What event is commonly called the 1973–74 stock-market crash, in which the S&P 500 lost nearly half its value?

The 1973–74 stock-market crash was the bear market in which the S&P 500 lost nearly half its value.

From January 1973 through October 1974, the S&P 500 fell about 48%. The downturn followed the collapse of the postwar bull market and coincided with high inflation, recession, and the 1973 oil crisis after Arab oil-producing states imposed an embargo.

The crash affected markets beyond the United States and formed part of a wider period of economic instability. It is often confused with the 1970 recession-related decline, but the 1973–74 episode was substantially deeper and longer. The S&P 500 reached its low on 3 October 1974 before beginning a recovery.