Savings I Bonds are a unique, low-risk investment backed by the US Treasury that pay out a variable interest rate linked to inflation. With a holding period from 12 months to 30 years, you could own them as an alternative to bank certificates of deposit (they are liquid after 12 months) or bonds in your portfolio.
New inflation numbers were just announced at
New inflation rate prediction. September 2024 CPI-U was 315.301. May 2025 CPI-U was 319.799, for a semi-annual inflation rate of 1.43%. Using the
Composite rate formula: [Fixed rate + (2 x semiannual inflation rate) + (fixed rate x semiannual inflation rate)]
This results in the variable component of interest rate for the next 6 month cycle being ~2.86 to 2.88%, depending on the fixed rate.
Tips on purchase and redemption. You can’t redeem until after 12 months of ownership, and any redemptions within 5 years incur an interest penalty of the last 3 months of interest. A simple “trick” with I-Bonds is that if you buy at the end of the month, you’ll still get all the interest for the entire month – same as if you bought it in the beginning of the month. It’s best to give yourself a few business days of buffer time. If you miss the cutoff, your effective purchase date will be bumped into the next month. (You should always sell at the very beginning of the month.)
Buying in April 2025. If you buy before the end of April, the fixed rate portion of I-Bonds will be 1.20%. You will be guaranteed a total interest rate of 1.20 + 1.91 = 3.11% for the next 6 months. For the 6 months after that, the total rate will be 1.20 + 2.88 = 4.08%.
Buying in May 2025. If you buy in May 2025, you will get ~2.88% plus a newly-set fixed rate for the first 6 months. The new fixed rate is officially unknown, but is loosely linked to the real yield of short-term TIPS with some reductions. In the previous 10 days, 5-year TIPS real rates have ranged from 1.25% to 1.72%. That’s a nearly 50 basis point swing! If I had to guess, I’d put a new fixed rate somewhere between 1.0 to 1.3%. Every six months after your purchase, your rate will adjust to your fixed rate (set at purchase) plus a variable rate based on inflation.
If you have an existing I-Bond, the rates reset every 6 months depending on your specific purchase month. Everyone will eventually get this variable rate. Your bond rate = your specific fixed rate (based on purchase month, look it up
Buy now or wait? Between those two options, I’m actually not sure. In the short-term, the rates are no better than T-bills. If you are a long-term holder, you might grab the 1.2% fixed rate “bird in the hand”. But the inflation rate will be higher in May by nearly a whole 1%, and so I’d personally just wait and see what happens in mid-October to buy my limit.
Also consider that 30-year TIPS rates on 4/10/25 were at 2.68%! If you really intend to hold for 30 years, that might be a better deal. I plan to fill out my TIPS ladder a bit more if the rates stay this high.
Unique features and considerations. I have a separate post on
The main drawback is hassle. You can only buy new savings bonds through TreasuryDirect.gov, which is limited in its customer service resources and features. But as there is no option for paper tax forms nor statements, so your heirs may never know they exist! If they do find it, it may take them several months to close out all the
Annual purchase limits. The annual purchase limit is
Bottom line. Savings I bonds are a unique, low-risk investment that are linked to inflation and only available to individual investors. You can now only purchase them online at TreasuryDirect.gov. For more background, see the rest of my
[Image: 1942 US Savings Bond poster –