What Are T Bills and How Do They Work
T bills are one of the simplest ways to lend money to the U.S. government and earn a return over a short period of time. They do not pay interest the way a savings account or bond coupon does. Instead, you buy them for less than their face value, then receive the full face value when they mature.
That simple structure is why Treasury bills, often called T bills, show up in conversations about cash management, emergency funds, and low-risk investing. They are short-term U.S. government securities backed by the full faith and credit of the United States.
This article is for general education only and is not personal financial advice. Rates, taxes, and account rules can change, so check current details before making investment decisions.
What a T bill is
A T bill is a short-term debt security issued by the U.S. Department of the Treasury. When the government sells a T bill, it is borrowing money from investors. In return, the investor receives a promise that the government will pay the bill’s full face value at maturity.
T bills are issued with maturities of one year or less. Common maturities include:
4 weeks
8 weeks
13 weeks
17 weeks
26 weeks
52 weeks
The face value is the amount paid back at maturity. If a T bill has a face value of $1,000, the investor receives $1,000 when it matures.
The purchase price is usually lower than the face value. The difference between what you pay and what you receive later is your earnings.
For example, if you buy a $1,000 T bill for $980 and hold it until maturity, you receive $1,000. Your return is $20 before taxes.
That is the core idea. You earn by buying at a discount and getting paid the full amount later.
How T bills work
T bills do not make monthly or quarterly interest payments. This makes them different from many traditional bonds.
Here is the basic path:
The Treasury issues a T bill.
Investors buy it at auction or through a broker.
The T bill matures after its set term.
The investor receives the full face value.
The yield depends on the price paid. If investors pay a lower price for the same face value, the yield is higher. If they pay closer to face value, the yield is lower.
A simple example
Suppose you buy a 26-week T bill with a $1,000 face value.
You pay $975. Six months later, the Treasury pays you $1,000.
Your earnings are $25.
That does not mean the annual yield is exactly 2.5 percent, because the holding period is only about half a year. Treasury yields are usually quoted on an annualized basis, which helps investors compare a 4-week bill with a 26-week bill or a 52-week bill.
The math behind quoted yields can get technical, but the practical idea is simple. The bigger the discount relative to the time you hold the bill, the higher the return.
Why investors use T bills
T bills are popular because they combine short maturities with strong credit backing. They are often used by people who want a place to hold cash without taking on the same level of risk as stocks or long-term bonds.
Common uses include:
Holding part of an emergency fund
Parking money for a near-term purchase
Earning a return on cash that is not needed right away
Building a short-term bond ladder
Reducing exposure to stock market swings
They can also be useful when savings account rates are lower than Treasury yields. That said, bank accounts and T bills are not identical. A savings account may offer easier access to cash, while a T bill has a fixed maturity unless sold early.
T bills compared with savings accounts and CDs
T bills often get compared with high-yield savings accounts and certificates of deposit, or CDs. All three can play a role in conservative cash planning, but they work differently.
Feature | T bills | Savings accounts | CDs |
Issuer | U.S. Treasury | Bank or credit union | Bank or credit union |
Typical term | 1 year or less | No fixed term | Fixed term |
Return style | Bought at a discount | Interest credited | Interest paid or credited |
Early access | Sell before maturity if needed | Usually easy | May have penalties |
Federal tax | Yes | Yes | Yes |
State and local tax | Usually exempt | Usually taxable | Usually taxable |
A savings account is usually best for cash you may need at any time. A CD may work if you are comfortable locking up money for a fixed term. A T bill can sit between the two, especially for money that has a specific time horizon.
How to buy T bills
There are two common ways to buy T bills in the United States: directly through TreasuryDirect or through a brokerage account.
Buying through TreasuryDirect
TreasuryDirect is the government’s own platform for buying Treasury securities. Investors can open an account and buy T bills at auction.
The process generally looks like this:
Open a TreasuryDirect account.
Choose the maturity you want.
Enter the amount you want to buy.
Place a noncompetitive bid.
Wait for the auction result.
Hold the T bill until maturity or manage it through the account.
A noncompetitive bid means you agree to accept the yield set at auction. Most individual investors use this approach because they do not need to guess or compete on price.
TreasuryDirect can be useful for buy-and-hold investors. The tradeoff is that the interface may feel less familiar than a brokerage platform, and selling before maturity is not as simple as clicking a sell button in a brokerage account.
Buying through a brokerage
Many major brokerages let customers buy new T bills at auction or buy existing T bills on the secondary market.
A brokerage account may be more convenient if you already invest there. It can also make it easier to sell a T bill before maturity, although the sale price can rise or fall based on current market rates.
When using a brokerage, pay attention to:
Minimum purchase amounts
Any fees or markups
Whether you are buying at auction or on the secondary market
The maturity date
The yield shown
Whether cash is automatically reinvested
For many investors, the choice comes down to comfort. TreasuryDirect is direct and government-run. Brokerages may offer a smoother interface and more flexibility.
What happens at a Treasury auction
T bills are sold through regularly scheduled Treasury auctions. Large institutions and individual investors can participate.
There are two types of bids:
Noncompetitive bids
This is the common route for individual investors. You state how much you want to buy and accept the auction’s final rate.
Competitive bids
This is usually used by institutions or experienced investors. The bidder states the yield they are willing to accept. If the bid is too low, it may not be filled.
After the auction, the Treasury determines the price and yield. If your noncompetitive order is accepted, the purchase settles, and the T bill appears in your account.
At maturity, the Treasury pays the face value. If you bought through TreasuryDirect, the money goes to your linked bank account or can be reinvested if you selected that option. If you bought through a brokerage, the money usually returns to your brokerage cash balance.
How T bill returns are taxed
T bill earnings are subject to federal income tax. They are generally exempt from state and local income taxes.
That state tax treatment can make T bills more attractive for investors in higher-tax states, compared with bank interest that is usually taxed at federal, state, and local levels.
The income is usually reported in the year the T bill matures or is sold, rather than when purchased. If you buy through TreasuryDirect or a brokerage, you should receive tax reporting forms that show the taxable amount.
Tax rules can vary by situation. If tax treatment matters to your decision, check IRS guidance or speak with a qualified tax professional.
The main benefits of T bills
T bills are not exciting, and that is part of their appeal. They are designed for stability and short-term use.
They have strong credit backing
T bills are backed by the U.S. government. That makes them among the lowest credit-risk investments available in U.S. dollars.
This does not mean they are risk-free in every possible way, but the risk of the Treasury failing to pay as promised has historically been viewed as very low.
They mature quickly
Because T bills mature in a year or less, investors do not have to wait long to get face value back if they hold to maturity.
Short maturities can be helpful when planning for known expenses, such as:
Property taxes
Tuition payments
A car purchase
A down payment
A large insurance premium
They are simple to understand
T bills have a clear structure. You buy below face value and receive face value later. There are no company earnings reports, stock dividends, or long-term projections to analyze.
They may help reduce portfolio swings
T bills can act as a steadier part of a broader portfolio. They will not provide the long-term growth potential of stocks, but they can help preserve cash for short-term needs.
The risks and tradeoffs to know
T bills are low risk, but they are not perfect. The biggest mistake is treating them like a savings account with no tradeoffs.
You may need to wait for maturity
If you hold a T bill until maturity, the process is straightforward. If you need cash before then, you may have to sell it.
Selling before maturity can be easy in a brokerage account, but the price depends on market conditions. If interest rates have risen since you bought the T bill, your bill may be worth less in the secondary market.
Reinvestment risk can affect your future return
Short maturities mean money comes back quickly. That is useful, but it also means you may need to reinvest at whatever rates are available at that time.
If rates fall, a new T bill may offer a lower yield than the one that just matured.
Inflation can reduce purchasing power
T bills can help preserve nominal dollars, but inflation can eat into real returns. If inflation is higher than the T bill yield, your money may lose purchasing power even though the dollar amount grows.
They are not built for long-term growth
T bills are cash-like tools. They are not meant to replace long-term investments for goals that are many years away.
A portfolio made only of T bills may feel safe, but it may not grow enough to keep up with long-term needs.
What a T bill ladder is
A T bill ladder is a simple strategy where you buy T bills with different maturity dates. As each bill matures, you can use the cash or buy another bill.
For example, you might split $4,000 into four parts:
$1,000 in a 4-week T bill
$1,000 in an 8-week T bill
$1,000 in a 13-week T bill
$1,000 in a 26-week T bill
As the shortest bill matures, you can decide whether to spend the money, keep it in cash, or reinvest it.
A ladder can help balance access and return. You avoid putting all your money into one maturity date, and you create regular points where cash becomes available.
This approach can be useful for emergency funds, but only if enough cash remains immediately available for urgent needs. A surprise expense does not always wait for the next maturity date.
How to read T bill yields without getting lost
T bill quotes can look confusing at first because they may show several numbers. The most useful figure for many investors is the yield, often shown as an annualized rate.
When comparing options, look at:
Maturity date
This tells you when the Treasury pays the face value.
Price
This shows what you pay now for the future face value.
Yield
This helps compare one T bill with another, even if they have different maturities.
Settlement date
This is when the purchase becomes official and the money leaves your account.
Minimum purchase amount
Treasury securities often use $100 increments, but platforms may set their own rules or display requirements differently.
If you are buying through a brokerage, confirm whether the yield shown is after any fee or markup. Small differences matter more when the investment period is short.
When T bills can make sense
T bills may be a good fit when the goal is capital preservation over a short period. They are especially useful when the money has a job and a timeline.
They can make sense for:
Cash you do not need this week, but may need within a year
Money set aside for a specific upcoming expense
A conservative slice of a larger investment plan
Investors who want direct exposure to U.S. Treasury securities
People in states where the state tax exemption is valuable
They may not make sense for:
Cash needed at any moment
Long-term retirement growth by themselves
Investors who cannot tolerate any price movement if selling early
People who prefer FDIC-insured bank deposits for simplicity
Anyone who does not want to manage maturities or reinvestment
A quick checklist before buying
Before buying your first T bill, answer a few practical questions:
When will you need the money?
Are you comfortable holding until maturity?
Are you buying through TreasuryDirect or a brokerage?
Do you understand the yield shown?
What happens to the cash at maturity?
Do you want automatic reinvestment?
How will federal taxes affect the return?
Does the state tax exemption matter for you?
The best T bill maturity is not always the one with the highest yield. The right choice should match the timing of your cash need.
The takeaway
T bills are short-term U.S. government securities that let investors earn a return by buying below face value and receiving full face value at maturity. They are simple, widely used, and backed by the U.S. Treasury.
Their strengths are clear: short maturities, strong credit quality, and predictable payoff if held to maturity. Their tradeoffs are also clear: limited long-term growth, reinvestment risk, inflation risk, and possible price changes if sold early.
For money you need soon, a T bill can be a useful tool. For money you need years from now, it is usually only one part of a broader plan. The smart move is to match the maturity to the purpose, keep enough cash available for immediate needs, and understand exactly when your money comes back.
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