The Autumn Market Effect: What Seasonality Can (and Cannot) Teach Investors

Mike Perros

Published on: 30/09/2025

October has a reputation for being “the scary month” on Wall Street, thanks to infamous crashes in 1929 and 1987. But the truth is more balanced: while October has seen dramatic headlines, it isn’t the worst-performing month historically - that distinction belongs to September. The real lesson isn’t about predicting which month will bring turbulence. It’s about preparing for volatility whenever it comes. A strong financial plan, grounded in diversification and long-term goals, offers far more security than trying to outguess the calendar.