China is tightening the grip over quantitative trading after experiencing its own version of a “quant quake,” a reference to the summer of 2007 when a number of high-profile and successful US-based hedge funds suffered outsized losses.

The Shanghai and Shenzhen bourses froze the accounts of Ningbo Lingjun Investment Management Partnership for three days after the hedge fund dumped 2.57 billion yuan ($360 million) in shares at the open on Monday. That morning, just as traders returned from a week-long Lunar New Year holiday to a jittery market that had barely recovered from a major rout earlier in the month, the blue-chip CSI 300 Index slipped as much as 0.9%.