All Yum Brands restaurants sell only Pepsi products because of a special partnership with the soda-maker. $84 billion-company Proctor & Gamble â the largest advertiser in the U.S. â is paired with a number of diverse brands that produce everything from medicine to toothpaste to high-end fashion. All tallied, P&G reportedly serves a whopping 4.8 billion people around the world through this network. $200 billion-corporation Nestle â famous for chocolate, but which is the biggest food company in the world â owns nearly 8,000 different brands worldwide, and takes stake in or is partnered with a swath of others.