You can buy Treasury bills directly from the government at TreasuryDirect.gov, or through a brokerage or bank account. T-bills are only available in electronic form.

Some online brokers allow you to purchase individual T-bills, and some offer Treasury accounts, which do the work of purchasing T-bills for you, holding them to maturity, and then reinvesting the profits.

Whether you buy your T-bills from TreasuryDirect or from a financial institution, you’ll need to set up an account, and link your bank for payment.

Then, decide which maturity of T-bill you want to buy.

The government sells T-bills that mature in four, six, eight, 13, 17, 26 or 52 weeks. Brokers may offer all of these maturity lengths, or only select terms.

T-bills are typically sold at a discount to their face value, and this discount determines the yield you’ll earn by holding a bill to maturity. For example, if you bought a four-week, $100 Treasury bill at a discount, you’d pay the discounted price, then get the full $100 at the end of the four weeks.

TreasuryDirect.gov sells Treasury bills online at auction, and a minimum bid of $100 is required. Brokerages may ask for higher or lower minimums, depending on the account.

T-bills are considered a relatively safe short-term investment because they are backed by the U.S. government, and guaranteed to pay out when held for the full term.

You can also invest in T-bills indirectly through Treasury ETFs or mutual funds.