Hong Kong's Securities and Futures Commission has warned of potential volatility in China Star Entertainment (HKG:0326) shares due to a high concentration of ownership, according to a Friday bourse filing.

According to the filing, the chairman and vice chairman controlled 67.5%, while 19 shareholders and their related parties collectively held 23.8% of the issued shares. Combined, these insiders accounted for over 91% of the total shareholding.

As of June 27, just 8.6% of the company's shares were held by public investors.

China Star shares surged 543% from HK$0.53 on March 18 to HK$3.41 as of July 10, the filing said.

The SFC urged extreme caution, noting that even small trades could lead to substantial price swings due to limited free float.