** HK shares of Xpeng 9868.HK rise 6.2% to HK$81.8; set for biggest one-day pct rise since May 12

** Stock hits highest since August 12; second-biggest pct gainer on Hang Seng Automobile Index .HSAMI, Hang Seng Tech Index .HSTECH

** U.S.-listed shares XPEV.N rose 4.2% on Tuesday

** Chinese EV maker's Q2 revenue surges 125.3% y/y; net loss narrows to 480 mln yuan ($66.8 mln) from year-ago 1.28 bln yuan on higher deliveries

** Sees Q3 revenue doubling on surging deliveries despite challenging economic conditions

** UOB Kay Hian maintains "buy"; says 2Q25 results better than expected

** Adds sales will be driven by strong product cycle

** Citi retains "buy", lifts PT on HK and U.S. stocks to HK$114.80 from HK$113 and to $29.40 from $29

** YTD, HK stock up 72.7%, U.S. shares up 75.5%

($1 = 7.1858 Chinese yuan renminbi)

(Reporting by Donny Kwok)

((donny.kwok@thomsonreuters.com))