The statutory ceiling
This rate is set by statute rather than bid down at the sale, so every certificate sold carries it. Competition happens on price instead. There is no statutory minimum return.
No minimum rate
Iowa sets no statutory minimum return. Because the rate is not bid down, competition shows up in the share of ownership taken instead, which is what erodes your yield.
How interest accrues
The statutory rate is 2 percent per month, which annualizes to 24 percent. Interest runs from the month of sale on the amount the parcel sold for including the certificate fee, and from the month of payment on any subsequent-year taxes the holder pays. Each fraction of a month counts as an entire month, so a redemption early in a month still costs a full month of interest and the effective annualized return on a short hold can exceed 24 percent. The interest amount is rounded to the nearest whole dollar and must be at least one dollar. Because the rate is fixed by statute and never bid, there is no rate below 24 percent per year.
What bidders actually bid down
Iowa bidders do not bid the interest rate down. They bid down the percentage of undivided ownership in the parcel they will accept if a treasurer's deed later issues, and the smallest percentage offered wins. The percentage cannot be less than 1 percent, so a competitive parcel typically sells at a 1 percent bid. When two or more bidders offer the same smallest percentage, the treasurer picks the winner by a random selection process. A parcel offered at a public nuisance tax sale under section 446.19B cannot be bid below 100 percent.
When the certificates sell
Annually on the third Monday in June, when the county treasurer offers every parcel with delinquent taxes at public sale. For good cause the treasurer may designate a different date in June, and a parcel that cannot be advertised and offered in June is sold on the third Monday of the next month in which notice can be given. The treasurer mails notice of the sale by May 1 and publishes it once, at least one week and not more than three weeks before the sale.
The headline figure is a ceiling, not a forecast. To see what a certificate actually pays over a real holding period, run the numbers in the yield calculator, and compare Iowa against other states on interest rates by state.
Verified Jul 29, 2026 against Iowa statutes.
Tax Sale Atlas publishes educational information about public tax sale processes. This is not legal, financial, or investment advice. Rules, dates, and fees change; confirm with the county office before you bid.