How Treasury Auctions Work: Bid-to-Cover and Tails

The US Treasury borrows by auctioning bills, notes and bonds: it announces the amount, investors bid the yield they will accept, and Treasury fills the lowest-yield bids first until the offering is sold, with every winner receiving the same yield, the "high yield" of the last bid accepted ^[1]^[2]. In the 10-year note auction of October 7, 2026, Treasury sold $39 billion at a high yield of 5.300%, and bids totaled 2.77 times the amount sold, the bid-to-cover ratio ^[4]. A "tail" is the gap when the high yield ends up above the yield at which the new note was trading just before the auction, a sign of softer demand.

How does a Treasury auction work, step by step?

TreasuryDirect describes four steps: Treasury announces the auction, bidders submit bids, the auction is held, and the securities are issued ^[1]. The announcement gives the security, the amount offered and the key dates. For the reopened 10-year note sold on October 7, 2026, the announcement came on October 1, bids closed at 12:00 p.m. Eastern Time for noncompetitive bids and 1:00 p.m. for competitive bids, and the notes were issued on October 15 ^[6].

Competitive and noncompetitive bids

Noncompetitive bids accept whatever yield the auction produces and are filled in full, up to $10 million per bidder per auction. Individuals buying through a TreasuryDirect account must bid this way ^[1].
Competitive bids state the yield the bidder will accept. No single bidder can be awarded more than 35% of the offering amount, and competitive bids go through a bank, broker or dealer, or directly for eligible institutions ^[1].

How the high yield is set

Treasury first accepts all valid noncompetitive bids, then accepts competitive bids from the lowest yield upward until the full amount is sold ^[1]. The yield of the last accepted bid is the high yield, also called the stop-out yield. Bids exactly at the stop-out are prorated, and everyone who wins pays the same price; Treasury has used this single-price (uniform-price) method for all marketable securities since November 1998 ^[2].

In the October 7 auction, the lowest accepted bid was 4.300%, half of the accepted competitive amount was bid at or below 5.255% (the median), and the high yield was 5.300% ^[4]. Bids at 5.300% received 57.60% of the amount they asked for ^[4]. Because the yield was above the note's 4-5/8% coupon, the note sold at a discount, at a price of 94.864261 per 100 of face value ^[4].

What is the bid-to-cover ratio?

The bid-to-cover ratio is the amount bid divided by the amount sold to the public. Treasury's results release shows the arithmetic: on October 7, 2026, $108.07 billion was tendered for $39.00 billion accepted, a ratio of 2.77 ^[4]. The Federal Reserve's purchases for its own account (SOMA, the System Open Market Account) are added on top of the offering and left out of the ratio; they were $926 million on October 7 and $10.6 billion on August 12, as the Fed rolled over maturing Treasury securities it held ^[4]^[5].

A higher ratio means more demand, but it is most useful compared with recent auctions of the same maturity:

Auction date (10-year note)	Amount offered	High yield	Bid-to-cover	Indirect bidders	Direct bidders	Primary dealers
June 10, 2026 (reopening)	$39 billion	4.538%	2.57	78.2%	12.3%	9.5%
July 8, 2026 (reopening)	$39 billion	4.580%	2.59	81.5%	10.7%	7.8%
August 12, 2026 (new issue)	$42 billion	4.683%	2.53	76.7%	14.7%	8.6%
September 9, 2026 (reopening)	$39 billion	4.834%	2.71	79.2%	16.5%	4.3%
October 7, 2026 (reopening)	$39 billion	5.300%	2.77	80.3%	17.1%	2.5%

Source: Treasury auction results via TreasuryDirect ^[4]^[5]^[6]. Bidder shares are percentages of accepted competitive bids.

The high yield rose 62 basis points between the August 12 and October 7 auctions, in line with the market: Treasury's 10-year par yield was 5.28% on October 7, 2026 ^[10]. A basis point is one hundredth of a percentage point.

Who buys at Treasury auctions?

Treasury's results group competitive awards into three kinds of bidders ^[3]:

Primary dealers are banks and broker-dealers that trade with the New York Fed and are expected to bid in every Treasury auction at reasonably competitive prices ^[7]. The 26 dealers include J.P. Morgan Securities, the broker-dealer of JPMorgan Chase (JPM); Goldman Sachs & Co., part of Goldman Sachs (GS); Morgan Stanley & Co. (MS); BofA Securities, part of Bank of America (BAC); and Wells Fargo Securities (WFC) ^[7]. In the results, "primary dealer" means dealers bidding for their own account ^[3].
Direct bidders are other firms bidding for their own account without going through a dealer ^[3].
Indirect bidders are customers placing competitive bids through a primary dealer or a direct submitter ^[3]. Treasury notes that the categories do not indicate where a bidder is based ^[3].

Because dealers must bid, they take whatever others do not, so a low dealer share signals strong outside demand. On October 7, primary dealers bid for $52.88 billion but were awarded only $984 million, 2.5% of the competitive amount, while indirect bidders took 80.3% ^[4].

What is a tail in a Treasury auction?

A new Treasury security starts trading before it exists. When-issued (WI) trading is trading of the new security after the auction is announced but before it is issued, and the New York Fed notes that it promotes price discovery, which may reduce uncertainty at auction ^[8]. The when-issued yield just before the 1:00 p.m. bid deadline is the market's estimate of where the auction will clear.

Traders compare the high yield with that when-issued yield:

Tail: the high yield is above the when-issued yield. For example, if the note trades at 5.000% when-issued and the auction clears at 5.012%, it "tailed" by 1.2 basis points: Treasury had to pay more than the market expected, a sign of weaker demand.
Stop-through: the high yield is below the when-issued yield, a sign of stronger demand.
On the screws: the two are equal.

Treasury's results do not report the when-issued yield, so tails are measured from market quotes and can differ slightly by data source. The bid-to-cover ratio and bidder shares, by contrast, come straight from Treasury ^[4].

A Treasury auction sells to the lowest-yield bids first, gives every winner the same yield, and is judged by its bid-to-cover ratio, the share taken by dealers and whether it tails the when-issued yield.

What is the quarterly refunding?

Once a quarter, in February, May, August and November, Treasury sells 3-year notes and new 10-year notes and 30-year bonds in a single week, called the refunding, after publishing a statement on its borrowing plans the week before ^[6]^[9]. The August 5, 2026 statement offered $125 billion: $58 billion of 3-year notes on August 11, $42 billion of 10-year notes on August 12 and $25 billion of 30-year bonds on August 13, all issued on August 17 ^[9]. That refunded about $96.3 billion of maturing notes and bonds held by private investors and raised about $28.7 billion of new cash ^[9].

The statement also said Treasury expected to keep nominal coupon and floating-rate note auction sizes unchanged "for at least the next several quarters," and set the next refunding statement for November 4, 2026 ^[9]. Between refundings, the 10-year note is reopened: more of the same note, with the same coupon and maturity, is sold in the following two months, which is why the September and October 2026 auctions were for "9-year 11-month" and "9-year 10-month" notes maturing on August 15, 2036 ^[6].

Key takeaways

Treasury fills the lowest-yield bids first and gives every winner the high yield; the October 7, 2026 10-year auction cleared at 5.300% ^[2]^[4].
Noncompetitive bids, up to $10 million, are filled in full; no competitive bidder can win more than 35% of an auction ^[1].
Bid-to-cover was 2.77 on October 7, 2026, up from 2.53 at the August 12 new issue ^[4]^[5].
Indirect bidders took 80.3% of the October 7 auction and primary dealers 2.5%, the lowest dealer share of the five auctions from June to October 2026 ^[4]^[6].
The August 2026 refunding sold $125 billion of 3-, 10- and 30-year securities and raised about $28.7 billion of new cash ^[9].

Frequently asked questions

What is a good bid-to-cover ratio for a Treasury auction?

There is no fixed threshold; analysts compare it with recent auctions of the same security. For 10-year notes from June to October 2026, it ranged from 2.53 to 2.77 ^[6].

Can individuals buy at Treasury auctions?

Yes. Individuals can place noncompetitive bids through TreasuryDirect or a broker, from $100 up to $10 million per auction, and receive the auction's yield ^[1]^[2].

What does it mean when a Treasury auction tails?

The auction's high yield came in above the when-issued yield trading just before the 1:00 p.m. deadline, meaning Treasury paid more than the market expected. A tail of 1 basis point is a 0.01 percentage point miss.

Who are indirect bidders in Treasury auctions?

Customers who place competitive bids through a primary dealer or another direct submitter rather than bidding for their own account. They took 80.3% of the October 7, 2026 10-year auction ^[3]^[4].