What Is a Treasury Bill? T-Bills Explained (2026)

What Is a Treasury Bill? A Plain-English Explainer

If you’ve ever wondered what is a treasury bill and whether it has any place in your financial plan, you’re not alone. T-bills are one of the most widely discussed yet least understood investments for beginners. They sound complicated, but the core idea is refreshingly simple – and by the end of this guide, you’ll know exactly how they work, what they pay, and how to buy one if you decide to.

The Simple Definition of a Treasury Bill

A treasury bill (commonly shortened to T-bill) is a short-term debt security issued by the US Department of the Treasury. When you buy one, you are essentially lending money to the US federal government for a fixed period. In return, the government promises to pay you back the full face value when the bill matures.

Here’s the key twist: you don’t buy a T-bill at face value. You buy it at a discount – meaning you pay less than the bill is worth at maturity. The gap between what you pay today and what you receive at the end is your return. No coupon payments, no monthly interest cheques – just a lump sum at maturity.

A Quick Illustrative Example

Imagine a hypothetical 26-week T-bill with a face value of $1,000. You might purchase it for $975 (this is a made-up illustration – actual prices vary with market conditions). At maturity, the government pays you $1,000. Your return is $25 on a $975 investment over six months. Annualised, that becomes your effective yield.

How Long Do Treasury Bills Last?

T-bills are specifically the short-term end of the US government debt market. The Treasury issues them in the following standard maturities:

• 4 weeks (approximately one month)
• 8 weeks (approximately two months)
• 13 weeks (approximately three months)
• 17 weeks (approximately four months)
• 26 weeks (approximately six months)
• 52 weeks (approximately one year)

For anything longer than a year, the Treasury issues Treasury notes (2-10 years) or Treasury bonds (20-30 years). T-bills are always one year or less – that short timeframe is a defining feature.

Treasury Bills vs. Other Government Securities

It helps to see how T-bills compare to their siblings in the government debt family:

• Treasury Bills (T-bills): Maturity up to 52 weeks. Sold at a discount. No periodic interest payments.
• Treasury Notes (T-notes): Maturity of 2, 3, 5, 7, or 10 years. Pay semi-annual coupon interest.
• Treasury Bonds (T-bonds): Maturity of 20 or 30 years. Pay semi-annual coupon interest.
• TIPS (Treasury Inflation-Protected Securities): Principal adjusts with inflation. Worth exploring if you’re concerned about rising prices – our guide on what inflation is and how it affects your money explains the risk TIPS are designed to address.

Why Do People Buy Treasury Bills?

T-bills won’t make you rich quickly, and that’s precisely the point for many investors. Here are the most common reasons people buy them:

Safety and Stability

T-bills are backed by the full faith and credit of the US government, which has never defaulted on its short-term obligations. The US Securities and Exchange Commission’s investor education site recognises Treasury securities as among the safest instruments available to retail investors. This makes T-bills a popular choice for emergency funds or money you can’t afford to lose.

Short Time Commitment

Unlike a 10-year bond, a 4-week T-bill ties up your cash for less than a month. That liquidity is useful for investors who want a return on idle cash without locking it away long-term.

Tax Advantage

Interest income from T-bills is exempt from state and local income tax, though it is subject to federal income tax. For investors in high state-tax locations, this can make T-bills more attractive than equivalent bank savings rates on an after-tax basis.

What Are the Risks?

T-bills are low-risk but not no-risk. Every beginner investor should understand these caveats:

• Inflation risk: If inflation rises above your T-bill yield, your purchasing power actually shrinks in real terms. Learn more about this dynamic in our beginner’s article on what inflation means for your savings.
• Opportunity cost: When stock markets perform strongly, T-bills may significantly underperform. Investors who hold too many T-bills may miss out on long-term growth available through diversified equity exposure – for example, through beginner-friendly index funds that spread risk across hundreds of companies.
• Interest rate sensitivity: If you need to sell your T-bill before maturity on the secondary market, rising interest rates could mean you receive less than you expected.

How to Buy a Treasury Bill

There are two main routes for buying T-bills in the United States:

1. TreasuryDirect.gov (Direct from the Government)

The US Treasury runs TreasuryDirect.gov, a free online platform where you can purchase T-bills directly with no brokerage commission. The minimum purchase is $100, and you can buy in $100 increments. New T-bills are sold at regular auctions, and you can set up an account and participate in non-competitive bids, meaning you accept whatever yield the auction determines. This is the most cost-effective route for most beginners.

2. Through a Brokerage Account

Major brokerages including Fidelity, Charles Schwab, and Interactive Brokers allow you to buy new-issue T-bills at auction and trade existing T-bills on the secondary market. Buying through a brokerage integrates T-bills alongside your other investments and can make managing a diversified portfolio more convenient. Check each provider’s current fee schedule before you open an account, as pricing can change.

T-Bills and Your Broader Portfolio

T-bills are a tool, not a complete strategy. For most beginners building long-term wealth, they work best as a place to park cash you’ll need within the next year – think an emergency fund buffer or money earmarked for a near-term goal. For money you won’t need for five or more years, many financial educators suggest a diversified approach that includes equities alongside bonds.

If you’re just starting to invest and wondering how to build a broader portfolio, our guide to the best index funds for beginners is a practical next step.

Actionable Takeaways for Beginners

1. Understand the discount structure: you buy below face value and receive full face value at maturity – that gap is your yield.
2. Compare T-bill yields to your high-yield savings account. Sometimes one is better than the other; check current rates before deciding.
3. Use TreasuryDirect.gov if you want to avoid fees entirely. Set up a non-competitive bid at the next weekly auction.
4. Don’t ignore inflation. A T-bill yielding less than the current inflation rate loses real purchasing power.
5. Think of T-bills as part of a bigger picture – not as a standalone wealth-building strategy.

This article is for educational purposes only and does not constitute personalised financial advice. All investments carry risk. Always consult a qualified financial professional before making investment decisions.

Frequently Asked Questions

What is a treasury bill in simple terms?

A treasury bill is a short-term loan you make to the US government. You buy the bill at a discount, and when it matures – after 4, 8, 13, 17, 26, or 52 weeks – the government pays you the full face value. The difference between what you paid and what you received is your return.

Are treasury bills safe?

T-bills are backed by the full faith and credit of the US government, making them one of the lowest-risk investments available to retail investors. However, they are not completely risk-free – inflation can erode the real value of your return over time, and if you sell a T-bill before maturity on the secondary market, you may receive less than face value depending on prevailing interest rates.

How do I buy a treasury bill?

You can buy T-bills directly from the US government at TreasuryDirect.gov with no fees and a minimum of $100. Alternatively, you can buy them through a brokerage account at firms like Fidelity, Charles Schwab, or Interactive Brokers. Check each provider’s current terms before committing.

Do treasury bills pay interest?

T-bills do not pay traditional periodic interest the way bonds do. Instead, you buy them at a price below face value and receive the full face value at maturity. The difference between what you paid and what you receive is effectively your interest income, and it is subject to federal income tax but generally exempt from state and local taxes.

This article is for educational purposes only and does not constitute financial or investment advice. Investing involves risk, including the possible loss of principal. Past performance does not guarantee future results. Always do your own research, and consider speaking with a licensed financial professional before making investment decisions.