History Says the Nasdaq-100 Does This in September. AI Investors Should Take Note.

Historical market data indicates that September has consistently proven to be a challenging month for equities, with the Nasdaq-100 posting an average decline of 2.1% during the month between 2017 and 2025. Over that period, the index generated negative returns in 67% of Septembers, including sharp pullbacks such as a 10.6% drop in 2022 and declines exceeding 5% in 2020, 2021, and 2023. High-profile constituents, particularly semiconductor and artificial intelligence leaders like Nvidia, have frequently mirrored this seasonal volatility. Despite the recurring September weakness, historical trends reveal stronger momentum in subsequent months. The Nasdaq-100 delivered average gains of 1.1% in October and 4.2% in November between 2017 and 2025, with November finishing positive 78% of the time. Financial research cautions against market timing, noting that missing the market's strongest days significantly impairs long-term compounding. Consequently, analysts emphasize maintaining positions and viewing potential seasonal pullbacks as potential accumulation opportunities.