SHENZHEN, Oct. 30 (Xinhua) -- All 28 stocks on China's new Nasdaq-style market for small and medium-sized companies had been temporarily suspended on its opening day Friday.

    The stocks on the ChiNext exchange in Shenzhen, Guangdong Province, had all been suspended at least once Friday under rules to prevent wild fluctuations in share prices.

    To reduce speculation, the Shenzhen Stock Exchange issued special suspension rules if any stocks fluctuate too wildly on the first day of trading on ChiNext.

    Under the rules, if any stock fluctuates beyond 20 percent from its opening price, it will be suspended for 30 minutes; if a stock fluctuates again beyond 50 percent of its opening price, it will be suspended for 30 minutes; and if a stock fluctuates more than 80 percent from its opening price, it will be suspended until 2:57p.m., three minutes before daily trading ends.

    All stocks reported rises from their IPO prices after trading began at 9:30 a.m. Friday.

    Five stocks soared more than 200 percent from their IPO prices in the morning session on Friday. Zhongyuan Huadian Co. Ltd. increased the least by 119.08 percent from its IPO price.

    But the steep hike was relieved in the afternoon session with only one stock rose more than 200 percent. Geeya Technology Co was the only one suspended for three times Friday and it soared 209.73percent from its IPO price to 35 yuan per share.

    "It's natural for the ChiNext stock prices hike to slow down in the afternoon trade session. Investors would be rational as the shares are oversubscribed and will return to its real value. The prices will continue to go down in the future," said He Chengying, general manager of the Development Research Department with Guosen Securities.

    "The key for a successful Growth Enterprise Market (GEM) should be great enterprises and great investors. But we could see the first batch of 28 enterprises on ChiNext are already mature: some have developed for more than ten years and passed high-growth periods," He said.

    "It's imperative for the regulator to select high-growth enterprises to achieve sustainable development for ChiNext," He said.

    ChiNext is aimed at providing fund-raising channels for small and medium-sized high technology businesses with high growth.

    The central bank and the financial system would continue to support ChiNext, said Zhou Xiaochuan, governor of the People's Bank of China, the central bank, at the opening ceremony.

    IPO launches in China have often seen steep price hikes followed by even steeper falls as investors snapped up quick profits.

    At the opening of ChiNext at 9:30 a.m., film production firm Huayi Brothers Media Corp. was the biggest winner, more than doubling by 122.74 percent from its IPO price, to open at 63.66 yuan per share.

    Zhongyuan Huadian Co. Ltd. increased the least by 46.26 percent from its IPO price to open at 47 yuan per share.

    Despite worries that ChiNext might lead the main board to slump, Chinese equities rose Friday with the benchmark Shanghai Composite Index up 1.20 percent, or 35.38 points, to end at 2,995.85.

    The Shenzhen Component Index grew 104 points, or 0.85 percent, to close at 12,297.16.

    Combined turnover rose to 217.03 billion yuan (31.78 billion U.S. dollars) from 190.81 billion yuan on the previous trading day.

    Shares opened higher Friday, with the benchmark Shanghai Composite Index up 1.58 percent to open at 3,007.25. The Shenzhen Component Index rose 1.92 percent to open at 12,427.1.