Series I Savings Bonds issued from May 1, 2026 through October 31, 2026 earn a 4.26% composite rate for their first six months. That rate is the result of two pieces: a fixed rate that stays with the bond for its life and an inflation component that changes every six months.
The May 2026 I Bond rate is useful for savers who want inflation-linked, U.S. government-backed savings, but it is not the same as a savings account, Treasury bill, CD, or money market fund. I Bonds have purchase limits and redemption restrictions that make them best for money you can leave alone for at least one year.
If you are comparing cash options, read Treasury Bills vs CDs vs High-Yield Savings in 2026. If you already own older I Bonds, see When Can I Cash Out I Bonds?.
The May 2026 I Bond Rate
The announced composite rate for new I Bonds bought from May through October 2026 is 4.26%.
That composite rate includes:
- a 0.90% fixed rate
- a semiannual inflation adjustment that applies for a six-month earning period
The fixed rate matters because it stays attached to the bond for up to 30 years. The inflation rate changes every six months based on CPI-U inflation data.
What the Composite Rate Means
The composite rate is annualized. It does not mean you receive 4.26% immediately. I Bonds earn interest monthly and compound semiannually.
Example: If you buy an I Bond in May 2026, the 4.26% composite rate applies for the first six months. After that, your bond receives the next composite rate, using the same fixed rate attached to your bond plus the then-current inflation component.
I Bond rates reset on this schedule:
| Purchase month | First rate period |
|---|---|
| May 2026 | May through October 2026 |
| June 2026 | June through November 2026 |
| July 2026 | July through December 2026 |
| August 2026 | August 2026 through January 2027 |
| September 2026 | September 2026 through February 2027 |
| October 2026 | October 2026 through March 2027 |
The rate reset is based on your purchase month, not only the Treasury’s May and November announcement dates.
I Bonds Are Not Fully Liquid
The most important drawback is liquidity.
I Bond redemption rules:
- You cannot cash out in the first 12 months.
- If you redeem before five years, you forfeit the last three months of interest.
- After five years, there is no three-month interest penalty.
- Bonds can earn interest for up to 30 years.
That makes I Bonds a poor fit for money you may need next month. They can be useful for a secondary emergency reserve, future tax bill, inflation hedge, or medium-term savings bucket, but only after the one-year lockup is acceptable.
Purchase Limits
Most individuals can buy up to $10,000 in electronic I Bonds per calendar year through TreasuryDirect. In addition, taxpayers may be able to buy paper I Bonds using a federal tax refund, subject to separate limits and IRS/Treasury rules.
The electronic limit is per person, not per bank account. Married couples may each buy their own annual limit if each has a TreasuryDirect account. Trusts and certain entities can have their own rules, but buyers should not create entities just to buy savings bonds without understanding legal and tax consequences.
I Bonds vs Treasury Bills
I Bonds and Treasury bills are both backed by the U.S. government, but they behave differently.
| Feature | I Bonds | Treasury bills |
|---|---|---|
| Rate type | Inflation-linked composite rate | Market auction discount rate |
| Liquidity | Locked for 12 months | Maturities from 4 weeks to 52 weeks |
| Early sale | Redeem through TreasuryDirect after lockup | Can hold to maturity or sell in brokerage account |
| Purchase limit | Annual limit | Much higher practical limits |
| State tax | Exempt from state and local income tax | Exempt from state and local income tax |
| Federal tax | Can defer until redemption/maturity | Taxable federally in year interest is recognized |
If you need known maturity dates, T-bills may be easier. If you want CPI-linked savings and can accept the lockup, I Bonds may be attractive.
Tax Treatment
I Bond interest is subject to federal income tax but generally exempt from state and local income tax. Many investors defer federal tax until the bond is redeemed or matures, although annual reporting can be elected.
There is also an education-related exclusion for eligible taxpayers who use savings bond interest for qualified higher education expenses, but income limits and ownership rules apply. Do not assume the exclusion applies without checking the IRS rules for the year of redemption.
Should You Buy in May-October 2026?
The 4.26% composite rate is most attractive if:
- you already have liquid emergency savings
- you can leave the money untouched for at least 12 months
- you value inflation protection
- you live in a state with income tax
- you want direct U.S. government backing
- you do not need a high annual purchase limit
It may be less attractive if:
- you might need the cash within a year
- you can get a better risk-free yield from T-bills or CDs
- you dislike TreasuryDirect account management
- you need monthly income
- you are trying to invest for long-term growth
Bottom Line
The May 2026 I Bond composite rate is 4.26%, with a 0.90% fixed rate for new bonds issued from May through October 2026. The fixed rate is the long-term prize; the inflation component will change. I Bonds are most useful for inflation-linked savings that can tolerate a one-year lockup.
Related Reading
- I Bond Fixed Rate 0.90%: Why It Matters
- When Can I Cash Out I Bonds?
- TIPS vs I Bonds vs EE Bonds in 2026
- Treasury Bills vs CDs vs High-Yield Savings in 2026
Sources
- TreasuryDirect, May 2026 savings bond rate announcement: https://www.treasurydirect.gov/news/2026/release-05-01-rates/
- TreasuryDirect, Series I Savings Bonds: https://www.treasurydirect.gov/savings-bonds/i-bonds/
- IRS Publication 550, investment income and expenses: https://www.irs.gov/publications/p550