The first Fortune 500 was published in 1955. Since that time, just three companies have held the list’s top spot: automaker General Motors, oil and gas giant Exxon Mobil, and now, Walmart. This is the seventh year in a row that Walmart has landed at number one. Its revenue in 20-18: Five hundred fourteen billion dollars. That’s up two-point-eight percent from the year before when the retailer became the first Fortune 500 company to break the half-a-trillion mark.