Treasury bill yields rose in 2026, and the rise grew with maturity. Between December 31, 2025 and October 30, 2026 the 4-week bill's investment yield gained 0.33 point and the 52-week bill's 0.88 point, in Treasury's daily bill rates. The Fed raised its target range only once, by a quarter point in September, so most of the move came from inflation and from investors' changing view of the Fed, while bill supply climbed to a record. Below are the month-end rates, the meetings and auctions that stood out, and the supply and debt-limit picture as of November 2, 2026. The securities themselves are covered in the US Treasuries hub.
How have T-bill yields changed in 2026?
Every bill term ended October higher than it started the year, with the 52-week bill up 0.88 point and the 4-week up 0.33.
The table uses Treasury's investment yield, its coupon-equivalent column, for the most recently auctioned bill of each term on the last trading day of each month. The final column, the 52-week yield minus the 4-week, shows the slope of the bill curve: negative when investors expect rates to fall, positive when they expect them to rise or want extra pay for tying money up longer.
| Month-end | 4-week | 13-week | 26-week | 52-week | 52-week minus 4-week |
|---|---|---|---|---|---|
| Dec 31, 2025 | 3.65% | 3.65% | 3.61% | 3.48% | −0.17 |
| Jan 30 | 3.69% | 3.66% | 3.63% | 3.48% | −0.21 |
| Feb 27 | 3.69% | 3.67% | 3.62% | 3.48% | −0.21 |
| Mar 31 | 3.70% | 3.69% | 3.72% | 3.67% | −0.03 |
| Apr 30 | 3.67% | 3.67% | 3.70% | 3.72% | +0.05 |
| May 29 | 3.69% | 3.68% | 3.75% | 3.79% | +0.10 |
| Jun 30 | 3.67% | 3.83% | 3.98% | 3.97% | +0.30 |
| Jul 31 | 3.69% | 3.77% | 3.95% | 4.06% | +0.37 |
| Aug 31 | 3.75% | 3.87% | 4.02% | 4.14% | +0.39 |
| Sep 30 | 3.91% | 4.13% | 4.34% | 4.54% | +0.63 |
| Oct 30 | 3.98% | 4.08% | 4.25% | 4.36% | +0.38 |
The year falls into three phases. Through February the curve sloped down and barely moved, consistent with investors expecting the Fed's next step to be a cut. From March to August the longer bills climbed while the 4-week bill stayed between 3.67% and 3.75% at month-ends, because the Fed's range did not change but expectations about it did. In September every term jumped around the Fed's hike, and in October the long end gave part of that back. Averaged over each month, the 13-week bill went from 3.65% in January to 4.15% in October. The daily highs came on September 29 for the 52-week bill, at 4.58%, and September 28 for the 26-week, at 4.42%; the lows came in January and February, including 3.41% for the 52-week on February 10.
Worked example: What the year's rise meant for $25,000 rolled in 13-week bills
Treasury prices a 13-week bill from its auction discount rate: price = face value × (1 − rate × 91 ÷ 360).
- January 5 auction, discount rate 3.540%: $25,000 of face value cost $24,776.29 and earned $223.71 over 91 days.
- September 28 auction, discount rate 4.110%: the same face value cost $24,740.27 and earned $259.73.
- The same balance earned about $36 more per quarter, or roughly $144 a year at that pace.
The Treasury bill calculator runs the same arithmetic for any rate and term, and T-bill discount rate vs investment rate explains why the two quotes differ.
Which Fed meetings moved bill yields?
June 17 moved bills more than any other 2026 meeting, even though the Fed held rates that day.
The FOMC kept its range at 3.50% to 3.75% at the first five meetings of 2026, raised it to 3.75% to 4.00% on September 16 and held again on October 28. The table shows investment yields on the trading day before each decision and two trading days after it.
| Meeting | Decision | 13-week bill | 52-week bill |
|---|---|---|---|
| Jan 28 | Hold; two officials preferred a cut | 3.66% to 3.66% | 3.51% to 3.48% |
| Mar 18 | Hold; statement first cites developments in the Middle East | 3.69% to 3.71% | 3.62% to 3.81% |
| Apr 29 | Hold; one vote for a cut, three against an easing bias | 3.68% to 3.67% | 3.71% to 3.72% |
| Jun 17 | Hold, 12 to 0; shorter statement without the "additional adjustments" language | 3.72% to 3.79% | 3.84% to 4.03% |
| Jul 29 | Hold; three officials preferred a hike | 3.86% to 3.77% | 4.08% to 4.06% |
| Sep 16 | Hike to 3.75% to 4.00%, 12 to 0 | 4.07% to 4.08% | 4.36% to 4.41% |
| Oct 28 | Hold; two officials preferred a hike | 4.15% to 4.08% | 4.51% to 4.36% |
June shows how bills react to expectations rather than actions. The June projections lifted the median official's year-end rate from 3.4% in March to 3.8%, with 9 of the 18 officials now projecting at least one hike, and the statement dropped its language about "additional adjustments" to the range. The 52-week bill rose 0.14 point that day, its largest one-day gain of the year. July ran the other way: three officials dissented in favor of a hike, but the 13-week bill fell 0.07 point on the day of the hold, its largest daily drop of 2026, which suggests some investors had expected an increase. By the time the Fed did raise rates in September, the 13-week bill moved 0.01 point across the meeting. The October Fed decision post covers the latest meeting term by term, and how Fed rate decisions affect T-bill rates explains the mechanics.
Inflation explains the turn. The consumer price index rose 2.4% over the 12 months to January and to February, then 3.3% to March, 3.8% to April and 4.2% to May, before easing to 3.4% in July and August and rising to 3.7% in September. The April statement said inflation was elevated "in part reflecting the recent increase in global energy prices". In April and May the 13-week bill's month-end yield was below the 12-month inflation rate, so bill holders lost purchasing power before tax; the T-bill yields vs inflation study tracks that gap back to 2000.
Which 2026 bill auctions stood out?
The year's auction lows came in January and February and its highs at the end of September, at the largest 13-, 26- and 52-week sizes of the year.
Results come from Treasury's Fiscal Data and TreasuryDirect records. The investment rate is the bill's yield on a 365-day basis at the highest accepted bid, and the bid-to-cover ratio is the amount bid divided by the amount sold; how Treasury auctions work explains both.
| Auction date | Bill and size | Result | Why it stands out |
|---|---|---|---|
| Jan 5 | 13-week, $86 billion | 3.622% investment rate | Lowest 13-week rate of 2026, at the year's smallest 13-week size |
| Jan 5 | 26-week, $77 billion | 3.586% | Lowest 26-week rate of 2026 |
| Feb 17 | 52-week, $50 billion | 3.480%; bid-to-cover 2.96 | Lowest 52-week rate and weakest 52-week demand ratio of the year |
| May 21 | 27-day cash management bill, $25 billion | 3.665%; bid-to-cover 4.60 | The only cash management bill of 2026 through October, maturing June 18, after the June 15 tax date |
| June 11 to 25 | 4-week, $70 billion each week | Smallest 4-week size of 2026 | Treasury cut short bill sizes around the mid-June tax date |
| Sept 28 | 13-week, $95 billion, and 26-week, $82 billion | 4.211% and 4.441% | Highest 2026 rates for both terms |
| Sept 29 | 52-week, $54 billion | 4.616%; bid-to-cover 3.07 | Highest bill auction rate of 2026 |
October brought the year's largest 4- and 8-week auctions, as Treasury had signaled in August, while rates eased after the Fed's October 28 hold. The most recent results are in the table below, which updates as Treasury publishes them.
| Auction date | Bill | High discount rate | Investment rate | Bid-to-cover | Offering size |
|---|---|---|---|---|---|
| Oct 15, 2026 | 8-Week bill | 4.050% | 4.132% | 2.26 | $105B |
| Oct 15, 2026 | 4-Week bill | 4.000% | 4.068% | 2.56 | $110B |
| Oct 14, 2026 | 17-Week bill | 4.195% | 4.313% | 2.79 | $75B |
| Oct 13, 2026 | 6-Week bill | 3.980% | 4.055% | 2.58 | $95B |
| Oct 13, 2026 | 26-Week bill | 4.200% | 4.351% | 2.76 | $82B |
| Oct 13, 2026 | 13-Week bill | 4.085% | 4.185% | 2.68 | $95B |
| Oct 8, 2026 | 4-Week bill | 3.980% | 4.048% | 2.40 | $110B |
| Oct 8, 2026 | 8-Week bill | 3.980% | 4.060% | 2.77 | $105B |
How did bill supply change in 2026?
Bills outstanding reached a record $7.25 trillion at the end of August, as Treasury held note and bond auction sizes steady and let bills absorb its borrowing.
| Month-end | Bills outstanding | Share of marketable debt |
|---|---|---|
| Dec 31, 2025 | $6.55 trillion | 21.6% |
| Mar 31 | $6.82 trillion | 22.1% |
| Apr 30 | $6.62 trillion | 21.6% |
| Jun 30 | $6.69 trillion | 21.5% |
| Aug 31 | $7.25 trillion | 22.8% |
| Sep 30 | $7.12 trillion | 22.4% |
The figures come from the Monthly Statement of the Public Debt. The April dip is the usual tax-season pattern, with individual tax payments letting Treasury shrink bill supply by about $200 billion that month, and July and August added about $560 billion in two months. Over the first nine months, bills outstanding rose about $570 billion.
Treasury's August 5 refunding statement said it expected to keep note, bond and floating rate note auction sizes unchanged "for at least the next several quarters" and that it was monitoring "growing demand for Treasury bills from the private sector". It raised regular bill sizes in steps instead: the 13-week from $86 billion in January to $95 billion by late September, the 26-week from $77 billion to $82 billion and the 52-week from $50 billion to $54 billion.
Demand from the Fed faded over the same months. The New York Fed's reserve management purchases of bills and other short-dated Treasuries ran at about $40 billion a month from mid-December 2025 to mid-April, then $25 billion, then $10 billion a month until mid-August, and none since. It still reinvests principal from its agency securities into bills, about $15 billion to $17 billion a month since mid-August.
Is a debt-limit deadline coming?
Not this year: the limit has been $41.1 trillion since July 2025, and Treasury still had room under it at the end of October.
On October 29, 2026, debt subject to the limit was about $40.39 trillion in the Daily Treasury Statement, against a statutory limit of $41.10 trillion, leaving roughly $0.71 trillion of room. Total public debt was $40.59 trillion that day, up $2.08 trillion since December 31, 2025, in Treasury's Debt to the Penny data. Outside projections cited by the Congressional Research Service had debt reaching the limit in early to mid-2027, after which extraordinary measures could postpone a binding limit by several months. Standoffs matter for bills because those maturing near a feared payment date can trade at sharply higher yields, as are Treasuries risk-free? describes for 2023.
What is scheduled for the rest of 2026?
Three events on the calendar bear directly on bills before year-end: Treasury's refunding, the October inflation report and the Fed's December meeting.
Treasury releases its next quarterly refunding statement, with updated guidance on bill and coupon sizes, on November 4. The Bureau of Labor Statistics publishes October CPI on November 10, and the FOMC announces its final decision of the year at 2:00 p.m. Eastern on December 9, with new projections. Daily yields by term are on T-bill rates today.
What are the risks of reading this year's yields as a trend?
Bill yields rest on expectations that can reverse quickly, so the main risks are assuming the rise continues, locking in near a peak and overlooking inflation.
- Past moves do not predict future ones. Yields climbed this year because inflation and the Fed's outlook changed; if either shifts again, bill rates can fall as fast as they rose.
- Reinvestment. A bill fixes its rate only until it matures. Short bills roll into whatever rates prevail, so the rollover gain in the example above works in reverse when rates fall; a T-bill ladder spreads that timing.
- Price before maturity. A 52-week bill sold after yields rise can fetch less than its purchase price, as selling Treasuries before maturity explains; held to maturity it pays face value.
- Inflation. In April and May bill yields trailed the 12-month inflation rate, so the real return depends on prices as much as on the rate.
- Taxes. Bill interest is federally taxable but exempt from state and local income tax, which are T-bills taxable? covers.
- Credit. Treasury bills are backed by the full faith and credit of the US government, and debt-limit standoffs have been the main credit-related disruption to bill pricing in recent years.