The Shanghai Composite’s largest single-day percentage fall during the 2015 Chinese stock-market crash was 8.5%.
The drop occurred on August 24, 2015, a day widely nicknamed Black Monday in Chinese-market coverage. It followed weeks of sharp declines that had begun after the Shanghai Composite reached a 2015 high in June. Investor concerns included slowing Chinese economic growth, falling commodity prices, and uncertainty about currency and government policy.
The Shanghai Composite is a mainland Chinese index that tracks many stocks listed in Shanghai; it is not the same as Hong Kong’s Hang Seng Index. Chinese authorities used measures such as trading restrictions, state-linked purchases, and limits on new offerings during the turmoil.
The episode also affected global markets because China had become central to trade and commodity demand. Although the one-day fall was dramatic, the 2015–2016 turbulence was a multi-month period rather than a single isolated session.