Treasury Bill Minimum Purchase: How Much Do You Need?

The treasury bill minimum purchase amount at TreasuryDirect is $100 in face value, the lowest barrier to entry for direct government-backed short-term lending. If you buy through a broker or bank, minimums can be higher or nonexistent, depending on the institution. The key insight: because Treasury bills are sold at a discount, the amount you pay today is less than the $100 (or $1,000, $10,000) face value you receive at maturity.

The $100 TreasuryDirect minimum

TreasuryDirect, the U.S. Treasury’s direct purchase platform, allows you to buy Treasury bills in $100 increments in face value. This means you can purchase exactly $100, $200, $300, and so on—no rounding required. For individual savers and small investors, this low threshold is the most accessible entry point to Treasury securities.

The $100 face value minimum applies to all the Treasury bill maturities offered: 4-week, 8-week, 13-week (three-month), 26-week (six-month), and 52-week (one-year) bills. You open a free account at TreasuryDirect.gov, verify your identity and banking information, and bid in the next auction or buy directly from available inventory.

Understanding the discount: paid amount vs face value

This is the part that confuses new buyers. When you purchase a Treasury bill for $100 in face value, you do not pay $100 today. Instead, you pay a discount from par.

Here’s how it works. Suppose a 13-week Treasury bill with $100 face value is yielding 5% per annum. The discount on that bill is the interest you would earn over 13 weeks. Since 13 weeks is one-quarter of a year, the discount is roughly:

Discount = Face Value × Annual Yield × (Days to Maturity / 365)

Discount = $100 × 0.05 × (91 / 365) ≈ $1.25

So you pay approximately $98.75 today and receive $100 in 13 weeks. Your profit is $1.25, which annualizes to about 5%.

This discount-to-par structure is universal among T-bills. The amount you pay is always less than face value; the difference is your interest income. In the auction, you place a bid specifying how much face value you want to buy (in $100 increments), not the dollar amount you’ll pay. The Treasury calculates the payment based on the discount implied by your bid (or the market-clearing rate if you bid competitively).

Minimum purchases through brokers and banks

If you don’t want to use TreasuryDirect, you can buy T-bills through:

Securities brokers. Major firms like Fidelity, Schwab, E*TRADE, and others typically have $1,000 minimum face value purchases for T-bills on the secondary market (bills already issued, trading between investors). Some smaller or discount brokers have no stated minimum or as low as $0 for direct Treasury bids.

Banks. Some banks allow Treasury bill purchases through their wealth management or trust divisions, often with minimums of $5,000 or $10,000, and may charge a small fee.

Money market funds. If you want exposure to T-bills without committing to a specific minimum, you can buy shares of a money market fund that invests in Treasury bills. Fund minimums vary widely but are often $1,000 to $3,000 per account.

For most small investors, TreasuryDirect remains the lowest-friction and cheapest option, offering no trading fees, no commissions, and the lowest dollar minimum.

Why the discount matters for your total return

The discount amount varies daily based on auction results and market demand. When yields are high (as they have been in recent years), the discount is larger—you pay more of a cut-off price relative to face value. When yields are very low, the discount shrinks.

If you’re comparing two T-bill options or evaluating whether the yield justifies tying up your cash, the discount is embedded in the yield percentage. A “5% annual yield” on a 26-week bill, expressed as a simple discount, means you’re purchasing a roughly 2.5% discount from face value. The auction rate or market quote will always show this yield; you don’t need to calculate it yourself.

However, understanding the discount mechanism matters when you’re tracking your actual dollars. If you commit $10,000 to buy Treasury bills via TreasuryDirect, and you purchase $10,000 face value (100 × $100 increments), you will pay somewhat less than $10,000 from your account today, with the difference returned as earnings in 13 weeks, 26 weeks, or whenever your bills mature.

Non-competitive bids and guaranteed fills

TreasuryDirect allows non-competitive bidding, meaning you don’t specify a price or rate—you just say “I want $500 face value” and accept whatever rate the auction produces. This is the simplest path for small investors and avoids the risk of bidding too high and overpaying. The Treasury guarantees your purchase at the auction-clearing rate.

For $100 to $10,000 increments, non-competitive is standard. Competitive bidding (specifying your own discount rate) is available but is rarely worth the effort for small accounts; you’d need to understand the discount conventions and the current yield environment, and the benefit of a slightly better rate is tiny.

Holding to maturity vs selling early

When you hold a Treasury bill to maturity, the accounting is straightforward: you get your $100 (or whatever face value) back, and you’ve earned your discount as interest. But if you sell a T-bill on the secondary market before maturity, your gain or loss depends on interest rate moves. If rates have fallen since you bought, the bill is worth more (because it still carries the same yield in a lower-yield world); if rates have risen, it’s worth less.

This introduces reinvestment and interest-rate risk if you don’t hold to maturity. For risk-averse savers, holding to maturity is common, so the $100 minimum and discount structure simply mean: invest $99-ish today, get $100 in a few months, with no risk of price loss.

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