China's stock market sinks into bear territory as CSI 300 extends 10-week rout

China's CSI 300 slid into a bear market on Thursday, closing 20% below its June peak as a 10-week rout in mainland equities showed no sign of easing.

The index tracks 300 of the largest stocks listed in China, which makes it the country's benchmark gauge of large-cap sentiment. A 20% drawdown meets the conventional definition of a bear market, and the decline has now stretched across 10 weeks, a duration that points to sustained selling rather than a single-session shock.

The source frames the move as a deepening selloff, not a stabilizing one. That matters for positioning: the slide has run from the June high to Thursday's threshold break without a reversal strong enough to interrupt the trend.

Interpretation: crossing the 20% line often triggers mechanical and psychological shifts. Some systematic and mandate-driven investors treat bear-market status as a signal to cut exposure, which can feed further selling. Whether that dynamic plays out here is not established by the reporting, but the 10-week persistence makes it a live risk worth respecting.

The decline also puts the CSI 300 among the clearer risk-off signals in Asian equities at the moment, given its role as China's primary large-cap benchmark.