US retailer Walmart Inc on Wednesday acquired a 77 per cent stake in Flipkart for about $16 billion in its biggest acquisition till date. The deal values the 11-year old Indian e-commerce firm at $20.8 billion. Bentonville, Arkansas-based Walmart will acquire about 77 per cent stake in Flipkart, Walmart said in a statement. Sachin Bansal, who had co-founded Flipkart with Binny Bansal in 2007, would exit the company after the deal. Japan's SoftBank, an investor, will also exit the company by selling its entire 20 per cent stake in Flipkart. Sachin and Binny, who are not related and formerly worked for Amazon.com Inc, like their US rival began by selling books when they founded Flipkart.