The selling was not limited to Black Tuesday. In fact, the Dow Jones gave up more (13%) that Monday, Oct. 28 than it did on Tuesday the 29th (12%). And then the Dow had one of its best days ever (to that point) on Oct. 30, where it recaptured the losses from Black Tuesday.

But even before then there were sell-offs, the first on Oct. 3.

There is no consensus for what caused the crash but it appears that attempts by regulators to stop speculative behavior certainly contributed. The economic cycle may have peaked but was not in recession yet. That would come later.

Sources:

• Harold Bierman, Jr., Cornell University has an essay on EH.net with a lot more detail.

• Arthur M. Schlesinger, Jr. The Crisis of the Old Order, The Age of Roosevelt 1919-1933