** Shares of Hong Kong Exchanges and Clearing Ltd fall as much as 4.7% to HK$493, their biggest daily percentage decline since July 27
** Stock is the biggest percentage decliner on the Hang Seng Finance Index and the fourth-biggest decliner on the benchmark Hang Seng Index
** UBS maintains "buy" rating on the stock saying potential market expansion and composition improvement are not yet fully priced in, but it cut TP to HK$592 from HK$604 to reflect slight earnings revision
** Brokerage Nomura maintains "neutral" on the stock but trims TP to HK$511.80 from HK$514.30 saying H1 earnings is below forecast amid lower investment gains
** Hong Kong Exchanges, which posted a 26% rise in first-half profit on Wednesday, said Q2 and start of Q3 trading volumes returned to similar levels as H2 2020
** Hong Kong Exchanges head also expects flood of Chinese company listings on the exchange due to regulatory changes on the mainland and in the United States
** The Hang Seng Finance Index slips 0.8% and the benchmark index eases 0.1%
** As of last close, the stock had surged 21.8% this year