What a real interest rate is

A nominal interest rate is the number on the screen: the 10-year US Treasury yields 4.96%. A real interest rate is what is left after inflation takes its share. If a bond pays 5% and prices rise 3%, your purchasing power grows by about 2%. That 2% is the real rate, and it is the one that decides whether holding cash and bonds actually makes you richer.

The cleanest market measure comes from TIPS, Treasury bonds whose principal is indexed to inflation. Their yield is a real yield directly, set by buyers and sellers every day. The 10-year TIPS yield is published by the Federal Reserve as series DFII10, and it is the number this article uses.

Subtract it from the ordinary 10-year yield and you get the breakeven inflation rate: the inflation the bond market expects over the decade.

MeasureLatest reading
10-year Treasury yield, nominal4.96%
10-year TIPS yield, real2.63%
10-year breakeven inflationabout 2.33%

So investors are being offered about 2.6% a year above inflation, guaranteed by the US government, for ten years. That is the bar every other asset has to clear.

The highest since November 2008

On September 16, the day the Federal Reserve raised rates for the first time since 2023, the 10-year real yield closed at 2.68%. The last time it was that high was November 26, 2008, in the middle of the financial crisis.

Date10-year real yield10-year nominal
Dec 31, 2021negative 1.04%1.52%
Oct 19, 20232.49%4.98%
Dec 31, 20251.93%4.18%
Jun 30, 20262.20%4.44%
Sep 16, 2026, Fed hike day2.68%
Latest2.63%4.96%

Read the first row carefully. At the end of 2021 the real yield was negative: lending to the US government for a decade guaranteed you would lose purchasing power. Since then it has risen by about 3.7 percentage points, one of the fastest swings in the history of the series.

What the textbook says should happen

Gold pays nothing. Bitcoin pays nothing. Holding either means giving up the yield you could have earned in a bond, and that sacrifice is called the opportunity cost. When real yields are negative, the cost of holding gold is zero or better, because the bond would have lost you money anyway. When real yields are high, you give up a guaranteed return above inflation to hold a metal.

So the textbook relationship is simple: real yields up, gold down. For most of the 2010s it held remarkably well, and the same logic has been applied to Bitcoin as a non-yielding store of value.

By that logic, a move from negative 1.04% to 2.63% should have been brutal for both. Here is what happened instead.

AssetDec 31, 2021Sep 23, 2026Change
10-year real yieldnegative 1.04%2.63%up 3.67 points
Gold, per ounce, via PAXG$1,835$4,288+134%
Bitcoin$46,217$84,398+83%

The largest rise in real yields in a generation, and gold more than doubled.

What five years of weekly data actually show

Levels over five years can hide a lot, so we measured the short-term relationship too. For every week since January 2021, 298 in all, we compared the change in the 10-year real yield with the return on gold and on Bitcoin that same week.

AssetCorrelation since 2021Correlation since 2024
Goldnegative 0.22negative 0.07
Bitcoinnegative 0.08negative 0.07

A correlation of negative 1 would mean the textbook holds perfectly; zero means no relationship. Gold still leans the textbook way, but weakly, and the lean has almost vanished since 2024. Bitcoin has barely leaned at all.

The sharpest test is the big weeks. Across the 32 weeks when the real yield rose 15 basis points or more, and the 15 weeks when it fell that much:

Week typeGold, mean weekBitcoin, mean week
Real yield up 15bp or more, 32 weeksnegative 0.36%+0.31%
Real yield down 15bp or more, 15 weeks+1.77%, positive 73% of the timenegative 1.10%
Everything in between, 251 weeks+0.30%+0.69%

Gold behaves as the textbook predicts in the big weeks, just not by much. Bitcoin does the opposite of the textbook on the big falls in real yields, on a sample of 15 weeks, which is too small to build a theory on and large enough to stop anyone claiming Bitcoin trades as a real-yield instrument.

Why the textbook broke

Nobody can prove the cause, but three explanations are widely discussed and all three are consistent with the numbers above.

Central banks became the marginal buyer of gold. After Russia's reserves were frozen in 2022, several central banks increased gold holdings for reasons that have nothing to do with the yield on a TIPS bond. A buyer that ignores real yields weakens the relationship.

Fiscal worry replaced inflation worry. High real yields driven by heavy government borrowing are a different signal from high real yields driven by a tight central bank. The first can raise demand for assets outside the financial system at the same time as it raises the yield on bonds.

Bitcoin found new buyers. Spot ETFs, corporate treasuries and a changing regulatory picture drove large flows that had little to do with the opportunity cost of holding it.

The practical lesson is narrower than any of these stories. Real yields are one input, not the lever. They still tell you what a risk-free investment pays above inflation, which matters for every savings and investment decision. They no longer tell you, on their own, what gold or Bitcoin will do next week.

How to use this yourself

Check the real yield, not just the headline rate. A 5% savings rate with 4% inflation is a 1% real return; a 3% rate with 1% inflation is 2%. The second is better, even though it looks worse.

Know where to find it. The Federal Reserve Bank of St. Louis publishes DFII10 free every business day. Breakeven inflation is series T10YIE.

Treat any single-factor story with suspicion. Five years ago "real yields up means gold down" was treated as close to a law. The data above shows why no one variable should carry that much weight, including the ones on this site.