Mainland Chinese clients are expressing regret as Hong Kong banks increase scrutiny on opening offshore investment accounts. This tightening of access is impacting individuals who planned to invest in overseas assets through Hong Kong.

As news spread on Wednesday that Hong Kong banks were tightening scrutiny on mainland Chinese clients opening savings and investment accounts, Zhe Ye – an auctioneer based in the southwestern province of Yunnan – was stunned. The former asset appraiser had been planning a trip to Hong Kong to open an account, hoping to buy overseas assets ranging from the Nasdaq and S&P 500 to shares in newly listed companies such as SpaceX. “I really regret not opening a Hong Kong account earlier,” Zhe said...