Rates checked 14 November 2026. Series I bonds issued 1 November 2026 to 30 April 2027 pay 5.51 percent. That is the highest headline rate for safe cash in years, and it comes with a rule that decides the whole comparison. You cannot touch the money for 12 months. Not for a car repair, not for a medical bill, not for rent. If your emergency fund goes into I Bonds, it stops being an emergency fund for a full year.
A high yield savings account pays less, 3.20 percent at Ally and 3.75 percent at CIT Bank on balances of 5,000 dollars or more, both checked 14 November 2026. The money stays reachable any day. That is the trade. The rate gap is real, but the lock is what matters, because the job of emergency cash is to be there when you need it, not to earn the most interest.
The numbers, side by side
On 10,000 dollars, with each rate held still for the maths, Ally savings at 3.20 percent pays 320 dollars in a year. CIT Bank Platinum Savings at its standard 3.75 percent on balances of 5,000 dollars or more pays 375 dollars. The FDIC national average savings rate was 0.37 percent in September 2026, which pays 37 dollars on the same 10,000 dollars. An ordinary bank account is not in the same contest.
I Bonds do not fit neatly in that table, and that is the point. The 5.51 percent rate applies for six months only. On 10,000 dollars, the first six months earn 275.50 dollars. The rate for the second six months is not known yet. TreasuryDirect sets a new inflation rate on 1 May 2027, and the composite rate for your bond changes then. So 551 dollars for a full year is not a promise. It is what you would earn only if the second six months paid exactly the same rate, and nobody knows that yet.
CIT Bank also has a promotional rate to read carefully. With promo code BOOST60, CIT adds 0.60 percent for six months, which takes the rate on balances of 5,000 dollars or more to 4.35 percent. The promotion ends 15 December 2026, and the account then falls back to the standard rates.
What the 5.51% really means
An I Bond rate has two parts. The fixed rate stays with your bond for its whole life, up to 30 years. The inflation rate resets every six months. For bonds issued 1 November 2026 to 30 April 2027, TreasuryDirect lists a fixed rate of 1.40 percent and a semiannual inflation rate of 2.04 percent. The formula combines them into a composite rate of 5.51 percent. TreasuryDirect shows the arithmetic on its own page: 0.0140 plus twice 0.0204 plus the small cross term gives 0.0550856, rounded to 5.51 percent.
The 1.40 percent fixed rate is the part worth noticing. It matches the 1.40 percent fixed rate last set in 2006, and it is up from 0.90 percent for bonds issued in the previous two six month windows. That fixed rate stays with the bond for as long as you hold it, while the inflation part moves. If inflation falls, the composite rate falls with it, and it can fall as low as zero. Interest compounds semiannually, so every six months the interest earned is added to the bond value.
That is why the headline is both true and misleading. The 5.51 percent is real for six months. The 1.40 percent is real for the life of the bond. Nothing else about the rate is locked in.
The lock is the decision
TreasuryDirect states the rules plainly. You can cash in an I Bond after 12 months. If you cash it in before five years, you lose the last three months of interest. Cash it in after 18 months and you keep the first 15 months of interest. After five years, there is no penalty.
Put that next to a real emergency. Your car needs a 900 dollar repair in month eight. If that 900 dollars is in a savings account, you pay the bill. If it is in I Bonds, you cannot reach it at all, and the repair goes on a credit card. The bond did not fail. It was the wrong home for that money.
The purchase limit adds a second constraint. You can buy up to 10,000 dollars in electronic I Bonds per person per calendar year, counted by Social Security number, with a 25 dollar minimum. A 20,000 dollar emergency fund would take two calendar years to move into I Bonds.
What savings really pays
A high yield savings account is a bank deposit, not a bond. Your money stays reachable, the rate is variable, and the account is insured by the FDIC up to 250,000 dollars per depositor, per bank, per ownership category. Ally lists 3.20 percent APY on its savings account on all balance tiers, with no minimum opening deposit. Ally states the figure was correct as of 12 November 2026.
CIT Bank Platinum Savings is tiered, and the tier is a cliff, not a slope. On balances of 5,000 dollars or more, the standard rate is 3.75 percent APY. On balances below 5,000 dollars, it is 0.25 percent APY. CIT states those APYs were accurate as of 1 July 2026, and that rates are variable and may change at any time. The minimum to open the account is 100 dollars. A balance of 4,999 dollars at 0.25 percent earns about 12.50 dollars in a year. A balance of 5,000 dollars at 3.75 percent earns 187.50 dollars. Check your balance against the tier before you open the account, not after.
Which pile goes where
Sort your cash by when you will need it, not by which rate looks biggest. Money you might need in the next year stays in high yield savings. That is your emergency fund, your rent buffer, and any cash for a move, a repair, or a bill due in the next 12 months. The 12 month lock rules out I Bonds for all of it.
Money you will not touch for at least a year, and ideally for five years, is the only pile that belongs in I Bonds. That is spare cash above your emergency fund, or money saved for a goal more than a year away. Buy it in the November 2026 to April 2027 window if you want the 1.40 percent fixed rate, and only up to the 10,000 dollar annual limit.
Money for a goal more than five years away has a third option. A broad low cost index fund has historically earned more over long periods, with real risk attached. That path is here: How to Start Investing With $100: Index Funds for Beginners. Do not put money you need in five months into I Bonds. The timeline decides, every time.
If you are still carrying card debt at about 22 percent APR, neither account is your first move. Paying down that debt earns a return equal to the interest you stop paying, which beats both rates here. The maths behind that order is here: Average Credit Card APR 2026.
Tax, in three lines
I Bond interest is subject to federal income tax, and exempt from state and local income tax. You can choose to report the interest each year, or wait and report it all when you cash the bond or it matures. If you use the proceeds for qualified higher education expenses, some or all of the interest may be excluded from federal tax, under strict rules including an age condition and income limits, so check IRS Form 8815 before you count on it. Savings account interest is taxed as ordinary income in the year you earn it, at federal and state level.
The bottom line
I Bonds win on rate right now, 5.51 percent for six months against 3.20 to 3.75 percent from savings. Savings wins on access, and access is the job. Keep your emergency fund in high yield savings, where you can reach it tomorrow. Use I Bonds only for money you are sure you will not need for at least a year, and only up to 10,000 dollars a year. For the full payoff journey, and for why the order of your money matters more than the rate on any one account, UNOWED: The Step-by-Step Beginner’s Guide to Getting Out of Debt and Staying Out, it covers it in eight chapters.
If you are in the UK, I Bonds are a US Treasury product and you cannot buy them. The question still applies to your own savings: a fixed rate account that locks your money is not an emergency fund, whatever rate it pays.
This article is general information only, not personal financial advice. Rates are variable, I Bond rates reset every six months, and your tax position will differ, so check TreasuryDirect and your bank before you move money.
Rates last checked 14 November 2026.
Sources
- TreasuryDirect, I bonds interest rates, read 14 November 2026: composite rate 5.51 percent for I bonds issued 1 November 2026 to 30 April 2027, fixed rate 1.40 percent, semiannual inflation rate 2.04 percent, formula 0.0140 plus twice 0.0204 plus the cross term giving 0.0550856, rounded to 5.51 percent. Fixed rate table shows 1.40 percent on 1 November 2006 and 1 May 2006, and 0.90 percent on 1 May 2026 and 1 November 2025. Composite rate changes every six months, cannot go below zero, interest compounds semiannually.
- TreasuryDirect, I bonds at a glance, read 14 November 2026: cash in after 12 months, lose the last three months of interest if cashed in before five years, example cashing in after 18 months keeps the first 15 months of interest. Federal income tax yes, state and local income tax no, choice to report each year or wait until redemption, possible exclusion for qualified higher education expenses. Minimum 25 dollars, maximum 10,000 dollars in electronic I bonds per calendar year per Social Security number or Employer Identification Number. Interest earns for up to 30 years.
- Ally Bank, rates page, read 14 November 2026: savings APY 3.20 percent, correct as of 12 November 2026, rate variable and may change after the account is opened, no minimum opening deposit, limit of 10 withdrawals per statement cycle, fees may reduce earnings.
- CIT Bank, Platinum Savings boost page, read 14 November 2026: standard rates 3.75 percent APY on balances of 5,000 dollars or more and 0.25 percent APY below 5,000 dollars, APYs accurate as of 1 July 2026, rates variable and may change at any time, minimum to open 100 dollars, FDIC insured up to 250,000 dollars per depositor per ownership category. Boost promotion with code BOOST60 adds 0.60 percent APY for six months, giving 4.35 percent on balances of 5,000 dollars or more and 0.85 percent below, promotion ends 15 December 2026.
- FDIC National Rates and Rate Caps, September 2026, national average savings rate 0.37 percent APY, as reported in October 2026 rate roundups. This figure was not read on the FDIC page itself.
- Pexels, photo 9821387, Towfiqu barbhuiya, https://www.pexels.com/photo/9821387/, free license. File checked visually on 14 November 2026, no legible brand logo.
