The 1929 stock market crash is conventionally said to have occurred on Thursday the 24th and Tuesday the 29th of October. These two dates have been dubbed "Black Thursday" and "Black Tuesday," respectively. On September 3, 1929, the Dow Jones Industrial Average reached a record high of 381.2. At the end of the market day on Thursday, October 24, the market was at 299.5 — a 21 percent decline from the high. On this day the market fell 33 points — a drop of 9 percent — on trading that was approximately three times the normal daily volume for the first nine months of the year. By all accounts, there was a selling panic. By November 13, 1929, the market had fallen to 199. By the time the crash was completed in 1932, following an unprecedentedly large economic depression, stocks had lost nearly 90 percent of their value. \n\nThe events of Black Thursday are normally defined to be the start of the stock market crash of 1929-1932, but the series of events leading to the crash started before that date. This article examines the causes of the 1929 stock market crash. While no consensus exists about its precise causes, the article will critique some arguments and support a preferred set of conclusions. It argues that one of the primary causes was the attempt by important people and the media to stop market speculators. A second probable cause was the great expansion of investment trusts, public utility holding companies, and the amount of margin buying, all of which fueled the purchase of public utility stocks, and drove up their prices. Public utilities, utility holding companies, and investment trusts were all highly levered using large amounts of debt and preferred stock. These factors seem to have set the stage for the triggering event. This sector was vulnerable to the arrival of bad news regarding utility regulation. In October 1929, the bad news arrived and utility stocks fell dramatically. After the utilities decreased in price, margin buyers had to sell and there was then panic selling of all stocks.