Each September, the Australian sharemarket confronts a recurring reckoning — a month shaped by structural mechanics, historical misfortune, and the quiet anxiety of investors who have seen this pattern before. Over two decades, the ASX200 has averaged losses of 0.47 per cent in September, a figure modest in isolation yet vast in consequence, with billions erased in recent years. The causes are neither purely cyclical nor purely coincidental, but a layered confluence of earnings exhaustion, dividend adjustments, and the market's uncanny habit of meeting its worst moments in this particular mont