Treasury Auctions: 2 Bid Types and What You Get

Maya has $10,000 sitting in a checking account earning nothing. A 4-week Treasury bill auction is open, and the Treasury wants to sell $25 billion of them. She can bid in, but there are two ways to do it, and the difference between those two ways is whether she gets her $10,000 or gets nothing back. Here is how both paths work, what price she actually pays, and why the “safer” option is also the one that gives her zero control over the rate.

Key points

• A noncompetitive bid guarantees you an allocation at the stop-out price; a competitive bid can fail if your quoted rate is too low.
• In a single-price auction, every accepted bidder pays the same stop-out price, regardless of what rate they originally bid.
• For a 4-week T-bill with a 4.25% stop-out discount rate, a $10,000 face position costs $9,966.94 and returns $33.06 at maturity.
• Settlement now happens in T+1 for most U.S. securities, meaning your funds move the business day after the auction, not two days later.
• The maximum noncompetitive bid for an individual is $1 million in face value per auction; competitive bids have no individual cap but must meet a $100 minimum.

What actually happens at the auction window?

The Treasury opens a bid window, usually 9:00 a.m. to 1:00 p.m. Eastern. During those four hours, primary dealers, money-market funds, banks, and (if you want) individuals like Maya submit bids. Each bid says two things: a face amount and a discount rate. For T-bills, the “price” is expressed as a discount off face, not a dollar price. A 4.25% discount on a $10,000 bill means you pay $10,000 minus 4.25% of 28 days’ worth of that face.

At 1:00 p.m., the window closes. The Treasury sorts all competitive bids from highest implied price to lowest. It starts accepting from the top and works down until it has sold the target $25 billion. The last rate it accepts is the stop-out rate. In a single-price auction, every accepted bidder pays that stop-out price. You do not pay your own bid. You pay the marginal rate.

This is the single most important mechanic to internalize. Your bid is a threshold, not a price.

How does a competitive bid work for Maya?

Maya decides to bid competitively. She looks at recent 4-week auction results, sees the stop-out hovering around 4.20% to 4.30%, and decides to bid a discount rate of 4.30% for $10,000 face.

Her implied price: $10,000 × (1 − 0.0430 × 28/360) = $10,000 × 0.996656 = $9,966.56.

The auction clears. The stop-out rate comes in at 4.25%. The high yield (the highest discount rate accepted, which is the same as the stop-out in a single-price auction) is 4.30%. Maya’s bid sits exactly at the high end. She is accepted.

But she does not pay $9,966.56. She pays the stop-out price: $10,000 × (1 − 0.0425 × 28/360) = $10,000 × 0.996694 = $9,966.94.

She paid $0.38 more than her own bid implied. In a single-price auction, that is the trade. You bid a rate to qualify; you pay the market rate to settle.

Now the failure case. Suppose Maya had bid 4.40% instead. Her implied price would be $10,000 × (1 − 0.0440 × 28/360) = $9,965.78. That is below the stop-out price of $9,966.94. The Treasury would not accept her bid. She gets zero. No partial fill. No “close enough.” Her $10,000 stays in checking, and the auction result is published without her name on it.

That is the entire risk of bidding competitively: you can miss.

How does a noncompetitive bid change Maya’s outcome?

Maya’s friend Derek takes the other path. He submits a noncompetitive bid: “$10,000 face, 4-week T-bill, I accept whatever the stop-out is.” No rate. No threshold. Just a request for an allocation.

The Treasury guarantees him that allocation. He pays the stop-out price of $9,966.94. He gets $10,000 at maturity 28 days later. His profit: $33.06.

Identical economics to Maya’s winning competitive bid. The only difference is that Derek could not have lost. He also could not have “gotten a better rate than the stop-out,” because in a single-price auction, nobody does.

The practical trade: noncompetitive removes the risk of rejection and removes the need to guess the clearing rate. In exchange, you surrender any (theoretical) ability to influence the outcome. For a retail investor parking $10,000, that trade is almost always in favor of noncompetitive.

What do the two bids look side by side?

Both columns use the same dollar unit. The numbers are arithmetically consistent: $10,000 − $9,966.94 = $33.06. The discount formula is Price = Face × (1 − d × t/360), with d = 0.0425 and t = 28.

When does the money actually move?

The auction clears at 1:00 p.m. Eastern. The accepted bidders see their results at roughly 4:00 p.m. same day. But the cash does not leave Maya’s or Derek’s accounts that evening.

U.S. equity and Treasury settlement moved to T+1 in May 2024. The SEC’s final rule shortening the settlement cycle to T+1 eliminated the old T+2 standard, meaning the buyer’s funds and the seller’s securities exchange on the next business day after the trade date. For auction-settled Treasuries, the practical effect is the same: Maya’s $9,966.94 debits from her account the business day after the auction, and the bill shows up in her account that same day.

If the auction falls on a Friday, settlement is Monday. If it falls the day before a federal holiday, settlement shifts to the next open business day. The Federal Reserve’s H.15 release tracks the daily yield curve, including the 4-week T-bill rate, so you can see where the market is pricing short-term money on any given day. That number is a useful anchor before you decide what rate to bid competitively, if you choose that path.

What this does not tell you

This article walks through the auction mechanics for a single 4-week T-bill. It does not cover:

• Notes and bonds. Those auction at a price (not a discount) and a yield, and the bid structure adds a coupon dimension. The single-price logic is the same, but the arithmetic is different.
• Resale and secondary market. Once Maya holds the bill, she can sell it before maturity. The price she gets then depends on where short-term rates have moved, and that is a separate market with its own bid-ask spread.
• Tax treatment. T-bill interest is exempt from state and local income tax but fully subject to federal tax. The $33.06 profit is taxable income in the year it accrues, regardless of when Maya actually receives the cash.
• Auction mechanics for primary dealers vs. the public. Primary dealers have a minimum obligation to bid; the public does not. The auction is not a level playing field in that structural sense, even though the clearing price is the same for everyone.
• What happens in a failed or undersubscribed auction. In practice, T-bill auctions are massively oversubscribed. But if demand were thin, the Treasury could raise the stop-out rate above the high competitive bid, and some competitive bidders near the margin would be rejected.

FAQ

Can I lose money on a noncompetitive T-bill bid?

Not at the auction itself. You are guaranteed an allocation at the stop-out price, and the stop-out is always below face value (that is what a discount means). Your “return” is the difference between face and price, paid over the holding period. The only way to lose is if you sell the bill in the secondary market before maturity at a price lower than you paid, which depends on interest-rate movement, not the auction.

What is the minimum I can bid?

The minimum face amount for both competitive and noncompetitive T-bill bids is $100. You can bid in $100 increments. There is no maximum for competitive bids. For noncompetitive bids, the cap is $1 million in face value per auction for an individual.

Do I need a brokerage account to bid?

You can bid through TreasuryDirect, the Treasury’s own platform, or through a broker. TreasuryDirect lets you submit noncompetitive bids directly and also supports competitive bids. A broker will route your bid through a primary dealer. The clearing price is identical either way; the difference is convenience and whether your broker charges a fee (most do not for Treasury auctions, but some do).

What is the difference between the stop-out rate and the high yield?

In a single-price auction, they are the same number. The “high yield” is the highest discount rate (lowest price) that was accepted. The “stop-out” is the price at which the auction stopped. Because everyone pays the stop-out, the high yield and the stop-out rate are one and the same. In a multiple-price (Dutch) auction, they would differ, but the Treasury has used single-price auctions for T-bills since the 1990s.

Can I bid competitively and noncompetitive in the same auction?

Yes. You can submit both a competitive bid and a noncompetitive bid in the same auction. They are treated as separate orders. If your competitive bid is accepted, you pay the stop-out. If it is rejected, your noncompetitive bid still fills at the stop-out. There is no interaction between the two.

What happens if I bid competitively and the auction is cancelled?

Cancelled auctions are extremely rare. If one happens, no bids are accepted, no settlement occurs, and any funds that were held in escrow are released back to the bidder. You do not owe anything. The Treasury publishes a notice on its website and the Federal Reserve’s daily statement reflects the cancellation.

What to look at next

Before your next auction window, pull the Federal Reserve’s H.15 selected interest rates and find the 4-week or 8-week T-bill yield. That is the rate the market is pricing today, and it is the number your competitive bid will be measured against. Then check the Treasury’s auction calendar for the specific bill you want, the size being offered, and the bid cutoff time.

If you are parking a small amount for a few weeks, the noncompetitive path is the low-friction choice. You skip the rate-guessing, you cannot be rejected, and the economics are identical to a winning competitive bid. Save the competitive option for when you are trading size, or when you have a strong view that the clearing rate will come in below a level you are willing to accept.

The mechanics are not complicated. The discipline is in reading the auction results after the fact, comparing the stop-out to what you expected, and adjusting your next bid accordingly.

This article is general information, not financial advice. See our disclaimer.

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