TreasuryDirect Guide: How to Buy I Bonds and T-Bills Without a Broker

Three numbers to start: 4.26% composite rate on I Bonds issued through October 2026, $10,000 annual purchase cap per Social Security Number, and a 45-day minimum hold on every T-Bill you buy through TreasuryDirect. Those three numbers explain why so many readers ask me about Treasury Direct and then quit halfway through the signup.

The platform looks like it was built in 2002 (because it basically was), and the redemption rules trip up even careful investors. But the math is real: a 4.26% inflation-protected yield with state-tax exemption, or T-Bills paying mid-3% with no broker spread. If you want those returns, you go directly to TreasuryDirect.gov. There’s no app, no fintech middleman, no expense ratio. This guide walks you through the account setup, the purchase flow, and the rules that catch people off guard.

Opening the TreasuryDirect account (the part everyone underestimates)

Setting up the account takes about 10 minutes if you have your documents ready. Going in cold and you’ll burn 45 minutes hunting for your bank routing number while the session times out. Before you start, get five things in one place:

1. Social Security Number and a current driver’s license or state ID.
2. Bank routing and account numbers for the checking account you’ll link.
3. Email address you actually check (account recovery happens here).
4. Employer name and address for the identity verification questions.
5. A device that isn’t your phone. The site is desktop-first; mobile is rough.

With those ready, go to TreasuryDirect.gov, click “Open an Account,” pick Individual, and answer the knowledge-based authentication questions. The system pulls from your credit file and asks about old addresses or loan amounts. Get one wrong and you may get locked out for 24 hours.

One detail that catches people: TreasuryDirect emails you an account number that looks like A-123-456-789. That’s your login, not a username you create. Save it somewhere permanent. I’ve had readers email me a year later asking how to log back in because they tossed the welcome email. Password resets on this platform are not fun.

Back at the bank we called this the “government website tax.” The interface is dated, the language is bureaucratic, and the user experience assumes you already know what you’re doing. Once you’re past setup, though, the friction drops dramatically and the buying flow becomes routine.

I Bonds: how the 4.26% rate actually works

The Series I Savings Bond pays a composite rate that combines a fixed rate (set when you buy and locked for the life of the bond) and a variable inflation rate that resets every six months. For bonds issued May 1, 2026 through October 31, 2026, the composite rate is 4.26%, built from a 0.90% fixed rate and a 3.34% annualized inflation rate. The Treasury announces new rates each May 1 and November 1, but each individual bond’s reset clock runs from its own issue date, not the calendar.

That fixed-rate component matters more than people realize. Two readers buying the same week can end up with very different long-term yields depending on the fixed rate in effect at purchase. A 0.90% fixed rate is the strongest we’ve seen in over a decade, and it sticks with the bond for 30 years. If inflation runs hot, the variable piece carries you; if inflation cools, the fixed rate keeps you ahead of a standard savings account.

The purchase limit is the constraint most people hit. You can buy $10,000 per Social Security Number per calendar year in electronic I Bonds via TreasuryDirect. A married couple can buy $20,000 combined. Trusts and certain entities have their own separate limits. And one rule change worth noting: as of January 1, 2025, the paper I Bond purchase via tax refund (the old $5,000 add-on) is permanently gone. Electronic-only from here on out.

T-Bills: the part that surprised me how easy it became

Treasury Bills are short-term debt sold at a discount and redeemed at face value at maturity. The difference is your yield. TreasuryDirect sells them in maturities of 4, 8, 13, 26, and 52 weeks, with a $100 minimum and $100 increments. In April 2026, shorter-maturity T-Bills were yielding in the 3.6%-3.7% range; the national average savings account was sitting around 0.38%-0.6% APY. That gap is why I keep telling readers with idle cash to look here first.

The purchase flow once your account is open: log in, click “BuyDirect,” pick “Bills,” choose your maturity, enter the amount, and select whether you want automatic reinvestment. A 4-week bill can be set to reinvest up to 25 times; a 26-week bill caps at 3 reinvestments. All reinvestment schedules are limited to a 2-year window. Auction results post after 5 PM ET on auction day, and the cash is debited from your linked bank account on the issue date. You’ll see the discount price reflected, and at maturity the full face value lands back in your TreasuryDirect cash holding.

There’s stuff the bank’s system shows that the customer never sees, and this is exactly that: when you buy a T-Bill, there’s a 45-day minimum holding period before you can transfer or sell it. This catches investors who think of T-Bills as cash equivalents. They are, once the 45 days clear. Reinvested securities don’t trigger a new 45-day clock; only fresh purchases do.

The redemption rules that catch people off guard

I Bond redemption rules are where I see the most frustration in reader emails. The headline rules:

• 12-month lockup. You cannot redeem any portion in the first year. None. Plan accordingly.
• 3-month interest penalty. Redeem between months 13 and 60, and you forfeit the most recent 3 months of interest.
• Penalty-free after 5 years. At month 60, the bond becomes fully liquid with no forfeiture.
• Partial redemptions in $25 increments. Minimum redemption is $25, and at least $25 must remain in the bond afterward.

A separate quirk worth knowing: TreasuryDirect does not display the most recent 3 months of accrued interest in your account balance until the bond crosses the 5-year mark. So your statement looks like it’s earning less than it actually is. The interest is there. The display just hides it as a built-in adjustment for the penalty period.

Federal tax treatment is one of the better-kept advantages. I Bond interest is exempt from state and local income tax across all 50 states. Federal tax can be deferred until you redeem the bond, hit final maturity at 30 years, or otherwise dispose of it. There’s also a federal exclusion available if you use the proceeds for qualified higher-education expenses, with income phase-outs that change annually.

Here’s the part nobody wants to tell you: that deferred federal interest all comes due in the year you redeem. If you’ve held bonds for 15 years and redeem a sizable position, the interest hits your tax return as a single-year lump. That can bump you into a higher bracket. I’ve seen readers stagger redemptions across two or three tax years specifically to manage this.

The 30-day playbook

I Bonds and T-Bills aren’t competing products. They’re a barbell. T-Bills are your liquid sleeve once the 45-day fuse burns off. I Bonds are your inflation-hedged base that you build over years through the $10,000 annual cap. Readers who treat them as substitutes usually pick wrong; readers who pair them keep cash working at every horizon.

Three profiles, three plays:

• Emergency fund builder, under 35: open the account this month, start with a single 4-week T-Bill at $500 to learn the auction flow, then layer in an I Bond purchase of $1,000-$2,500 once you’re comfortable.
• Cash-heavy saver, 35-55: max the $10,000 I Bond cap by year-end, then build a T-Bill ladder with 4-week and 13-week rungs for the rest of your idle cash.
• Pre-retiree, 55+: stagger I Bond purchases across multiple years and SSNs (yours and a spouse’s) to spread the eventual interest realization across tax years.

The one mistake that ruins this: treating I Bonds as a liquid emergency fund. The 12-month lockup is absolute. I’ve had readers buy in March planning to redeem in October when a car broke down, and the system simply won’t let them. Build the I Bond position with money you’re confident you won’t need for 12+ months, and keep your true emergency cash in a high-yield savings account or short T-Bills with the 45-day clock already cleared. Second complication: forgetting which bonds are inside the 3-month penalty window. Keep a simple spreadsheet of issue dates so you redeem the oldest bonds first when the time comes.

This weekend, do three things. Pull your bank’s routing and account numbers, write down your TreasuryDirect plan in one sentence (target dollar amount, target month), and open the account at TreasuryDirect. Then bookmark the rate announcement page so you check it every May 1 and November 1. If you want to verify any rule mentioned here against the source, the consumer page at Consumer Financial Protection Bureau cross-references the Treasury rules in plain English.