---
title: Treasury Bills (T-Bills)
description: What Treasury bills are, the latest auction rate for every T-bill from 4 to 52 weeks, discount rate vs investment yield, and how to buy one.
source: Helious
canonical: https://helious.io/learn/treasury-bills
---

# Treasury Bills (T-Bills)

**Treasury bills** (T-bills) are short-term US government debt that matures in 4, 6, 8, 13, 17, 26 or 52 weeks. A bill pays no coupon: you buy it for less than its face value, get the full face value back at maturity, and the difference is your interest.

## How often T-bills are auctioned

Treasury sells every bill at auction each week, except the 52-week bill, which is auctioned every four weeks. Each auction is announced a few days ahead and the bills are issued a few days after it. Banks, dealers and funds set the rate with competitive bids. Most individual buyers send a non-competitive bid instead, which accepts whatever rate the auction sets. Helious publishes the latest rate and the usual auction day for every bill, and each bill's own page has its full auction history, bid-to-cover and bidder split.

## Discount rate and investment yield

A bill auction is quoted as a **discount rate**: the discount from face value, as an annual rate on a 360-day year. The **investment yield**, also called the coupon-equivalent or bond-equivalent yield, is the return on the price you actually pay, on a 365-day year. It is always a little higher than the discount rate, and it is the figure to compare with a CD, a savings account or a Treasury note.

## How to buy a Treasury bill

There are two routes. In a TreasuryDirect account, which the Treasury runs, you place a non-competitive bid before an auction and accept the rate it sets. In a bank or brokerage account you can bid at auction the same way, or buy bills that already trade in the secondary market at the going price. Bills are sold in $100 steps from a $100 minimum, and a non-competitive bid can be up to $10 million per auction. The interest is subject to federal income tax and exempt from state and local income tax.

## Why traders watch bill rates

Bill rates sit close to the [fed funds rate](https://helious.io/learn/fed-funds-rate) and move with what the market expects from the next few Fed decisions, so the strip from 4 to 52 weeks reads as the near-term rate path at auction prices.

## Questions

### What is a T-bill?

A T-bill, or Treasury bill, is a US government debt security that matures in 52 weeks or less. It is sold at a discount to its face value and pays the full face value at maturity, so the interest is the difference between the two. Bills come in 4, 6, 8, 13, 17, 26 and 52-week maturities.

### What is the 13-week Treasury bill rate?

It is the discount rate set at the most recent weekly auction of 3-month bills. Every 13-week auction result, with the bid-to-cover and bidder split, is on [the 13-week bill page](https://helious.io/auctions/13-week-bill).

### How do you buy Treasury bills?

Open a TreasuryDirect account and place a non-competitive bid before an auction, or buy through a bank or brokerage account, either at auction or in the secondary market. The minimum is $100, in $100 steps, and a non-competitive bid can be up to $10 million per auction.

### What is the difference between a T-bill's discount rate and its investment rate?

The discount rate measures the discount against face value on a 360-day year. The investment rate measures the return on the price paid on a 365-day year, so it is always a little higher. Compare the investment rate with a CD or a savings rate.

### Are T-bills taxed?

The interest is subject to federal income tax and exempt from state and local income tax.

## Live data

Helious publishes the current figures at [https://helious.io/learn/treasury-bills](https://helious.io/learn/treasury-bills), and through the get_auctions tool on its MCP server at https://helious.io/mcp.