S ong Fei is a Chinese billionaire whose wealth is derived from her family's stake in the chemical company Zhejiang Longsheng Group. The company is a global leader in the production of textile dyes, particularly disperse dyes, which are used to color polyester and other synthetic fibers. Her brother-in-law, Ruan Shuiliang, is the chairman and public face of the company.

While not involved in the day-to-day management of the chemical giant, Song's fortune is intrinsically linked to its success. The family has built a powerful, vertically integrated chemical enterprise that benefits from the massive scale of the global textile industry. The company has also diversified its operations into other specialty chemicals and has a significant real estate arm. Her ownership stake in the family-controlled, publicly traded business is the source of her considerable fortune.