What Is a Bill Auction?

Bill auction is a public auction for Treasury bills that is held weekly by the U.S. Treasury. As of 2019, there are 24 authorized primary dealers that are required to bid directly upon each issue. This is the manner in which all U.S. Treasury bills are issued.

Bill Auction Explained

Treasury bills (T-bills) are short-term debt securities issued by the U.S. government through the Treasury Department to help finance the national debt. These debt instruments mature within a year and are issued at a discount to par value. The maturity term for T-bills are: 1 month (or 4 weeks), 3 months (or 13 weeks), 6 months (or 26 weeks), and 1 year (or 52 weeks). The minimum amount you can buy a bill for is $100, although the most commonly sold bills have a par between $1,000 and $10,000. The bills are considered risk-free securities since they are backed by the full faith and credit of the U.S. government and, hence, the yield on these securities is used as the benchmark for short-term interest rates. Treasury bills are issued in electronic form through an auction bidding process which is conducted every week.

Auction Announcement

An announcement is released several days before the bill auction to kickstart the process. The announcement includes information such as the auction date, issue date, amount of security that will be sold, bidding close times, participation eligibility, etc. All auctions are open to the public through Treasury Direct or the Treasury Automated Auction Processing System (TAAPS).

Role of Primary Dealers

The bill auction accepts competitive bids to determine the discount rate to be paid on each issue. A group of securities dealers, known as primary dealers, are authorized and obligated to submit competitive bids on a pro-rata share of every Treasury bill auction. The winning bid on each issue will determine the interest rate that is paid on that issue. Once an issue is purchased, the dealers are allowed to hold, sell, or trade the bills. The demand for bills at auction is determined by market and economic conditions.

Bill Auction Participants

Participants in any Treasury auction consist of small investors and institutional investors who submit bids categorized as either competitive or non-competitive tenders. Non-competitive tenders are submitted by smaller investors who are guaranteed to receive bills, but they won’t know what discount rate they will receive until the auction closes. In effect, these investors receive no guarantee on the price or discount received. An investor who submits a non-competitive bid agrees to accept whatever discount rate is decided at the auction, determined by the competitive side of the auction which is handled as a Dutch auction. The minimum non-competitive tender for a Treasury bill is $10,000. The non-competitive closing time for bills is normally 11:00 a.m. Eastern Time on auction day.

Competitive bidders are not guaranteed to receive securities as bid approval depends on the discount yields that are submitted. A competitive tender is submitted by bigger investors, such as institutional investors. Each bidder is limited to 35% of the amount of the offering per bill auction. Each bid submitted specifies the lowest rate or discount margin that the investor is willing to accept for the debt securities. The bids with the lowest discount rate will be accepted first. The lowest discount rate which meets the supply of debt being sold serves as the “winning” yield or the highest accepted yield, after all non-competitive bids have been subtracted from the total amount of securities offered. All investors who bid at or above the level of the winning yield receives securities with this discount rate. All bidders, competitive and non-competitive, will receive this yield.

The competitive closing time for bills is normally 11:30 a.m. Eastern Time on auction day.

The Auction Process

For example, suppose the Treasury seeks to raise $9 million in one-year T-bills with a 5% discount rate. Let's assume the competitive bids submitted are as follows:

$1 million at 4.79%

$2.5 million at 4.85%

$2 million at 4.96%

$1.5 million at 5%

$3 million at 5.07%

$1 million at 5.1%

$5 million at 5.5%

The bids with the lowest discount rates will be accepted first since the government will prefer to pay lower yields to investors. In this case, since the Treasury is looking to raise $9 million, it will accept the bids with the lowest rates up to 5.07%. At this mark, only $2 million of the $3 million bid will be approved. All bids above the 5.07% rate will be accepted, and bids below will be rejected. In effect, this auction is cleared at 5.07%, and all successful competitive and non-competitive bidders receive the 5.07% discount rate.

On issue day, Treasury delivers T-bills to non-competitive bidders who made their submissions in a particular bill auction. In exchange, Treasury charges the accounts of those bidders for payment of the securities. The purchase price of the T-bill is listed on the bill auction results press release and is expressed as a price per hundred dollars.