Which Chinese stock-market benchmark fell about 30% during the 2015 China stock-market crash?

The Shanghai Composite Index fell about 30% during the 2015 China stock-market crash.

Chinese mainland shares had risen rapidly in the first half of 2015, encouraged by margin borrowing and strong retail-investor participation. The Shanghai Composite reached 5,178.19 on June 12, 2015. It then fell sharply, losing roughly 30% by early July and continuing to experience severe volatility through the summer.

The Chinese government responded with measures including trading suspensions, restrictions on some share sales, and efforts to support prices. On August 24, 2015, the Shanghai Composite fell 8.49%, and the global reaction helped produce the international market turmoil sometimes called Black Monday in August 2015.

The Shanghai Composite tracks all A-shares and B-shares listed on the Shanghai Stock Exchange. It is different from the Shenzhen Component Index and the Hong Kong-based Hang Seng Index, which represent different markets and securities.