Which 2015 event saw China’s major stock indexes fall sharply after a speculative surge?

The 2015 event in which China’s major stock indexes fell sharply after a speculative surge was the Chinese stock market turbulence of 2015–2016.

China’s mainland equity market rose rapidly from mid-2014 into June 2015, with heavy participation by individual investors and extensive margin financing. The Shanghai Composite reached 5,178.19 on June 12, 2015, before reversing direction.

The Shanghai Composite then lost more than 40% from its June peak by late August. Chinese authorities responded with measures including restrictions on some share sales, efforts to support prices, and investigations into trading activity. Volatility returned in early 2016, when newly introduced circuit breakers were triggered and then abandoned after disrupting trading.

This episode is distinct from the Asian financial crisis of 1997–1998, which began in other economies and involved currency and banking turmoil across the region. The 2015–2016 turbulence centered on China’s domestic equity markets and followed a large, credit-fueled rally.