** Chinese property developer Shimao Group Holdings" (0813.HK) shares soar as much as 25.7% to HK$5.91, biggest daily pct gain since debut in July 2006 ** Stock hits highest since Dec. 17, on course to snap two sessions of losses; biggest pct gainer in Hang Seng Composite index tracking properties and construction stocks (.HSCIPC) ** Shimao has put all its projects on sale, local media reported, as Chinese property developers face mounting pressure to negotiate with their creditors to ease a liquidity squeeze in a sector that is threatening to push more firms into default read more ** Company has struck a deal with a Chinese state-owned firm to sell its Shimao International Plaza Shanghai for over 10 bln yuan - report ** Daiwa downgrades Shimao"s shares to "hold" from "buy", cuts PT to HK$5.20 from HK$20, saying the company will find itself in a "vicious cycle of liquidity issues" given the recent negative news, even though Shimao said it is not in debt servicing default ** Company"s property services unit Shimao Services (0873.HK) jumps 14% ** Hang Seng Mainland Properties index (.HSMPI) soars 3.8% and (.HSCIPC) surges 1.9%, while the Hang Seng index (.HSI) rises 1%