55Tuan, a China-based group-buying site that provides users with daily deal offers, has received US$50 million in a financing round from existing investors, including alternative asset fund manager CDH Investments and venture capital firm Zero2IPO Capital. The company previously raised US$200 million from CDH, Zero2IPO, venture capital firm Shanghai GSI Investment and investment manager Tianjin Redbud Capital Investment in 2011. The new capital will be used to expand the company's services to additional cities and develop its mobile business.