We Can’t Tell How Bad Things Really Are

Stocks had been dropping nervously for weeks. Black Thursday—October 24, 1929—wasn’t as bad as the Black Monday or Black Tuesday that followed. And it wasn’t the beginning of the downturn that became the Great Crash. But something petrifying happened that day, around 10 a.m. Before that hour, prices were firm. Trading volume, though, was extremely heavy. So heavy that the stock ticker, which depended on the manual input of information and could print no more than 268 characters a minute, couldn’t keep up.

This had happened before. The average number of shares trading hands on the New York Stock Exchange had doubled and doubled again over the previous decade. And for a year now, traffic noted in 1928. “When the tape falls behind for ten minutes or half an hour the Exchange and its doings drop, as it were, behind a cloud. As a result the humble ticker—which everyone has taken for granted up to now—has suddenly become the big problem of the stock market.”