EDO or COI? Which Polish treasury bonds to choose

Of TOS, COI and EDO in the October 2026 offer, at 4.1% inflation, EDO pays the most if you can leave the money for at least 2 years. After 10 years, PLN 10,000 grows to PLN 16,440 after tax with EDO, PLN 14,191 with COI and PLN 14,141 with TOS. After 4 years — when COI matures — EDO pays only a little more than COI: PLN 11,849 against PLN 11,747, although EDO has to be redeemed early, with a fee. But COI pays out PLN 1,293 of interest along the way, which we don't reinvest here; if that interest were reinvested in a 12-month deposit paying a rate equal to today's NBP reference rate (3.75% before tax), we estimate COI would reach about PLN 11,825 — still a little less than EDO.

How do EDO, COI and TOS differ?

All three are retail savings bonds (obligacje oszczędnościowe) issued by the Polish State Treasury. They cost PLN 100 each, and a new series goes on sale every month. They differ in term, in how the rate is set and in what happens to the interest. This is how they look in the October 2026 offer:

TOS (3-year) have a fixed rate for the whole term, so you know the result on the day you buy. COI (4-year) and EDO (10-year) are inflation-linked: they pay a fixed rate in year 1 and inflation plus a margin from year 2. The margin is a fixed premium over inflation, set for the series for its whole term. The inflation used comes from Statistics Poland (GUS): in the words of the offer (our translation), it is “the rate of growth in the prices of consumer goods and services, taken for 12 months and announced by the President of Statistics Poland in the month preceding the first month of the given interest period”. When inflation is negative, zero is used instead, so the rate never drops below the margin.

EDO and TOS add the interest to the bond's value every year and pay it out only at maturity. COI pays the interest out after each year and starts the next year from PLN 100 again.

Families who receive the 800+ child benefit can also buy the family bonds: 6-year ROS with a 2.00% margin and 12-year ROD with a 2.50% margin (EDO: 2.00%), up to the amount of the 800+ benefit granted. In the scenario below, after 10 years ROD would give PLN 16,861, against PLN 16,440 from EDO.

Which bond pays the most at today's inflation?

We used the bonds calculator to work out what you get from PLN 10,000 after the Belka tax (podatek Belki, Poland's 19% tax on interest) and fees if you stop saving after 1, 2, 3, 4, 6 or 10 years. Inflation stays at 4.1% throughout — the latest GUS figure (for September 2026).

Going year by year from 1 to 10, at 4.1% inflation the best bond is TOS for 1 year and EDO for 2–10 years. Over a year or two, each of the three bonds compared has to be redeemed early, so the first-year rate and the early redemption fee weigh heavily. The longer you keep the money, the more the margin and the yearly compounding matter. For shorter horizons the offer also has 1-year ROR and 2-year DOR bonds (and 3-month OTS), which we don't compare here.

Allowing for 4.1% inflation a year, the PLN 16,440 from EDO after 10 years is worth about PLN 11,000 in today's money — PLN 1,000 more than you put in, in real terms.

EDO or COI — what decides the result?

In the October 2026 offer EDO has a higher first-year rate than COI (5.35% against 4.75%) and a higher margin (2.00% against 1.50%).

EDO also has two advantages that come from how it works, whatever the rates. The first is compounding: interest added to the bond earns interest itself the following year. The second is deferred tax: on EDO you pay it once, at maturity, so for years the money that will eventually go to the tax office keeps earning too. COI pays out its interest every year with the tax already taken off.

In the 10-year scenario COI pays you PLN 3,879 of interest after tax along the way. The calculator counts it as cash that earns nothing more. If you invest the interest you receive every year, in more bonds for example, COI's result will be higher than in the table — by whatever that money earns, which depends on where you put it and at what rate.

So when does COI make sense? When you want interest paid into your account every year, for example to top up a pension or cover regular spending. The shorter term can also be an advantage: after 4 years the money comes back to you without a fee and you can invest it on the terms of the offer at that time. Our guide to the Belka tax explains how the tax on interest affects the result.

What if inflation turns out different?

Nobody knows what inflation will be over the next 4 or 10 years, so we ran the same scenario at 1%, 2.5%, 5% and 8% inflation. The 2.5% rate is the National Bank of Poland's (NBP) inflation target, with a tolerance of 1 percentage point either way. The table shows the best bond and its average yearly return after tax and fees.

Over 4 years the best bond is TOS at 1% and 2.5% inflation, and EDO at 5% and 8%. Over 10 years the best bond is TOS at 1% inflation, and EDO at 2.5%, 5% and 8%.

TOS's result doesn't depend on inflation at all, so its fixed rate is in effect a bet that inflation stays low. Over 10 years EDO pays more than TOS when inflation stays at about 2.1% or more the whole time; over 4 years, at about 2.7% or more. Over horizons longer than 3 years, further TOS series are bought on today's terms, and nobody knows what rate TOS will pay in 3 or 6 years' time.

At 8% inflation the best bond over 10 years, EDO, returns 8.22% a year on average after tax. After inflation that's about 0.20% a year in real terms. The Belka tax is charged on all the interest, including the part that merely makes up for inflation. The higher inflation is, the bigger the share of the margin the tax takes.

Our guide to inflation and your savings shows how inflation eats into savings, and the inflation calculator shows how prices have changed over the years.

How much does early redemption cost?

You can cash in any of these bonds before maturity. You can place the order 7 days after buying at the earliest (for COI, depending on the series, after 7 days or after a month), and the money arrives 5 working days later. The fees in the October 2026 offer are TOS — PLN 1.00, COI — PLN 2.00 and EDO — PLN 3.00 per bond.

With TOS and EDO the fee reduces the accrued interest and never exceeds it, so you always get at least PLN 100 per bond. With COI that holds only in year 1. From year 2 the fee is taken in full from the redemption amount, even if the interest accrued since the last payment is smaller than the fee. Just after a yearly interest payment you can therefore get less than PLN 100 per bond.

An example: you buy PLN 10,000 of EDO and order early redemption after a year. PLN 535 of interest has accrued, the fee is PLN 300 and the tax on the rest PLN 45 — you get PLN 10,190. The tables above already deduct the fee wherever a bond runs beyond the horizon — EDO over 4 years, for example.

When a bond matures, you can put the money into new bonds by exchange, at PLN 99.90 instead of PLN 100 each. An exchange costs nothing beyond the price of the new bonds, and the new bonds get the rates of the offer in force in the month of the exchange.

Is it worth holding EDO in an IKE?

An IKE (indywidualne konto emerytalne, an individual retirement account) frees you from the Belka tax if you withdraw after age 60 and you paid in during at least 5 calendar years, or more than half of the contributions went in at least 5 years before the withdrawal. PKO BP runs IKE accounts for treasury bonds (IKE-Obligacje).

With PLN 10,000 in EDO for 10 years at 4.1% inflation, an IKE gives you PLN 17,951 instead of PLN 16,440 — PLN 1,511 more.

Withdrawing before 60 is a so-called zwrot (return): you then pay 19% on the gain, as outside an IKE. In 2026 you can pay in at most PLN 28,260, and you can have only one IKE. Our guide IKE or IKZE explains how it compares with the other retirement account.

Where to buy bonds, and how safe are they?

You can buy savings bonds online at obligacjeskarbowe.pl, in PKO Bank Polski and Bank Pekao branches, at customer points of the PKO BP brokerage (Biuro Maklerskie PKO BP) and by phone. The terms of the series you buy — the first-year rate and the margin — don't change, whether later offers are better or worse.

They are issued by the State Treasury, which is responsible for redeeming them. The price doesn't change: you buy at PLN 100 and at maturity get PLN 100 plus interest. The risks lie elsewhere: inflation may outpace the rate after tax, and you may need the money sooner than you plan — then you pay the early redemption fee.

If you're wondering whether a bank deposit would be better, we compare the two in Treasury bonds or a bank deposit.