S&P 500 Eylül sezonu: Yatırımcıların izlemesi gerekenler

S&P 500 September seasonality: What investors should watch

Mon, August 31, 2026 at 3:08 PM GMT+3 2 min read

Wall Street is entering September with the S&P 500 close to record territory but facing a cluster of risk signals that analysts say warrant attention, even if the seasonal case for alarm is less clear-cut than commonly presented.

The S&P 500 has stayed within 2% of its record high above 7,800 throughout August. The index has gained 12.72% year to date, with the Nasdaq Composite up 14.23% and the Dow Jones Industrial Average up 10.72%.

September has a well-known reputation as the worst month of the year for stocks. But Ryan Detrick, chief market strategist at Carson Group, argued that the current setup may temper those concerns. When August finishes positive and the year's gain falls between 10% and 17.5% — conditions that match 2026 — September has averaged a 1.0% gain going back to World War II, according to Benzinga. Ryan Detrick also noted that in such conditions, the last four months of the year have finished higher in 10 of 11 instances, with an average gain of 5.6%.

Still, Ryan Detrick cautioned that midterm-election-year dynamics can bring turbulence in August and September. He identified 7,610 — the S&P 500's June 2 peak — as a key support level to watch, according to Benzinga.

CNBC's Mike Santoli flagged a separate set of market signals that he said warrant vigilance independent of the calendar. The CBOE Volatility Index has dropped under 15 — a reading Santoli called "eerie complacency" — which he found notable because seasonal patterns typically push volatility higher around this point on the calendar. The 10-year Treasury yield climbed back above 4.7% after Fed Chairman Kevin Warsh used his Jackson Hole appearance Friday to convey that the committee views short-term rate increases as the appropriate response to persistent inflation — and that one could come soon, according to CNBC.

Pricing in fed-funds futures put the probability of a September hike at roughly 50% in the wake of Warsh's address, according to CNBC. Santoli argued that such evenly split odds, arriving weeks before a policy meeting, tend to keep investors from taking on additional risk.

Sentiment data also leans cautious. John Kolovos of Macro Risk Advisors characterized the latest sentiment reading as broadly unchanged but tilted in a worrying direction, with traditional surveys like Investors Intelligence registering too many bulls and real-time market data pointing to elevated complacency.

Earnings concentration is another factor. Charles Schwab's analysis found that just two companies — Nvidia and Micron — are driving roughly a third of the market's total 2026 profit growth, while the ten largest earnings contributors collectively explain about two-thirds of it.