T-Bill Auto-Roll: TreasuryDirect vs Fidelity, and How to Turn It Off

There is a specific moment when a T-bill ladder starts to feel like it runs itself. You set it up, you watch the first few maturities land and roll into the next rung without you touching anything, and you start treating the whole structure the way you’d treat a savings account on autopilot. That feeling is mostly earned, but it hides two decisions that are still yours to make, and they are not the same decision on every platform. One is what happens to the money if the new bill costs more than the old one paid out. The other is what happens to the interest you already earned. Get comfortable with the autopilot before you know the answers, and you can end up with a ladder that quietly drains cash or one that stops compounding without ever sending you an alert.

The short answer: on TreasuryDirect, auto-reinvestment is a setting you can choose when you buy the bill or add afterward, and you can edit or cancel it right up until four business days before the next auction — but if you owe more for the new security than the maturing one pays, which for a bill typically comes from tax withholding you asked for rather than from a yield move, TreasuryDirect will either pull the difference from your linked funds or cancel the roll outright. On Fidelity, enrolling in Auto Roll happens at the moment you place the original order, and while you can drop out later with no penalty, only the maturing principal gets rolled — the interest is dropped into your account as cash and never automatically reinvested on either platform. Turning Fidelity’s version off is a button on the position, with one deadline that matters: the day before the replacement bill’s auction.

TreasuryDirect: a decision you can still change

TreasuryDirect lets you schedule reinvestment when you buy a security or layer it on afterward, “at any time up to four business days before the original security matures,” and you can revisit that choice for as long as the reinvestment window stays open. The path to change or cancel a scheduled roll is Manage Direct → Manage My Securities → Edit reinvestments. Bills get the most flexibility in the system: TreasuryDirect states that “bills may be scheduled for multiple reinvestments, up to two years,” while “notes, bonds, and FRNs can only be scheduled for one reinvestment.” That asymmetry is worth sitting with if your ladder mixes maturities, because a 26-week bill you plan to roll for a year needs to be re-scheduled less often than you’d guess, but a note you’re rolling once will need your attention again once that single reinvestment executes.

The roll itself is narrow by design. TreasuryDirect requires that “the type of security must be the same,” so a 13-week bill only ever rolls into another 13-week bill — there’s no built-in way to auto-migrate from a 13-week rung into a 26-week rung just because rates moved. If you want to reshape the ladder, that has to happen by hand.

The part that catches people off guard is the deadline. TreasuryDirect “closes the option to reinvest four business days before the relevant auction,” and the flip side of that is your leverage: “you can change or cancel a reinvestment, as long as it’s more than four business days before the new auction.” Four business days sounds generous until you realize it’s counted against the auction date, not the maturity date, and those two dates aren’t identical. If you’re watching a Fed decision or a jobs report and thinking about whether to keep a rung rolling into short bills or redirect it, that four-day window is the actual clock you’re working against, not the calendar reminder most people set for the maturity date itself.

Since October 28, 2026, reaching that Edit reinvestments screen requires signing in through ID.me. TreasuryDirect says scheduled reinvestments keep running for account holders who have not set up ID.me, but that they cannot view, edit or cancel them until they do, and its FAQ lists no paper alternative for that step; the details are in TreasuryDirect without ID.me.

Then there’s the money mechanic that makes TreasuryDirect genuinely different from a brokerage sweep. Because reinvestment happens at auction, the new bill’s price isn’t fixed when you schedule the roll — it’s set by that auction’s yield. TreasuryDirect is explicit that “you may owe more for the new security than you are getting for your maturing security,” and the fix is on you: “make sure funds are available in your bank account or C of I to cover the difference before the issue date.” Skip that step and the system doesn’t extend you credit. “If funds are not available to pay the difference, we will cancel the reinvestment and deposit the proceeds of the maturing security into your bank account or C of I.” For a bill, though, a yield move alone can’t open that gap: TreasuryDirect sells bills “at a discount or at par (face value)” and pays face value at maturity, and the reinvestment rolls that principal, so the realistic trigger is the other cause it lists, money you’ve told it to withhold to pay estimated taxes. If that withholding leaves your linked account a little light, a ladder can un-ladder itself silently. One more boundary worth knowing: TIPS aren’t part of any of this. You can reinvest bills, notes, bonds, and FRNs on TreasuryDirect, but not TIPS — if you’re holding inflation-protected securities, rolling them is a manual rebuy every time, and it’s worth reading up on how TIPS phantom income gets taxed before you decide whether TreasuryDirect is even the right home for them. If your plan involves buying more bills through TreasuryDirect in the first place, the mechanics of how to buy through TreasuryDirect are the logical starting point.

Fidelity: the checkbox that ships with the order

Fidelity’s Auto Roll program is tied to a single point in the timeline. Instead of a setting you can also add after the fact, as on TreasuryDirect, it’s built into the purchase itself: you enroll by choosing to “select Yes on the Auto Roll option displayed on the order entry screen,” after agreeing to the Auto Roll Service Agreement and the accompanying alerts. There’s no separate trip to a settings page after the fact — the decision is made, or not made, in the same click that buys the bill.

Eligibility is narrower than “any Treasury you own.” Fidelity limits Auto Roll to “Treasury auction securities, new-issue CDs with a term to maturity of 5 years or less,” while excluding TIPS, CMBs, and anything purchased on the secondary market rather than at a new issue. There’s also a ceiling, but it sits on the CD side: Fidelity lists “CD purchases exceeding $250,000” as ineligible, which matters if a CD rung in your ladder could bump against that limit, while the program page sets no such dollar cap on Treasury auction purchases.

The mechanic that most resembles a trap, if you don’t read past the headline feature, is what actually gets rolled. Fidelity states plainly that “only the maturing principal will be applied to any subsequent Auto Roll position purchase” and that “no interest payments from these positions will be included in any Auto Roll position purchase.” The interest lands in your account as ordinary cash, available to spend, hold, or manually reinvest, but it will not compound into the next rung on its own. Run a ladder on Auto Roll for a year without ever sweeping that cash back in, and the ladder itself stays exactly the size it started at while a slowly growing pile of un-invested interest sits next to it. The one thing Fidelity does make easy is opting back out: “you have the ability to withdraw from the service at any time with no penalties,” so if a particular rung needs to become cash instead of rolling again, canceling that position’s participation is straightforward. One clarification worth making explicitly, because Fidelity’s own materials can blur it: the rule about a “settlement date within twelve calendar days following stated maturity date” applies to the CD side of Auto Roll, not to Treasuries. For a maturing Treasury, the service looks for a new auction whose settlement date matches the old bill’s maturity date, and if it finds none it keeps searching for one settling up to three calendar days after maturity; that twelve-day settlement language isn’t the mechanism governing your T-bill rungs, and treating it as if it were is a good way to misjudge how quickly a roll actually executes.

How to turn off Auto Roll at Fidelity

Enrollment happens on the order ticket, but leaving does not require a new order. Fidelity’s Auto Roll Service Agreement says the service “will continue until you affirmatively cancel” it, and gives three ways to do that, depending on how much you want to stop.

What you want to stop	Where to do it	Deadline
One rung only	Positions page → select the row of the bill or CD → Cancel Auto Roll	Before the replacement order fills
Every Auto Roll position in an account	Unsubscribe that account from the Alerts Service; the agreement says this revokes the instructions and cancels the service for that account	Before the replacement order fills
A replacement purchase already generated	Orders page → cancel the open order, or call Fidelity at 800-544-5372	Treasuries: end of the day before the auction

The timing is the part that trips people up. Fidelity generates the replacement order ahead of the maturity, not on the maturity date, and its Auto Roll FAQ says the order “typically” fills “7 to 10 days before the bond or CD’s maturity but can happen sooner.” For Treasuries, “you can cancel the purchase up until the end of the day prior to auction date,” and after the new order has filled, “it cannot be canceled.” So the practical check before you rely on a rung turning into cash is the Activity & Orders page: if a replacement purchase is already listed there, canceling Auto Roll on the position is no longer enough, and the open order itself has to be canceled before the auction. If it has already filled, the money is committed to the new bill, and getting cash out early means selling it on the secondary market instead.

Two more details from the agreement are worth knowing before you count on the roll continuing. Fidelity reserves the right to skip a reinvestment when the expected yield of the bill to be auctioned is below 0%, and it notifies you through the Alert Service on auction day when that happens. And if the service cannot find a matching auction in its search window, it cancels itself and leaves the proceeds in your core account, which is the same end state as turning it off by hand.

Which one actually fits your ladder

Laid side by side, the two programs aren’t really competing on the same axis. TreasuryDirect gives you a reversible decision with a real deadline attached — you can watch rates, watch the calendar, and change your mind up until four business days before the next auction, but you take on the job of keeping enough cash on hand to cover a pricier reinvestment, or the roll quietly cancels itself. Fidelity gives you a decision made at purchase that then runs largely unattended until you cancel it, but principal-only rolling means the ladder itself never grows unless you manually redirect the interest it throws off. Neither platform compounds the full return for you; TreasuryDirect’s risk is that a funding gap breaks a roll, and Fidelity’s risk is that idle interest cash quietly caps how much your ladder can grow.

If you’re the type who checks yields before FOMC meetings and might want to redirect a rung on short notice, TreasuryDirect’s editable window rewards that attention. If you’d rather set it up once and only intervene to sweep interest back in every few months, Fidelity’s order-time enrollment removes a recurring task at the cost of that flexibility. Other brokers run similar auto-roll programs with their own eligibility rules and cutoffs, so the general shape — enroll once, principal-only, cancel anytime — tends to repeat even where the specific numbers differ. And if life intervenes and you need to move a TreasuryDirect holding into a brokerage entirely, know going in that a transfer via FS Form 5511 cancels any reinvestment instructions attached to that security the moment it moves — the roll doesn’t follow the bill to its new home. If the real question isn’t rolling at all but getting cash out before maturity, that’s a different problem with its own rules, covered in selling a T-bill before maturity on TreasuryDirect. For the wider context of where T-bills sit against other cash tools, the savings hub is the place to start.

Sources

• TreasuryDirect, “Reinvesting a Treasury Marketable Security”: https://www.treasurydirect.gov/marketable-securities/reinvesting-a-marketable-security/
• TreasuryDirect, “Treasury Bills” (bills sold at a discount or at par): https://www.treasurydirect.gov/marketable-securities/treasury-bills/
• TreasuryDirect, “FAQs about ID.me” (login change on October 28, 2026; scheduled reinvestments): https://www.treasurydirect.gov/savings-bonds/help-center/faqs/idme-faq/
• Fidelity, “Auto Roll Program”: https://www.fidelity.com/fixed-income-bonds/fixed-income-tools-services/auto-roll-program
• Fidelity, “Auto Roll Service Agreement” (cancellation methods, Treasury search window, negative-yield rule): https://www.fidelity.com/bin-public/060_www_fidelity_com/documents/Auto-Roll-Subscriber-Agreement.pdf
• Fidelity, “Auto Roll FAQs” (cancellation deadlines and when the replacement order fills): https://www.fidelity.com/fixed-income-bonds/faqs-auto-roll