Portugal's Ten-Year Borrowing Cost Broke Through 4 Percent on Friday for the First Time Since March 2017
The ten-year Treasury bond yield peaked at 4.0141 percent on Friday before closing at 3.971. It was 3.20 percent in January. Economists blame a global bond sell-off, not Portugal, but the 2027 interest bill was already rising.
For about two hours on Friday afternoon, the Portuguese state paid more than 4 percent to borrow for ten years. The yield on ten-year Obrigações do Tesouro (Treasury bonds) crossed that line shortly after 15:00 in Lisbon and peaked at 4.0141 percent at 15:39, according to Lusa. It went back and forth across the threshold for the rest of the session and closed at 3.971 percent, fractionally below Thursday's close, according to Bloomberg data reported by Jornal de Negócios.
The last time the benchmark stood above 4 percent was 28 March 2017, when it reached 4.013 percent, Lusa reported. On Thursday it had touched 4.00 percent without going through.
A year of steady climbing
The Banco de Portugal (Bank of Portugal) publishes a daily series for the ten-year yield, and it shows how far the move has already gone. The yield was 3.20 percent on the first trading day of 2026 and fell to 3.01 percent on 27 February, its low for the year. By 18 September, the most recent day in the bank's series, it was 3.90 percent. A year earlier it had been 3.12 percent.
Shorter debt has moved faster. The two-year yield in the same series went from 2.12 percent in early January to 3.30 percent on 18 September, a rise of more than a full percentage point. ECO attributes the selling to higher oil prices and the expectation that the main central banks will have to raise rates again.
The European Central Bank has done so twice this year. Its second increase, announced in early September, took its key rate to 2.5 percent. Lusa ties the bond sell-off to higher oil and gas prices after the conflict in the Middle East and the disruption of energy shipments through the Strait of Hormuz. In mid-September, American and German bond yields reached levels last seen in 2007 and 2009 respectively.
Why economists are not alarmed
Economists see nothing specific to Portugal in the move, and that is why they are relaxed about it. Paulo Monteiro Rosa, senior economist at Banco Carregosa, told ECO that the rise "follows the movement of the main developed bond markets, a generalised sell-off of the public debt of advanced economies". A 4 percent yield "does not seem, by itself, a worrying level", he said, because the spread over German debt, at around 40 basis points, shows no increase in the risk investors attach to Portugal in particular.
He also pointed to two cushions. Public debt fell to 89.7 percent of GDP in 2025, and the average maturity of the debt is still long, at 7.5 years. Because only a slice of the debt is refinanced each year, a higher market rate feeds into the average cost of the whole stock only slowly.
The bill still grows
Slowly is not the same as not at all. The Ministério das Finanças (Ministry of Finance) already projects, in its no-new-measures framework for next year's budget, that debt service will cost about 776 million euros more in 2027 than in 2026. That projection was written before the ten-year yield went through 4 percent. We looked at how the interest bill was climbing even as the debt ratio fell in August.
The ten-year bond also matters outside the Treasury. It is the reference, as ECO puts it, for the financing costs charged to Portuguese companies, financial and non-financial alike. ING's economists, quoted by ECO, expect European long-term rates to stay exposed to whatever markets think the ECB will do next.
