Online retailer Amazon celebrated its 20-year anniversary as a listed firm on 15 May, when it listed at $18 a share. Up 63 990% since its initial public offering (IPO), Amazon ranks as the best-performing US-listed IPO since 1995, according to Dealogic. This means $100 invested in Amazon stock at the IPO would be worth nearly $64 000 today. By comparison, the total return on the S&P 500 over the same period is about 300%, according to ft.com. During the dotcom crash, its shares dropped as low as $5.51. Amazon’s market cap of $450bn comfortably exceeds the $230bn for Walmart, the largest brick-and-mortar retailer, ft.com reported.