The real yield is 2.18 — and that is the number that shapes decisions

Last Thursday, May 21, the 10-year Treasury yielded 4.57%. That is the nominal yield — the number you get back if you lend the government your money for ten years, before inflation eats any of it.

On the same day, the 10-year TIPS — the inflation-protected version of the same instrument — yielded 2.18%. That is the real yield, the part of your return the government has agreed to pay you on top of whatever inflation turns out to be over the next ten years.

The difference between the two, 2.39 percentage points, is the market's implied expectation of average annual CPI inflation over the next decade. FRED publishes that one pre-computed too, as T10YIE — its reading on Friday May 22 was 2.40, which matches my subtraction to within a basis point.

This post is about the 2.18 number, which I think is the most underrated single figure in the U.S. rates complex. Nominal yields get all the headlines. Real yields are what actually shape decisions.

What DFII10 actually is

The series ticker is DFII10 — "Daily, Federal Reserve, Inflation-Indexed, 10-year." It is the constant-maturity yield on Treasury Inflation-Protected Securities at the 10-year point, the TIPS counterpart of DGS10.

A TIPS works like this: the principal of the bond is adjusted up (or down) each month based on CPI. The coupon rate is fixed, but it pays out on a principal that grows with inflation. If you hold to maturity, you get back your original principal adjusted for cumulative CPI, plus the fixed coupon stream applied to that growing principal.

The yield quoted on DFII10 is therefore the real yield — what the holder earns above CPI. If you buy a 10-year TIPS at a 2.18% yield and CPI averages 3% a year for the decade, your nominal return is roughly 5.18%. If CPI averages 1%, your nominal return is roughly 3.18%. The 2.18 is the part that doesn't move when inflation surprises you.

This is the cleanest measure of "what is the actual cost of capital, stripping out the inflation that everyone is arguing about?" — and it is the input that matters most for almost every long-duration valuation problem.

The history matters here

When I pulled DFII10 back through its history, the regime change shows up clearly:

• 2003–2008 (early TIPS era): real yields averaged near 2%. Normal. Savers got paid a real return for holding long-duration government debt.
• 2012–2021: real yields were mostly at or below zero. The 10-year real yield spent meaningful stretches at −1%. The government was effectively paying you to lose purchasing power slowly, which is the technical condition that drove the "there is no alternative" equity story.
• 2022–2024: the regime broke. Real yields climbed from near −1% to roughly +2% in about eighteen months — the fastest move in the series' history.
• Now (May 2026): 2.18, sitting in the upper half of the pre-2008 distribution and above almost every observation between 2010 and 2022.

The 60 trading days I have cached locally tell the recent half of that story in miniature. On February 27, DFII10 was 1.72. On May 21, it was 2.18. That is 46 basis points of real-yield rise in under three months, which is a lot. Over the same window the nominal 10-year rose by a similar magnitude, and the breakeven inflation series T10YIE barely moved — it sat in a tight band around 2.3–2.4 the whole time. The conclusion that follows from those three series together is precise: almost the entire recent rise in nominal yields has been real, not inflationary. The market is not pricing in more inflation. It is pricing in a higher real discount rate.

That distinction does not survive most headline coverage, which tends to report "yields up" as if there were one number rising. There are two numbers, and which one is doing the work tells you what the move actually means. When I read a piece that talks about a yield move without naming whether the real or the breakeven component drove it, I treat it the way I treat a stock-price story that doesn't say whether earnings or the multiple moved — half the relevant information is missing, and I have to go look it up myself before I can decide what to think.

Why this is the number that shapes decisions

Three concrete examples of where the real yield, not the nominal, is the input that drives the answer.

1. Equity valuation. The standard discounted-cash-flow model values a stream of future cash flows by discounting them back at a real rate. If your discount rate goes from −0.5% to +2.0%, the present value of a dollar received twenty years out falls by roughly a third. That is a structural headwind for any business whose value is concentrated in the back of the projection — most growth and tech equities, most early-stage venture, most infrastructure with long payback. It is also a tailwind for businesses whose value is front-loaded — mature cash cows, dividend-payers, anything where the next few years dominate the DCF. A move from negative-real to positive-real real yields is the single best one-line explanation for the relative performance of value vs. growth since 2022.

2. Housing affordability. A mortgage rate is, very roughly, the 10-year Treasury plus a spread (the spread story is what D1 covered). But the real mortgage rate — the rate you pay above expected wage and price inflation — is what determines whether the payment becomes more or less painful over the life of the loan. At a 2% real yield, the monthly payment doesn't get inflated away anywhere near as quickly as it did during the 2010s, when real yields were near zero and nominal wage growth was the borrower's friend. The same nominal mortgage rate is a different deal depending on the real yield underneath it.

3. The Fed's policy stance. The federal funds rate minus expected inflation is, again roughly, the real policy rate — the proper measure of whether the Fed is being restrictive, neutral, or accommodative. With nominal policy in the high 4s and core inflation in the mid 2s, the real policy rate is somewhere around +2%. That is the highest sustained real policy rate the U.S. has run since before the financial crisis. Whether that constitutes "tight" depends on where you think the neutral real rate sits, and the honest answer is that economists disagree by a full percentage point or more — but the direction of the comparison is unambiguous, and the real yield on DFII10 is the cleanest market read on where the long-run real rate is settling.

In all three cases, the nominal number is the one that gets quoted. The real number is the one that determines the outcome.

What this does not tell you

I want to be precise about three limits, in the same spirit as last week's post on the curve.

It does not tell you what inflation will actually be. The 2.40 breakeven is the market's expectation. The market has been wrong about inflation by hundreds of basis points in both directions inside the last five years. The TIPS holder is protected from inflation surprises in a way the nominal-bond holder is not, but the breakeven spread is a forecast, and forecasts are forecasts.

It does not tell you where real yields should be. "Above the post-2010 average" or "below the pre-2008 average" describes the past distribution, not a target. The neutral real rate — call it r-star — is unobservable and contested. Anyone who tells you the current real yield is "too high" or "too low" is implicitly claiming a r-star number, and you should ask them which one and why.

And it does not tell you the path. The real yield can sit at 2% for years, or it can revert to zero in twelve months. Levels are levels. Levels are not trajectories.

How to pull this yourself

Three FRED series, same drill as last week:

• DGS10 — nominal 10-year Treasury, daily.
• DFII10 — 10-year TIPS, daily. The real yield series.
• T10YIE — pre-computed breakeven inflation, daily. Saves the subtraction.

Chart DFII10 alone, range "Max," and the regime shifts I described above are visible at a glance: the pre-2008 plateau near 2%, the long dip into negative territory through the 2010s, the sharp 2022 climb, and the current plateau in the 1.7–2.3 band. The thing worth watching from here is whether the plateau holds, drifts higher, or breaks back down — each of those scenarios implies a meaningfully different environment for everything from your mortgage to your equity weighting.

Next week the post is back to Jay on the engineering side, with a piece about the cost of running this whole pipeline — what the FRED API, the Bridge, the Supabase row, the persona prompts, and the publish script actually add up to in dollars per founder log, and where the cost is and isn't where I expected it to be.

— Ravi