Anyone who read this site’s May 2026 I Bond post knows the punchline going in: the fixed rate held at 0.90%, the whole decision came down to guessing six months of inflation, and the stakes were something like $15-30 on a $10,000 purchase. Boring, in the good way.

November is not that. TIPSWatch’s Aug. 9 analysis says the fixed rate Treasury sets on Nov. 1 “looks like a real possibility” of landing at 1.30% — up from the 0.90% that’s applied to every I bond sold since November 2025. That’s not a rounding blip. It would be the first increase to this number in two years, after three straight resets that took it from 1.20% to 1.10% to 0.90%. And unlike the variable rate, which resets every six months no matter what you do, the fixed rate you lock in at purchase stays with your bond for up to 30 years.

That’s the actual question this post answers: is a projected 40-basis-point fixed-rate bump worth waiting roughly ten weeks for, or should you just buy now and take what’s on the table?

Quick Verdict: I Bonds Before or After Nov. 1, 2026

Question	Answer
Current composite rate (bought through Oct. 31)	4.26% — 0.90% fixed + 3.34% inflation component
TIPSWatch’s projected new fixed rate	~1.20-1.30%, based on 5-year TIPS real yields
Projected new inflation component	3.0%-4.0% annualized (March-Sept. 2026 CPI-U)
Implied new composite range	Roughly 3.9%-4.9%
Is the fixed rate locked for life?	Yes — up to 30 years, whatever rate applies the day you buy
Competing HYSA/CD rates right now	Roughly 4.00%-4.50% APY
Annual purchase limit	$10,000 electronic + up to $5,000 paper via tax refund
Should you wait for Nov. 1?	If you can stomach ~10 weeks of cash sitting in a HYSA, probably yes

Why This Reset Isn’t Like May’s

The May 2026 reset was a non-event on the fixed-rate side because TIPSWatch’s own pre-reset projection called for the fixed rate to hold — and it did, exactly at 0.90%. The only open variable was the CPI-driven inflation component, and since both outcomes used the same 0.90% fixed rate, the entire decision came down to a few weeks of interest on money that was going to be roughly the same either way.

Fixed rates don’t move like that most cycles. Since November 2024 the sequence has been 1.20%, then 1.10%, then 0.90% — three consecutive step-downs as 5-year TIPS real yields compressed. TIPSWatch’s Aug. 9 read is that the trend just reversed, and reversed by more than a token amount. If it holds, November would be the first up move since the fixed rate sat at 1.30% back in late 2023 — and it’s the reason this reset actually deserves the “should I wait” question, instead of the shrug that was the right answer in April.

How the Fixed Rate Actually Gets Set

There’s no published formula. Treasury has full discretion, and the fixed rate decision has surprised forecasters before. But TIPSWatch has tracked a pattern that’s held up for roughly a decade: apply a ratio of about 0.65 to the six-month average real yield on 5-year TIPS, and you get a workable estimate of where the new fixed rate lands.

1. The six-month average 5-year real yield, as of Aug. 8, was about 1.84%. Multiply that by 0.65 and you get 1.196% — which rounds to 1.20%, since Treasury sets the fixed rate to the nearest tenth of a point.
2. The single-day 5-year real yield on Aug. 8-9 had already climbed to 2.13% — noticeably above the six-month average, which means the average itself is still trending up heading into the Oct. 31 lock date.
3. The rounding threshold for 1.30% is a ratio result of 1.251% or higher. With roughly 57 market days left as of the Aug. 9 article and real yields still climbing, that threshold isn’t a stretch — it’s close enough that a few more weeks of elevated yields gets you there.

None of that is a guarantee. It’s a well-tested estimate built off market data that can still move between now and the last trading days of October. But “somewhere between 1.20% and 1.30%” is a meaningfully different starting point than “hold at 0.90%,” which is what made the May call easy.

What the Inflation Side Looks Like

The fixed rate isn’t the whole story — the variable component still does most of the heavy lifting on your actual return. November’s rate is built off CPI-U data from March through September 2026, with the September number landing in mid-October, right before Treasury’s announcement.

Current projections put that annualized inflation component in the 3.0%-4.0% range, which isn’t wildly different from the 3.34% baked into the current 4.26% composite. Combine both pieces and you get a rough composite range of 3.9% to 4.9% for I bonds bought Nov. 1 or later — a wider band than usual, because the fixed-rate piece is genuinely uncertain this cycle in a way it usually isn’t.

How I Bonds Actually Work (Quick Refresher)

An I bond’s composite rate combines two pieces: a fixed rate that’s set at purchase and locked for the life of the bond (up to 30 years), and a variable rate that resets every six months based on CPI-U inflation. The fixed rate is the part that matters for long-term holders, since it’s the only piece you actually get to choose. The variable piece adjusts with inflation no matter when you bought, so it evens out over time regardless of your purchase date.

That’s the mechanic that makes this reset different from May’s. Buy in September and your 0.90% fixed rate is locked forever, even though your variable component will keep resetting with everyone else’s every six months. Wait until Nov. 1 and, if TIPSWatch is right, you lock a fixed rate as much as 0.40 points higher — permanently, on whatever you put in that day.

The Actual Math: Is Waiting Worth It?

Two separate questions get bundled into “should I buy now,” and they deserve separate answers.

Question one: what does waiting cost you in the short term? From late August to Nov. 1 is roughly ten weeks. Park that money in a high-yield savings account or short CD at 4.00%-4.50% instead, and you’re not giving up much — that’s close enough to the current 4.26% I bond composite that the difference over ten weeks is single-digit dollars on a $10,000 purchase, not a meaningful sacrifice.

Question two: what’s a higher fixed rate actually worth over decades? This is where it gets interesting, and where the case for waiting gets real teeth.

Run a back-of-envelope version: $10,000 compounding semiannually at a 0.90% fixed rate for 30 years grows the fixed-rate portion of your balance by roughly 31% in real terms. The same $10,000 at 1.30% grows by roughly 48%. The difference — about $1,650 in additional real, inflation-adjusted growth over 30 years — comes purely from the higher locked-in fixed rate, before counting a single dollar of whatever inflation adjustments show up along the way, since those apply equally to both scenarios. That’s a rough illustration, not a guaranteed return, and it assumes you actually hold the bond three decades, which most people don’t.

Which is the honest caveat here: this math only pays off in full if you’re the kind of buyer who treats I bonds as multi-decade savings, not an emergency-fund parking spot you’ll cash out in year two. If you’re holding past the required 5-year mark to dodge the early-withdrawal penalty anyway, a permanently higher fixed rate compounds in your favor every year you keep holding. If you’re likely to redeem in year 3 or 4, the fixed-rate gap barely has time to matter and the ten-week wait is closer to free money for no real tradeoff.

I Bonds vs. CDs and HYSAs Right Now

Vehicle	Current Rate	Locked How Long	Inflation Protection
I bonds (bought by Oct. 31)	4.26% composite (0.90% fixed)	Fixed rate locked up to 30 years; variable resets every 6 months	Yes — variable component tracks CPI
I bonds (bought Nov. 1+, projected)	~3.9-4.9% composite (~1.20-1.30% fixed)	Same structure, higher fixed floor	Yes
CD ladder	~4.00-4.50% APY	Fixed for CD term (months to years)	No
High-yield savings	~4.00-4.50% APY	Not locked, rate floats	No

The CD and HYSA numbers aren’t guaranteed to hold either — this site has covered how fast Fed-odds-driven rate moves can swing CD pricing this same month. But they’re liquid or short-term, where an I bond’s fixed rate is a 30-year commitment on whatever number you lock. That asymmetry is exactly why the projected fixed-rate jump matters more than it would for a CD comparison alone.

Should You Buy I Bonds Before November 2026?

If you haven’t touched your 2026 allocation yet, waiting is the stronger play this cycle — specifically because this reset is structurally different from May’s. Here’s the decision framework:

1. Do you have unused 2026 I bond allocation ($10,000 electronic, plus $5,000 paper via tax refund)? If not, this question is moot until January.
2. Can you park the money in a HYSA or short CD for roughly ten weeks without meaningfully sacrificing yield? At today’s 4.00%-4.50% rates, yes for most people.
3. Do you expect to hold the bond past the 5-year early-withdrawal penalty window, ideally much longer? If yes, a higher locked-in fixed rate compounds in your favor for as long as you hold it. If you’re likely to redeem in 2-3 years, the fixed-rate gap won’t have time to add up to much.
4. Are you comfortable that TIPSWatch’s projection is an estimate, not a guarantee? Treasury could land at 1.20% instead of 1.30%, or in a rate-cut scenario could even hold flat. The 5-year TIPS yield still has roughly two months to move before the Oct. 31 cutoff.

If your answers land on “yes, yes, yes, yes” — wait. The downside of waiting is small and the upside, for a long-term holder, is a fixed-rate advantage you carry for as long as you own the bond. If you’re using I bonds as a short-hold parking spot instead of a decades-long allocation, the fixed rate barely matters to your outcome either way, and there’s no real reason to wait — buy whenever it’s convenient.

What Could Change Between Now and Nov. 1

The projection isn’t locked. A few things could move it:

• 5-year TIPS real yields could retreat. They’ve climbed sharply since spring, but Treasury auctions between now and late October could pull that average back down toward the 1.20% end of the range instead of 1.30%.
• September CPI-U could come in hotter or cooler than expected, shifting the inflation-component side of the equation independent of the fixed rate.
• Treasury retains full discretion. The 0.65 ratio is a pattern, not a rule. It’s worked for roughly a decade, but Treasury isn’t bound to it, and the actual Nov. 1 announcement is the only number that counts.

The Bottom Line

May’s reset didn’t matter much because the fixed rate was never in question — the whole decision was a rounding error dressed up as a choice. November is a genuinely different setup: a fixed rate that’s fallen three resets in a row is projected to jump by as much as 0.40 points, on a piece of the bond that locks for up to 30 years once you buy.

The cost of waiting is close to nothing — ten weeks parked in a HYSA paying nearly the same rate as the I bond you’d otherwise buy today. The upside, if you’re a long-term holder and TIPSWatch’s projection holds, is a permanently better rate on money you’re not planning to touch for decades. That’s a rare setup where patience is close to free. Unless you’re certain you’ll redeem well before the 5-year mark, or you’re buying purely for this year’s inflation number and don’t care about the fixed-rate floor, there’s little reason to lock in 0.90% two months before Treasury might hand you something meaningfully better.

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Current I bond rate (4.26% composite, 0.90% fixed) confirmed by TreasuryDirect’s May 1, 2026 rate announcement. November 2026 fixed-rate projection, the 0.65 real-yield ratio methodology, and 5-year TIPS real yield data from TIPSWatch’s Aug. 9, 2026 analysis. Fixed rate history (1.20% Nov. 2024, 1.10% May 2025, 0.90% Nov. 2025) per TIPSWatch’s rate-tracking archive. Mechanics of composite-rate calculation per TreasuryDirect’s I bond interest rates page. The 30-year compounding example is an illustrative estimate, not a guaranteed return. This is not financial or tax advice — verify current rates at TreasuryDirect.gov before purchasing, and consult a professional for your specific situation.