European equities have entered what is historically the most challenging stretch of the calendar year, as August and September consistently deliver the weakest returns for the region’s stock markets.
Following a strong first half in 2025 and a slightly positive July, history suggests that the summer momentum in European equities often loses steam as August arrives.
The month is typically defined by thinner trading volumes, greater market sensitivity to economic and geopolitical headlines, and a consistent pattern of higher volatility.
August: The weakest month for European indices
Analysis of the past three decades reveals a clear seasonal downturn in August.
The EURO STOXX 50, Europe’s blue-chip benchmark, has averaged a 1.66% decline during the month over the past 30 years, making it the worst-performing month of the year.
It has ended August in positive territory only 43% of the time, and the broader STOXX Europe 600 tells a similar story.
Over the past 24 years, this index has fallen by an average 0.7% in August, also with a 43% winning ratio. The most brutal August came in 1998, when the EURO STOXX 50 plunged 14.4%, followed closely by 2001’s 13.79% loss.
Country indices echo August’s negative trend
Zooming in on national markets, the pattern of August weakness is equally pronounced.
This period is the weakest month for Germany’s DAX, which posts an average decline of 2.2% and finishes in positive territory just 47% of the time.
In France, the CAC 40 drops by 1.47% on average in August, narrowly ahead of September’s 1.49% average fall, and sees only a 37% winning rate.
Italy’s FTSE MIB and Spain’s IBEX 35 also see the negative sign, logging average August losses of 0.7% and 0.9%, respectively.
German stocks: Some of the weakest August seasonality
A group of Germany’s blue chips consistently show downward August bias, with some of them marking it as their worst month of the year, both in terms of returns and win probability.
According to TradingView data, some of the hardest-hit stocks include:
• Thyssenkrupp AG leads the decline, tumbling an average 4.6% in August with a win rate of just 30%, meaning it has posted gains in only 9 of the past 30 years.
• BMW AG averages a 4.1% loss in August with just a 37% win rate. Volkswagen AG, meanwhile, falls 3.3% and ends the month higher only 27% of the time — proof that even automakers aren’t spared from late-summer volatility.
• Deutsche Bank AG, Germany’s largest lender, averages a 3.47% drop in August and matches Thyssenkrupp’s 30% win ratio.
• Utility giant E.ON SE and industrial titan Siemens AG also feel the seasonal drag, both slipping by nearly 2%, with win rates of 37% and 40%, respectively.
• Deutsche Börse AG, operator of Germany’s stock exchange, and consumer goods firm Beiersdorf AG both see their weakest performance in August, falling 1.72% and 1.66% on average, with win rates of 48% and 39%, respectively.
Bottom line: August’s seasonal slump hard to ignore
With the EURO STOXX 50 and STOXX 600 up 8% and 7%, respectively, European equities have delivered a solid year-to-date performance.
Much of this rebound has come on the back of a strong recovery from April’s tariff-induced downturn, mirroring a broader global equity upswing.
But history warns that August marks a persistent seasonal soft spot — particularly for Germany’s corporate heavyweights, which tend to underperform more than their European peers.
From broad indices to blue-chip stocks, the month shows a consistent pattern of lower returns, thinner liquidity, and heightened vulnerability to negative news flow.
While no seasonal trend guarantees future performance, August remains, by many measures, the most challenging month for European investors.
