HONG KONG, Dec 24 (Reuters) - The shareholding of China Evergrande Group"s (3333.HK) chairman in its property services unit has fallen to 58.18% from 60.96% after forced selling of pledged shares by a third party, a Hong Kong stock exchange filing showed. The number of Evergrande Property Services Group (6666.HK) shares involved was 300 million, and the drop was the result of steps taken on Dec. 20 to enforce rights to the shares held as security against chairman Hui Ka Yan, the filing said. Reuters could not immediately determine who sold the pledged shares. The stake was worth roughly HK$798 million ($102.32 million), based on the stock"s closing price of HK$2.66 on the day. Shares of Evergrande Property Services Group ended 1.5% lower on Friday at HK$2.63. Evergrande Group, grappling with over $300 billion in liabilities and at risk of becoming China"s biggest ever default, has been scrambling to raise cash by selling assets and shares. Hui"s stake in Evergrande Group itself dropped to 59.78% earlier this month, also on forced selling. read more " ($1 = 7.7989 Hong Kong dollars)