The price Facebook just paid to buy the mobile messaging company WhatsApp was steep: $19 billion in cash and stock. With that amount of money Mark Zuckerberg and Co. could have purchased a huge range of companies—not just start-ups, but also many of world’s biggest publicly traded firms.

The $19 billion price also includes an acquisition premium—the price paid on top of the present value of the company. But it’s still striking that 275 companies in the S&P 500 index have market capitalizations that are less than WhatsApp’s sticker price: