What Are Treasury Bills (T-Bills)?
Treasury bills, or T-bills, are short-term loans you make to the US government. You buy one for less than its face value, and the government pays you the full amount back within a year. The difference between what you paid and what you get back is your interest.
How do Treasury bills work?
Lending money to the most powerful government on earth sounds complicated, but the mechanics are surprisingly simple. When you buy a Treasury bill, you are handing the US government cash today in return for a promise to be paid a fixed amount back on a set date, always within a year. T-bills are how the government borrows money for short stretches to cover its day-to-day spending.
The clever part is how the interest is paid. A T-bill does not send you regular payments. Instead, you buy it at a discount, for less than its face value, and at maturity you receive the full face value. That gap is your entire return.
The Analogy
Buying a $100 gift card for $98
Imagine a shop sells you a $100 gift card but only charges you $98 for it, on the condition that you cannot spend it for three months. When the three months are up, the card is worth its full $100. You put in $98 and walked away with $100, so you earned $2 simply for waiting. A Treasury bill works the same way: you pay less than the face value now and collect the full amount later, and the difference is your profit.
How is the return on Treasury bills calculated?
There is no interest rate printed on the bill. Your return comes entirely from buying low and being repaid at full value, so the size of the discount sets how much you earn.
| Amount | |
|---|---|
| Face value (paid at maturity) | $1,000 |
| Price you pay today | $980 |
| Your return | $20 |
Note: This is a simplified, hypothetical example created strictly for educational purposes.
The deeper the discount, the higher your effective yield. Because T-bills are sold through regular public auctions, that discount is set by how much investors collectively are willing to pay, which moves up and down with broader interest rates.
Why do Treasury bills matter?
T-bills are treated as one of the safest places in the world to park cash for a short time, which gives them an outsized role in finance.
Why It Matters
The benchmark for safety
Because they are backed by the US government's ability to tax and print its own currency, T-bills are widely viewed as carrying very low risk of default. That reputation makes their yield a kind of baseline that the rest of the market measures itself against when judging the return on lending with almost no chance of loss. Big institutions, companies, and funds use T-bills as a safe holding place for cash they may need soon, which is part of why they are central to how money moves through the system.
What are the risks of Treasury bills?
Very low risk is not the same as no risk, and the trade-off for that safety is a modest return.
Red Flags & Pitfalls
Safety has a price
The main catch is that the low risk comes with low returns, which may not keep up with inflation. If prices are rising faster than your T-bill yield, the cash you get back buys less than the cash you put in, so you can quietly lose purchasing power even while earning interest. T-bills are built for safety and short-term parking of cash, not for growing wealth over the long run, and treating them as a growth investment misunderstands what they are for.
The TL;DR for Treasury Bills (T-Bills)
At a Glance
Key Takeaways
- A Treasury bill is a short-term loan to the US government that is repaid in full within a year.
- You buy it at a discount and receive the full face value at maturity; the difference is your return.
- They are seen as one of the safest holdings available, so their yield is used as a baseline for the market.
- The trade-off for that safety is low returns that may not keep pace with inflation.