** Weimob 2013.HK jumps 16.9% to HK$2.84, highest since February 27

** Stock set for biggest one-day pct gain since May 15

** Chinese digital commerce and media services group says its chairman and CEO, SUN Taoyong, bought 4 million shares - 0.11% of issued share capital, at avg price of HK$2.44 in open market on August 22, raising his stake in co to 6.76%

** Says SUN may further raise his shareholding at when appropriate opportunities arise

** YTD, stock down ~16%

(Reporting by Donny Kwok)

((donny.kwok@thomsonreuters.com))