Repsol, Iberdrola y Acciona Energía, las ganadoras en un mes de caídas

Repsol, Iberdrola, and Acciona Energy are the standout performers in a month of declines. September is statistically one of the weakest months of the year on the stock exchange and 2026 has followed the trend, with European exchanges recording one of the few negative months of the session, owing to the resurgence of the conflict in the Middle East, central bank rate hikes, the debt market crisis, and doubts surrounding artificial intelligence (AI).

The Ibex suffers a monthly decline of 2.74% and registers its worst performance in September since 2022, when it fell by 6.59% after the sharp and rapid hikes in the ECB's interest rates to curb the surge in inflation due to the Ukraine war. The year-on-year rise has reduced to 12.24%. Repsol, Acciona Energy, and Iberdrola have shown resilience in a month when the Ibex 35's values fell by 80%.

The Spanish oil company is the clear winner, rising 9.83% in September, its best performance on the stock exchange since July, fueled by the strong revaluation of oil prices this month, which climbed by 14.63% this year. The Spanish oil company is up by 87.94% this year. During this month, EQT and Norges Bank teamed up to bid for Acciona Energy, as reported by EXPANSIÓN.

The news propelled the shares of the renewable energy firm, which climbed 2.79% in September, its best performance since May. Iberdrola gained 2.64% and broke a two-month losing streak. Other positive performers include Unicaja at 2.58% and Banco Sabadell at 0.52%. The remaining stocks fell by double digits, including Cellnex (punished by the interest rate hike and highly correlated with the debt market), Merlin, Amadeus, and ACS at 14.88%, 11.04%, 10.99%, and 10.82%, respectively.

The Ibex, alongside Italy, (-2.36%), is the least punished among the continents. The Cac Parisian deepens its decline to 4.44% due to the country's difficult fiscal situation and the Dax German suffers a 4.03% drop. Despite the doubts surrounding AI, the Nasdaq avoids the red in September, with a 1.86% gain. However, the Dow closes the month with a 4.29% decline, and the SandP 500 ends the month at 0.45%.

The true bleeding has occurred in fixed income. In September, the main sovereign bonds hit multi-decade high returns. Fears of persistently high and persistent inflation and tougher actions from central banks to curb it have driven investors to sell debt rapidly. The French 10-year bond has been the most punished and its yield increased by 68 basis points to 4.85%, the highest since 2002.

The German bond reaches multi-year highs since 2009 at 3.58%. The Spanish bond has exceeded 4% yield this month, reaching multi-year highs since 2013, and the US bond surpasses 5.2%. The euro records its worst month against the dollar since July 2025, falling by 2.44% to trade at 1.133 dollars per euro, the lowest since May 2025.

The Korea Stock Exchange plunges 19% in the quarter. Fervor for AI has boosted the main South Korean index, the Kospi, throughout much of the year. However, it has not fared as well in the last quarter. Its rises in August and September, by 3.40% and 0.26% respectively, have not been enough to erase the severe decline it suffered in July, more than 22%.

As a result, the South Korean index suffers losses of 19.33% in the quarter. Among its main companies are Samsung and SK Hynix. Over the last three months, the stock value of SK Hynix has plunged by 32.7% and that of Samsung by more than 19% due to the new doubts generated around the huge capital expenditure to finance the development of AI.

Nevertheless, the year-on-year rise is still 172% and 123%, respectively. Despite this decline, the Korea Stock Exchange still records the best performance worldwide in 2026, with a revaluation of 62.26%. It is followed by the Nasdaq, with a gain of over 16% and the Italian Stock Exchange, with a 14.30% increase.