The Euribor Has Overtaken the 2.5 Percent Ceiling Written Into Portugal's Savings Certificates, So September Is Where Savers Stop Sharing the Rise
The base rate on Série F cannot exceed 2.50 percent, and the three-month Euribor has not closed below that since 17 August. August paid 2.474. September stops at the cap, the first time since March 2025. Borrowers keep paying the rise; savers do not.
Portugal's savings certificate has spent eighteen months doing what it was designed to do: pass the Euribor through to households, month by month. That stops now. The three-month Euribor has risen past the ceiling written into the product, and from September the certificate pays the ceiling and nothing more.
The rule is in the IGCP's own technical sheet for Série F. The base rate is the average of the three-month Euribor over the previous ten business days, rounded to three decimal places, fixed on the antepenultimate business day of each month for the month that follows. Then comes the sentence that matters this week: the base rate may not exceed 2.50 percent, nor fall below zero.
The fixings have already made the decision
August's rate was set at 2.474 percent, after 2.356 in July and 2.215 in June. Each step tracked the market. Then the market went through the roof of the product. The three-month Euribor fixed at 2.461 percent on 3 August, reached 2.501 on 17 August, and has not been below 2.500 on any session since, ending the month at 2.573 percent on 28 August. September's rate was determined on Thursday 27 August, the antepenultimate business day, and the IGCP publishes the notice at the turn of the month, as it did on 31 July for August.
An average built from those numbers lands above 2.50 percent, and 2.50 percent is where the formula stops. That is not a first for the product, but it is a return. The base rate last stood at exactly 2.500 percent in March 2025. It fell away through that spring, reaching 2.216 percent by May 2025, and has been climbing back ever since.
What the cap does and does not touch
Two things survive the ceiling. The first is the permanence premium, added after the cap is applied and not itself capped: 0.25 percentage points from the second to the fifth year, rising in steps to 1.75 in the last two of the fifteen. A saver whose units date from 2023 is currently earning 2.724 percent, the August base plus a quarter point. The second is timing. Each subscription picks up the prevailing base rate at the start of its own quarter of interest counting, not on the first of the month.
What the ceiling does do is break the link. Every further increase in the Euribor from here is an increase savers will not receive. Borrowers will still pay it: a Portuguese home loan adds between €23 and €70 in September, and the European Central Bank meets on 10 September. The same index now moves one side of the household balance sheet and not the other.
What this means for you
- New subscriptions in September get 2.5 percent flat. Plus any permanence premium once the second year begins. Confirm the figure against the IGCP notice before you commit.
- The comparison with banks has shifted. Household deposits are at a record and term deposits shrank for the first time in a year. If bank rates keep following the Euribor and the certificate cannot, the gap closes.
- Older units are worth keeping. The premium schedule rewards a long hold far more than the base rate now can.
- The other state product is uncapped. The ten-year Treasury certificate pays up to 3.35 percent on a different structure.
- Where to buy. CTT counters, Espaços Cidadão, Banco de Investimento Global's app and digital channels, or AforroNet. The Série F limit is 250,000 units per saver, 500,000 combined with Série E, and the €5,000 online ceiling came off in July.
Portuguese savers crossed €50 billion in state certificates for the first time this month, much of it drawn in by a rate that kept rising. September is the month that money finds out the rise had a limit written into it from the start.
