** Shares of MGM China Holdings HKEX:2282 drop as much as 12.1% to HK$15.23, their lowest since July 28 and on course to snap three consecutive session of gains
** Stock posts biggest intraday pct decline since April 7, and is biggest pct loser among the six key HK-listed Macau gaming groups
** MGM China said its first-half net profit fell 11.2% y/y to HK$2.38 bln ($303.19 mln) but casino revenue was up 3.1% y/y
** Says its overall gaming market share was 16.2% for the six-month period ended in June, down from 16.5% the same period a year ago
** Shares of rivals also fall with Sands China HKEX:1928, Galaxy HKEX:27, SJM HKEX:880, Melco International HKEX:200 and Wynn Macau HKEX:1128 down between 0.6% and 3.8%
** Hang Seng Commerce & Industry Index HSI:HSCI and benchmark Hang Seng Index HSI:HSI both slip 0.5%
** YTD, MGM China shares up 65.8%
($1 = 7.8498 Hong Kong dollars)