The Dow Jones Industrial Average lost about 11% on Black Thursday, October 24, 1929.
Heavy selling began soon after the New York Stock Exchange opened. The Dow fell 11% during the session, while trading volume reached a then-record level. A group of leading bankers later met and bought large amounts of prominent stocks, temporarily helping stabilize prices and confidence.
The respite did not last. Selling intensified again on Black Monday and Black Tuesday, October 28 and 29. Those sessions made the 1929 collapse unmistakable, although the full bear market continued until 1932. The crash was connected to excessive speculation, purchases on margin, uneven economic conditions, and weakening industrial activity.
Black Thursday is sometimes treated as the entire crash, but it was the first major panic day in a sequence. The 11% figure is also approximate because historical summaries may round the Dow’s daily percentage movement. It is distinct from the much larger 22.6% percentage loss recorded on Black Monday in 1987.