I Bonds or TIPS: Which Inflation Hedge Wins in 2026?

The 60-second rule

If you’re parking $10,000 or less and can leave it 5+ years, buy I Bonds. The 0.90% fixed rate is locked for the bond’s life, the 4.26% composite beats every savings account, tax deferral compounds for decades, and the principal can never fall. If you need more than $10,000 of inflation protection — or you have IRA room — buy TIPS. The cap, not the math, is what pushes most big portfolios into TIPS. And the tiebreaker: compare the I Bond’s fixed rate to the TIPS real yield you can actually buy. At the worked example the break-even real yield is 0.97% — above it, TIPS win; below it, I Bonds win. One number, checked once, decides the whole fight.

How I Bonds work: the 4.26% number, decoded

An I Bond is two rates welded together. The fixed rate — 0.90% for bonds bought May through October 2026 — is set when you buy and never changes. It is your guaranteed real return for up to 30 years: whatever inflation does, you earn 0.90% above it. The inflation rate — 3.34% annualized right now — resets every six months for every I Bond ever issued, tracking the CPI. Welded together they make the 4.26% composite, announced by TreasuryDirect on May 1, 2026 (up from 4.03%), resetting again November 1. Interest accrues monthly, compounds semiannually, and the composite can never go below zero — in deflation, you simply earn the fixed rate on a flat principal. Your money cannot shrink. That floor is the I Bond’s quiet superpower, and it’s why 2022’s 9.62% print crashed the TreasuryDirect website: risk-free, inflation-linked, can’t-go-down.

Then the guardrails. You can buy $10,000 per person per calendar year electronically through TreasuryDirect — redeeming doesn’t restore the limit — plus $5,000 in paper bonds by directing your federal tax refund on IRS Form 8888. A married couple can each buy $10,000. You cannot touch the money for 12 months, and cashing out before 5 years forfeits the last 3 months of interest. The bond earns interest for up to 30 years. Taxes: federal only — no state or local income tax — and you can defer the federal tax until you redeem, which is where the long-horizon magic comes from. (Parents: I Bond interest can be federally tax-free for college, but the income limits and registration rules are strict — check them before you count on it.)

How TIPS work: the machinery nobody explains

Treasury Inflation-Protected Securities take the opposite approach: instead of a floating rate, they float your principal. Buy $10,000 of TIPS, inflation runs 3%, and your principal becomes $10,300 — the fixed coupon then pays on the bigger number. You buy at Treasury auction or on the secondary market, quoted in real yields: the return above inflation, locked at purchase if — and only if — you hold to maturity. Maturities run 5, 10, and 30 years. Two catches the brochure undersells. First, price risk. Sell before maturity and you get the market price, which falls when real yields rise — TIPS can lose money; I Bonds cannot. Second, phantom income. The IRS taxes the inflation adjustment to your principal every year, even though you don’t receive that money until maturity. You pay real tax on unrealized gains, and you need cash from somewhere else to do it. Like I Bonds, TIPS are exempt from state and local tax. The advantages: no purchase limit — buy $10,000 or $10 million — and, decisively, TIPS can live inside an IRA, where the phantom-income problem vanishes. I Bonds cannot be bought in an IRA at all.

Both bonds’ math, side by side

Same $10,000, same 5 years, same 2.5% inflation, same 22% bracket — the only differences are the rates and the tax timing:

• The I Bond path: semiannual composite = (1 + 0.90%/2) × (1 + 2.5%/2) − 1 = 1.7056% per half-year → 3.44% effective a year. $10,000 compounds to $11,842 in 5 years (redeemed at exactly 5 — no penalty). Tax deferred the whole way, then $1,842 of gain × 22% = $405 → $11,437 after tax. The full balance compounded; the tax waited.
• The TIPS path: nominal return = (1 + 0.50%) × (1 + 2.5%) − 1 = 3.01% a year — but taxed every year on interest plus the inflation adjustment: 3.01% × 78% = 2.35% after tax → $11,231 after tax. The phantom-income tax is an annual leak the I Bond never springs.

The gap — $206 to I Bonds — came from two things: the I Bond’s 0.90% fixed rate beat the TIPS’s 0.50% real yield, and deferring the tax let the full balance compound. Neither advantage is permanent; both are checkable.

The worked example, line by line

• Year 0: $10,000 goes in. The I Bond locks a 0.90% real rate for life; the TIPS locks a 0.50% real yield to maturity. Both are federal-tax-only. The race is on.
• Years 1–5: at 2.5% inflation, the I Bond’s composite runs about 3.44% effective a year; the TIPS’s nominal runs 3.01%. But the TIPS pays tax annually — 2.35% after tax — while the I Bond’s $1,842 of gain sits untaxed. Deferral is invisible and relentless.
• Year 5: $11,437 vs $11,231 — I Bonds by $206. The penalty question is moot at exactly 5 years; at 3 years the 3-month forfeiture would have shrunk the gap to a $39 near-tie.
• The sensitivity: TIPS real yield at 1.8% (a plausible market print) → TIPS win by $376. Inflation at 5% → I Bonds win by $295 (both scale up, deferral compounds harder). Hold 30 years → I Bonds win by $3,645: decades of untaxed compounding are the I Bond’s superpower — the annual TIPS tax drag, repeated 30 times, is a slow bleed.
• The break-even: at these settings, TIPS need a real yield of 0.97% to tie the I Bond. That’s the only number you need to check before buying: if the 5- or 10-year TIPS real yield is above it, buy TIPS; below it, buy I Bonds.

The $10,000 cap trap

This is the paragraph that decides more real cases than all the math above. I Bonds are the better bond per dollar for most savers — but only for the first $10,000 a year per person. A couple gets $20,000; the tax-refund paper trick adds $5,000; the gift box lets you buy today and deliver in future years. And then you hit the wall. Need $100,000 of inflation protection? The first $10k goes to I Bonds, and the other $90k has nowhere to go but TIPS — at whatever real yield the market offers. High earners with big bond allocations don’t choose I Bonds over TIPS; they choose I Bonds and TIPS, in that order, every January. The cap also means I Bonds can’t be a portfolio’s core holding — they’re a satellite by law. Treat the $10,000 as a yearly coupon you should clip, not as an asset allocation.

The IRA question (it settles a lot of fights)

TIPS can be bought inside an IRA or 401(k); I Bonds cannot. That single rule reorganizes the whole comparison for retirement savers. Inside a traditional IRA, TIPS’ phantom-income tax disappears — the annual leak that cost them $206 in our example simply doesn’t exist — which flips close calls toward TIPS. Outside tax-advantaged accounts, the I Bond’s deferral is the closest taxable investors get to the same effect. The practical setup for a serious inflation hedge: max the I Bonds in taxable every year ($10k/person), hold TIPS inside the IRA. Each bond goes where its tax treatment is kindest, and you stop arguing about which is "better" in the abstract.

Three questions to ask before you buy

• 1. "What’s the TIPS real yield right now — and is it above 0.97%?" Check the 5- or 10-year TIPS real yield against the break-even from the comparison (recalculate with your inflation assumption and bracket). Above the line: TIPS. Below it: I Bonds. This one check beats every forum argument.
• 2. "How much do I need to protect — and does it fit in $10,000?" If the answer is $10k or less and you can hold 5+ years, the I Bond decision is nearly automatic. If it’s $50k, the first $10k is automatic and the rest is a TIPS decision at market yields.
• 3. "Where will it live — taxable or IRA?" TIPS in an IRA dodge the phantom-income tax entirely; I Bonds can’t enter an IRA at all. If your inflation hedge has to live in a taxable account and you’re under the cap, the I Bond’s deferral is doing real work for you.

Three mistakes

• Mistake 1: Buying I Bonds for money you’ll need in year one. The 12-month lockup is absolute — no hardship exceptions, no early exit. I Bonds are for the deep reserve, not the first-responder fund. Money you might need in 11 months belongs in a no-penalty CD or savings account, not TreasuryDirect.
• Mistake 2: Treating the 4.26% as a promise. It’s a six-month composite, not a yield to maturity — the inflation half resets every May and November, and in a low-inflation stretch your composite can fall toward the fixed rate. Price the bond on the 0.90% fixed rate (the permanent part), not the 4.26% (the weather).
• Mistake 3: Holding TIPS in taxable when IRA room exists. Every year of phantom-income tax is a leak you chose. If you have unused IRA or 401(k) space and you’re buying TIPS in a taxable account anyway, you’re paying a tax you didn’t have to pay.

Run your own numbers — your amount, your horizon, the real yield you can actually buy — in the I bonds vs TIPS comparison.