Why did sellers began to sell stock in September 1929?

Sellers began to sell stock in September 1929 due to growing concerns about the sustainability of the Stock Market's rapid rise and the overall economic situation. Signs of over-speculation and inflated stock prices raised alarm among investors, prompting fears of an impending market correction. Additionally, reports of declining consumer spending and economic instability contributed to a loss of confidence, leading many to liquidate their holdings before potential losses worsened. This initial wave of selling set the stage for the stock market crash in October 1929.