Western hedge fund managers were unlikely to have been put at ease by the tone of Chinese regulators in July when, after the Shanghai Composite Index lost more than a third of its value in three weeks, they said they would investigate “malicious” short-selling practices in Shanghai and Shenzhen.

In August, the Chinese authorities froze a trading account linked to Citadel Securities, a US group that also owns hedge fund Citadel. Citadel said it continued to comply with all local laws and regulations.