Glossary term
What is a Treasury auction tail?
On , at the auction of the 30-year bond (a reopening), the high yield was 5.1 basis points above the median yield and 1.8 basis points above the same day's par curve. 500metrics shows no tail.
High minus median at the 30-year bond auction of 8 October 2026: 5.1 bp, below the median of the earlier auctions shown, 5.8 bp
The linesLatest:
- High minus median5.1 bp
- High minus the par curve1.8 bp
Each point is one 30-year bond auction; pointing at the chart shows its date and figures.
The linesLatest:
- High minus median5.1 bp
- High minus the par curve1.8 bp
Inspect and compare dates
| Auction date | High minus median | High minus the par curve |
|---|---|---|
| 5.1 basis points | 1.8 basis points | |
| 5.8 basis points | −6.2 basis points | |
| 6.6 basis points | 0.6 basis points | |
| 5.1 basis points | 0.8 basis points | |
| 6.0 basis points | 7.0 basis points | |
| 5.6 basis points | 1.6 basis points | |
| 5.3 basis points | −2.4 basis points | |
| 4.6 basis points | −0.9 basis points | |
| 3.2 basis points | 3.0 basis points | |
| 4.5 basis points | −0.5 basis points |
Show 14 more rows
| Auction date | High minus median | High minus the par curve |
|---|---|---|
| 5.3 basis points | −1.7 basis points | |
| 6.4 basis points | −0.6 basis points | |
| 6.4 basis points | 1.4 basis points | |
| 6.6 basis points | 0.1 basis points | |
| 7.3 basis points | 0.3 basis points | |
| 5.1 basis points | 2.9 basis points | |
| 4.4 basis points | 0.4 basis points | |
| 7.0 basis points | −1.1 basis points | |
| 8.3 basis points | −4.7 basis points | |
| 6.3 basis points | 3.3 basis points | |
| 6.8 basis points | 2.8 basis points | |
| 4.3 basis points | 0.3 basis points | |
| 6.0 basis points | −1.5 basis points | |
| 4.3 basis points | 0.8 basis points |
Right now
High minus median: 5.1 basis points at the 30-year bond auction of , a reopening.
- High yield 5.618%
- Median yield 5.567%
- Par curve, nominal, 30-year 5.60%
Across auctions
5.1 bp is below the median of the 23 earlier 30-year bond auctions shown, 5.8 bp.
Of the 24 auctions shown, the highest was 8.3 bp on , the lowest 3.2 bp on .
Understanding the Treasury auction tail
Where it stands today
High minus median: 5.1 basis points at the 30-year bond auction of .
What does the term mean?
The tail of a Treasury auction is the high yield minus the when-issued yield just before bidding closed. An auction "tails" when Treasury has to accept a higher yield than the market was trading at, and "stops through" when it accepts a lower one.
Read more
Why 500metrics does not publish a tail
The when-issued yield is a market quote from trading platforms, not an official number. Treasury does not publish it, and the sites that show a tail take it from their own licensed feed. 500metrics shows only official figures, so it shows no tail and never calls another number one.
The two official stand-ins
Both come from Treasury's own numbers, and every note, bond and TIPS auction page shows them:
- High minus median. The high yield minus the median yield, in basis points: how far the cut-off sat above the middle of the winning bids. Both are in the auction results.
- High minus the par curve. The high yield minus the same day's Treasury par yield curve rate at the nearest maturity, in basis points. Treasury sets the curve from market quotes later that afternoon, so it is the closest official picture of where the market traded that day. TIPS are compared with the real curve.
What these stand-ins cannot tell you
- The exact market yield at the moment bidding closed. The par curve is set at the end of the day, for a standard maturity, not for the security sold.
- A tail as other sites report it. Their figures and these will differ, sometimes in sign.
Drafted with AI assistance from official sources; checked against the sources listed below.
The numbers behind the chart
What were the figures at the latest auction?30-year bond (reopening), 8 October 2026
| Figure | Value |
|---|---|
| High minus median | 5.1 basis points |
| High yield | 5.618% |
| Median yield | 5.567% |
| Par curve, nominal, 30-year | 5.60% |
| High minus the par curve | 1.8 basis points |
Which pages show these figures?
Page updated