How fast does the auction panel update after results?
Seconds. Helious picks up the Treasury results as they cross the tape and scores the tail, cover and bidder split straight away. You do not have to wait for a wire desk to write a recap.
Auction Analysis: Reading the Tail, Stop-Through, Verdict and Bidder Split
The auction panel scores every US Treasury auction the moment results cross the tape, so you are not waiting on a wire desk to write it up. A rates trader reads the tail, or stop-through, in basis points, then the bid-to-cover against its own trailing average, then how the award split between indirect, direct and dealer bidders. On top of those three sits a one-word verdict. The how to read a Treasury auction guide walks through a live worked example step by step.
The tail, or stop-through
The auction tail is the number to look at first. Take the auction's high yield, the stop-out, and subtract the when-issued yield that was trading in the seconds before the bid deadline. Helious measures against the real when-issued level rather than a reconstructed proxy, so the number means what it says.
A positive tail means the auction had to concede yield to clear. That is a soft result. A negative number is a stop-through: demand cleared richer than the screen, which is a strong one. Both print in basis points, so a 1.8bp tail and a 0.6bp stop-through are directly comparable.
Coupons tail. Bills do not. They are quoted on a discount-rate basis while when-issued trades on an investment-rate basis, so subtracting one from the other is not like for like. On the front end, read the cover and the bidder mix instead.
Bid-to-cover and the 12-month average
Bid-to-cover is total bids divided by the amount sold, so it tells you how deep the demand was. The raw number does not travel across tenors, though. A 2.35 cover is soft for a 10-year note and strong for a 30-year bond, which is why the panel always prints it beside that tenor's own 12-month average. Read it over a run of auctions rather than one at a time. A cover that keeps slipping under its average is the usual sign that demand is fading.
Who actually bought
Indirect, direct and primary-dealer takedown add up to 100% of the competitive award between them. Indirects are mostly foreign central banks and real money bidding through dealers. So a high indirect share with a low dealer take means end investors absorbed the supply. When the dealer take swells instead, the street was left holding what investors did not want. The split often tells you more than the tail does, and it is most worth reading when the two disagree.
The verdict
Helious rolls the tail, the cover against its average and the bidder split into one verdict, either STRONG, IN LINE or WEAK. Read that first and open the individual fields only when the result matters. A stop-through with an above-average cover and heavy indirects prints STRONG, which is supportive for the curve. A tail with a soft cover and a fat dealer take prints WEAK, a concession that can lift yields. Past results by tenor live on the auction hubs. The running numbers are in the tail dataset, and the next auction is scored live on the [desk](/).
FAQ
Is the when-issued tail real or reconstructed?
Real. Helious measures the tail against the when-issued yield trading just before the bid deadline, not a proxy backed out of other prints, so you can trust a small coupon tail or stop-through.
Why does a bill auction show no tail?
Bills are quoted on a discount-rate basis and the when-issued market trades on an investment-rate basis, so subtracting one from the other is not a like-for-like tail. Read a bill on its bid-to-cover and on the split between indirect, direct and dealer bidders instead.
Where can I see an auction's history over time?
Every tenor has its own hub, such as the 10-year note. The full running series is in the Treasury auction tails dataset.