The slow pace of the Chinese cash settlement system provided just enough time for a joint venture, co-owned by UK fund manager Schroders, to reverse the effect of an unusual "fat finger" error at the end of last year.

The mistake occurred on December 30. A member of the trading team at Bank of Communications Schroder Fund Management Company, a joint venture between Schroders and China's Bank of Communications, mistyped the number of shares held by one of its funds, the Shanghai 180 Corporate Governance ETF, according to a source close to the firm.