September 2026: Market Rally or Correction? How Investors Are Positioning at Month Start

Key Takeaways

• September is the only month with a long-term negative average: Since 1928, the S&P 500 has lost an average of around 1.2% in September, closing lower in 56% of years.
• US midterm election years like 2026 intensify September weakness: In the past ten midterm Septembers, the S&P 500 fell six times, averaging around -2%.
• The critical technical level for the S&P 500 is at 7,638 points – a break of this support would, according to Elliott Wave analysis, open the path toward 7,121 to 7,190 points, corresponding to a decline of more than 6%.
• The 98-year composite of the S&P 500 typically shows a high in late August, followed by a downward movement through September into early October.
• The RSI(5) stands at 53, the rolling MACD shows a negative histogram – both suggest weakening upside momentum toward the end of August 2026.

The S&P 500 closed on Monday, August 31, 2026, at 7,703.88 points – slightly below the previous day's level. At the month transition, investors face the question: Will September bring a continuation of the uptrend or a historically typical correction? The DAX and Euro Stoxx 50 also show slight weakness with losses of 0.53% and 0.12% respectively.

Historical September Weakness: Statistics Tell a Clear Story

Seasonality refers to recurring patterns in stock markets that occur at certain times of the year. September is regarded as the statistically weakest stock market month. Since 1928, the S&P 500 has lost an average of around 1.2% in September. In approximately 56% of years, the index closed lower – making September the only month with a long-term negative average, as shown by historical data.

A 98-year composite of price movements from August 27 through year-end displays a characteristic pattern: typically a high in late August, followed by a downward movement through September into early October. The 25-year composite shows an even sharper decline, reaching its bottom near month-end before a recovery from October through December.

2026 as a US Midterm Election Year: An Additional Burden

2026 is a US midterm election year – a factor that has historically intensified September weakness. In the past ten midterm Septembers, the S&P 500 fell six times, averaging around -2%. Since 1942, midterm election years also show a negative September average, with October frequently marking the turning point.

The combination of seasonal weakness and the election cycle increases the risk of a correction at month start. Investors thus monitor not only technical support levels but also political developments ahead of the November elections.

Critical Technical Levels for the S&P 500

According to Elliott Wave analysis from August 29, 2026, a bearish scenario treats the mid-August high as Wave 5 of W-3 and positions W-4 as an a-b-c correction downward. The next break downward would mark Wave 3 of W-c.

Key support lies at 7,638 points. Above this level, a bullish alternative targeting around 7,940 points could prevail. A break, however, would open the path toward 7,121 to 7,190 points – a projected target for a seasonally driven decline. This area lies near the 200-day simple moving average at 7,119 points.

Short-term moving averages are positioned at 7,689 to 7,712 points (10- and 20-day averages). Should the central support zone at 7,638 break, a rapid, seasonally driven decline is expected that could pull the market down by more than 6% in the coming weeks.

Momentum Indicators Show Weakening Dynamics

The RSI(5) stands at 53 on August 29 – a neutral value that signals neither overbought nor oversold. The rolling MACD, however, shows a negative histogram, pointing to weakening upside momentum. Both indicators fit the picture of a market standing at a critical turning point.

How Are Investors Positioning Themselves? Strategic Considerations

The stock market adage "Sell in May and go away" is familiar to many investors. A more modern version states: "Sell in May and go away, but remember to come back in September" – meaning investors should sell their stocks in May and only re-enter the market in September. This strategy is based on the observation of recurring weak phases between May and October.

At the start of September 2026, investors face a decision: Wait and maintain liquidity, or buy counter-cyclically into a possible weak phase?

Factors That Can Influence Seasonal Patterns

Seasonal patterns are not automatic. Several factors can either reinforce or override them:

• Quarter-end effects: Institutional investors rebalance their portfolios as of September 30, which can lead to increased trading volumes.
• Holiday periods: During peak vacation periods, trading volume drops, which can increase volatility.
• Tax considerations: At year-end, some investors deliberately sell losing stocks to realize tax losses.
• Global events: Elections, geopolitical tensions, or major economic announcements can influence or temporarily override seasonal patterns.
• Economic cycles: Recessions or growth phases overlay seasonal effects.

Outlook for Autumn: October and Year-End Phase

Historical data shows that September weakness is often followed by a recovery in the fourth quarter. Both the 98-year and 25-year composites show an upward movement from October through December. Some analysts refer to this period as the "year-end rally."

According to Yardeni Research, the winter months tend to be among the stronger periods in stock markets. However, here too: historical patterns offer guidance, not guarantees.

Bonds as an Alternative? Review Investment Strategy for 2026

The German Institute for Retirement Provision recommended in early January 2026 that investors review their investment strategy. A pronounced interest rate cutting trend increases the chances of outperformance by bonds. Often, bonds have outperformed stocks in certain phases, even though stocks are considered the winners over a long time horizon.

At the current time, it remains to be seen to what extent central banks adjust their monetary policy and whether this further increases the attractiveness of bonds.

Conclusion: Caution Warranted, But No Automatic Crash

The combination of historical September weakness, US midterm election year, and technical warning signals suggests caution. The key level at 7,638 points in the S&P 500 will likely be closely watched in the coming days. A break could trigger a multi-week correction, while holding this support leaves room for a bullish alternative.

Investors should be aware that seasonal patterns represent statistical tendencies, not deterministic laws. Global events, quarterly earnings, or monetary policy decisions can change direction at any time. A balanced positioning with an eye toward risk management appears appropriate at the month's start.