UK jeweler Graff Diamonds Corp has postponed an up to US$1.5 billion initial public offering in Hong Kong due to “adverse market conditions,” Bloomberg reported. “Consistently declining stock markets proved to be a significant barrier to executing the transaction at this time,” the company said. Graff planned to offer 311.2 million shares at HK$25-37 apiece, according to its prospectus. The jeweler owns 18 stores globally and plans to open five others in Hong Kong, Shanghai, Macau, Hangzhou and Tokyo this year. Investors have become more cautious about IPOs in recent weeks after Facebook (FB.NASDAQ) fell 26% from its debut IPO price. China Yongda Automobiles Services (3669.JKG) canceled an IPO that would raise up to US$430 million this week because of falling prices, and sources said Sany Heavy Industry (600031.SH) cut the size of a planned share sale to US$2 billion.