Which Chinese stock index plunged 8.5% on August 24, 2015, during China’s stock-market crash?

The Shanghai Composite plunged 8.5% on August 24, 2015, during China’s stock-market crash.

The Shanghai Composite Index measures the performance of stocks traded on the Shanghai Stock Exchange. On August 24, 2015, it suffered one of its steepest daily declines, helping give the session the nickname “Black Monday” in financial reporting. The sell-off formed part of the broader 2015–2016 Chinese stock-market turbulence.

The turmoil followed a rapid rise in Chinese share prices earlier in 2015. As prices began falling, concerns about economic growth, corporate earnings, margin trading, and government intervention encouraged further selling. The shock spread beyond mainland China, affecting stock markets and commodity prices internationally.

The Shanghai Composite is not the same as the Shenzhen Component or the CSI 300. The first is a broad index of Shanghai-listed shares, while the Shenzhen Component tracks selected companies listed in Shenzhen and the CSI 300 covers large companies from both major mainland exchanges. The 8.5% figure identifies the Shanghai index’s closing decline that day.