4. Alibaba float becomes the largest IPO in history

E-commerce giant Alibaba Group Holding Ltd made its public debut on the New York Stock Exchange on Sept 19. The company raised a record $21.8 billion in its initial public offering, which valued it at $231.4 billion, larger than Amazon.com Inc and eBay Inc combined.

Alibaba's shares closed up 38 percent on the first day of trading. Its IPO now ranks as the world's largest at $25 billion, after some shareholders exercised an option to boost the deal. The previous IPO record was set in 2010, by Agricultural Bank of China Ltd.