Why Treasury Yields Rose After the Fed's September Rate Hike

The 30-year Treasury yield closed at 5.56% on 13 October, 11 basis points below the 5.67% it reached on 7 October and higher than the 5.35% it closed at on the day the Federal Reserve raised interest rates a month earlier. The 10-year closed the same day at 5.21%, up from 4.83% on 9 September. A rate increase is supposed to make borrowing more expensive at the short end and leave the long end to the market's own judgment about growth and inflation. Through October, both ends moved the same direction.

We flagged this exact gap in September: Washington sets the policy rate, not the price of a 30-year bond, and a government that shortens the average maturity of its own debt to dodge that price can only dodge it for a while. The Federal Reserve's 16 September decision is the test the earlier piece did not yet have on the record. The Federal Open Market Committee raised the federal funds rate by a quarter point, to a target range of 3.75% to 4.00%, in a unanimous 12-0 vote. The statement said inflation was still running too hot and described the move as support for a timelier return to the Committee's 2% goal. A month later, the part of the curve the Fed does not directly set is pricing in more of that same inflation risk, not less.

What moved, and what didn't

Short rates did what a hike does. They went up on schedule with the policy decision. Long rates did something else. Between 9 September and 13 October the 10-year added 38 basis points and the 30-year added 28. Measured from the day of the hike, 16 September, they added 20 and 21. Most of that came after a hike the Fed itself framed as disinflationary, which is usually the condition under which long yields fall, not climb.

The distinction matters because the two ends of the curve answer different questions. The federal funds rate is a lever the Fed sets directly, to make short-term credit cheaper or dearer. The 10- and 30-year yields are a price the market sets for itself, built from its own expectations for inflation, growth and how much new debt the Treasury will need to sell. A hike can succeed at the first job and still fail at the second, if the market reads the move, or the deficit behind it, as reason to demand more compensation for lending long rather than less.

The buyer changed sides, for one month

The Treasury's international capital data for July, released on 16 September, the same day as the Fed decision, showed foreign official institutions, mainly central banks, net buying $44.4 billion of long-term US securities. Private foreign investors net sold $3.7 billion. Total net foreign buying for the month came to $40.6 billion.

That is the mirror image of what we reported in September. In June, private investors bought $169.8 billion while official institutions bought a smaller $37.3 billion. In March, private investors bought $111.4 billion while official institutions were net sellers of $14.9 billion. Through the spring and early summer, private money carried the market and official money was the swing factor. In July, official money carried it and private money stepped back. One month of custodial data, revised for months afterward, is not a new trend. It is a data point that cuts against the one we highlighted six weeks ago, and it belongs in the record alongside it rather than in place of it.

The bill came due before the year did

Net interest on the federal debt reached $1.017 trillion for fiscal year 2026 through the end of August, the Treasury's Monthly Treasury Statement shows, with $86 billion of that in August alone. The Congressional Budget Office had estimated $1.04 trillion of interest for the entire fiscal year when it published its forecast in September. The actual number got there, or close to it, with a full month still to be counted.

The wider number

The Congressional Budget Office's Monthly Budget Review for September, published 8 October once the fiscal year had closed, put the full FY2026 deficit at $2.0 trillion on $7.4 trillion of outlays against $5.4 trillion of revenue. That is $218 billion wider than fiscal year 2025. Revenue rose 3%, driven by individual income and payroll tax collections. Outlays rose 6%, roughly double the pace, pulled up by net interest, the major benefit programs, defense and education. The deficit widened because spending outran the tax take, not because the tax take fell.

Where it shows up for a borrower who has never bought a bond

Freddie Mac's weekly survey put the average 30-year fixed mortgage rate at 7.40% on 8 October, up from 7.28% the week before and from 6.30% a year earlier. Mortgage pricing tracks the 10-year Treasury yield more closely than it tracks the Fed's policy rate, because a 30-year mortgage is, in effect, a long-duration bond with prepayment risk attached. Over the twelve months in which the Fed held, then raised, its policy rate once, the average mortgage quote rose by roughly a full percentage point.

This is the version of "the price of long credit" that doesn't require a chart to notice. The government's own financing cost and a household's mortgage quote are set by the same part of the curve, and neither the Fed's hike nor the Treasury's buyback program has moved that part of the curve down yet.

What we're watching

The Treasury's next TIC release, covering August, is due 16 October. It will show whether July's official-led buying held or whether private investors came back in. One more month of official-led flow would start to look like a pattern rather than noise; a reversion to private-led buying would say July was the outlier. Either way, the series is the cleanest monthly read we have on who is actually absorbing the debt the Treasury is selling, and it is worth checking against the yield move rather than taken as a story on its own.

The FOMC meets again on 27 and 28 October, its first chance to confirm or walk back the view that inflation needs another dose of tightening; nothing about that outcome is known yet. China's transitional window for declaring historic offshore-trust liabilities under its new 20% tax closes 22 October, with three years of retroactive cover attached, as we reported in September.

The next test is 4 November, when the Treasury's enlarged buyback authority in the 10-to-30-year sector, which it doubled from $2 billion to at least $4 billion per operation in September, is due to expire or be renewed. A renewal at the larger size would be the clearest signal yet that Washington expects to keep leaning on its own balance sheet to manage the long end, rather than relying on the hike to do that work for it.

Take the case against alarm first. A single month of Treasury data is noisy, custodial reporting lags actual ownership by weeks, and July is a thin month for the kind of flows that move the headline number. Revenue also grew in fiscal 2026, up 3% on the Congressional Budget Office's count, so the interest bill is not rising against a flat base. Thirty-year paper at 5.56% is also the best nominal compensation for lending to the US government in close to two decades, and for a buyer with a matching long liability, a pension fund most of all, that is a real trade rather than a warning sign.

Our reading stays close to what we wrote in September. The Fed delivered the hike it said inflation required, and the part of the market that prices the government's own long-term borrowing cost did not reward it. That is the data point that matters more than any single month's buyer mix. A hike that does not bring long yields down is a hike that has not yet done its job, and the Treasury's own financing calendar, the buyback authority due at the start of November, says more about which way this goes than the next speech will.

Why did Treasury yields rise after the Federal Reserve raised interest rates?

The Fed's 16 September increase set the federal funds rate, which anchors short-term borrowing costs. It does not set the price of long-dated government bonds, which investors price against their own view of inflation, deficits and future Fed policy. Between 9 September and 13 October the 10-year Treasury yield rose from 4.83% to 5.21% and the 30-year from 5.28% to 5.56%, the opposite of the usual pattern after a hike aimed at slowing inflation.

What did the Federal Reserve decide on 16 September 2026?

The Federal Open Market Committee raised the federal funds rate by 25 basis points, to a target range of 3.75% to 4.00%, in a unanimous 12-0 vote. The statement said inflation was still running too hot and described the increase as support for a timelier return to the Committee's 2% goal.

Are foreign central banks still buying US Treasuries in 2026?

It varies by month. US Treasury data for July 2026 show foreign official institutions, mainly central banks, net buying $44.4 billion of long-term US securities, while private foreign investors net sold $3.7 billion. That is the reverse of March and June, when private investors bought and official institutions were flat to selling. One month is not enough to call a new pattern.

How much does the US government spend on interest now?

Net interest on the federal debt totaled $1.017 trillion for fiscal year 2026 through the end of August, the Treasury's Monthly Treasury Statement shows, including $86 billion in August alone. That is close to the $1.04 trillion the Congressional Budget Office estimated for the entire fiscal year when it published its forecast in September.

What was the US federal budget deficit for fiscal year 2026?

The Congressional Budget Office put the completed fiscal year 2026 deficit, which ended 30 September, at $2.0 trillion on $7.4 trillion of outlays against $5.4 trillion of revenue. That is $218 billion wider than fiscal year 2025, with outlays rising 6% against 3% revenue growth.