** Shares of online tourism services provider Tongcheng Travel Holdings 0780.HK jump as much as 13.9% to all-time high of HK$23.35

** Stock set for biggest one-day pct rise since late-September, if gains hold

** Co reports Q1 adjusted net profit up 41.1% y/y, revenue up 13.2% y/y and adjusted net margin of 18% from 14.4% a year ago

** Jefferies maintains "buy" and lifts PT to HK$24.80 from HK$24.10, saying Q1 non-IFRS earnings beat expectations and core online travel agency margin is expected to improve with solid progress in standalone app and outbound travel

** Citi reiterates "buy" on decent earnings beat

** Hang Seng Commerce & Industry Index .HSNC falls 1.3%, Hang Seng Index .HSI slips 0.7%

** YTD, stock up 12.9%

($1 = 7.8369 Hong Kong dollars)

(Reporting by Donny Kwok)

((donny.kwok@thomsonreuters.com))