: The fixed interest payment a bond makes, named for the paper coupons holders once clipped. Set at issue; what changes afterwards is the price, and therefore the yield.
Duration: A bond's price sensitivity to interest rates: duration 7 means roughly a 7% price fall per one-point yield rise. The dial bond managers use to set how much rate risk a portfolio carries.
Convexity: The curvature duration misses: bond prices fall less and rise more than the linear estimate. A small free asymmetry in the holder's favor, priced accordingly.
Yield curve: Government yields plotted against maturity. Upward-sloping is the normal state; its shape is the bond market's forecast of growth, inflation and policy.
Inverted curve: Short yields above long ones: the market pricing future rate cuts, which usually means it expects a slowdown. It has preceded most postwar US recessions, with long and variable lead times.
Real interest rates: Nominal rates minus expected inflation: the true price of money. The main driver of gold (the opportunity cost of a yieldless asset) and, in liquidity-driven regimes, of most risk assets.
Breakeven inflation: The bond market's inflation forecast: the nominal government yield minus the inflation-protected (TIPS) yield of the same maturity. What inflation-hedging assets are priced against.
Risk-free rate: The yield on the safest asset in the currency of the cash flows, in practice a long-term government bond. It is the floor every other required return builds on.
Stock-bond correlation: In low-inflation regimes bonds hedge stocks (bad growth news brings rate cuts); in high inflation the correlation flips positive and the classic 60/40 loses both halves at once, as 2022 demonstrated. Which regime you are in decides whether your diversification exists.
Nominal vs real: Nominal counts dollars; real counts purchasing power, which is nominal with inflation removed. The rule: discount nominal cash flows at nominal rates and real at real, never mixed.
Basis point: One hundredth of a percentage point. Spreads and fee schedules are quoted in it; 50 basis points is half a percent.