New shares in Hong Kong are generally divided into two parts: international placement and public offering. 90 per cent of the shares are allotted internationally. Sponsors and underwriters are investment banks or brokers who allot shares to more powerful funds, institutions or individual clients. Generally speaking, such clients have to have an asset value of more than HK $30 million or a portfolio of more than HK $8 million to qualify for placement. The other 10% is a public offering for all investors to subscribe for.
If the public offering is very hot (oversubscribed multiple), it will be refunded to the public for sale in the international market, for example, more than 100 times, 50% will be redialed to the public offering, then the international placing and the public offering will become 50% each. Here gem and motherboard are the same callback mechanism.