Maybe I should do some research on IPO

These days, in the capital market occurs a lot of buzzard things. The underpricing of IPO stocks is a common phenomenon.But the price down less than the offering price is wired.Air of China ,in the first trading day, it's price run below the offering price.At the end of that day,the principle owner step out to buy the cheap stocks to maintain it's price on the offering price.So it is saw a strong cash flow into the market in the last ten minutes.
Why does this event happen? It is invoved in the process of bookbuilding.In China, the rugular of bookbuilding is so informal that no tradder will tell their real price as asked.
How can we do anything to this system? There needs some research!