(Telecompaper) A subsidiary of Japanese operator Softbank will invest USD 1 billion in Korean e-commerce retailer Coupang. The investment is expected to close at the beginning of July, and will bring the total amount of funding raised by Coupang over the past year to nearly USD 1.5 billion. Coupang will use the fresh funds to boost its innovations in its fulfillment service, same-day delivery network and mobile applications. Coupang will also expand its R&D offices in Silicon Valley, Seattle, Shanghai and Seoul. Coupang reports it has reached 25 million mobile application downloads in Korea. Mobile sales currently account for over 75 percent of the company's revenue and over 85 percent of its total traffic.