Superstar firms have been in the minds of world’s leading bankers and economists lately. Policymakers are concerned that America’s leading firms such as the FAANG stocks — Facebook, Apple, Amazon, Netflix and Google — are having adverse results on the rest of us and making economic policy less predictable. Why is this? Many of the companies have improved the lives of people across the world with highly desirable and useful products. These superstar firms have also done very well for many of their stakeholders and investors. The numbers are staggering. These five tech companies together account for roughly half of the gains achieved by the Standard & Poor’s 500 stock index in 2018. And in recent weeks, Apple became the world’s first trillion-dollar corporation, with Amazon not far behind. While the superstar firms have made life easier for many consumers, it’s hard for economists not to wonder whether the effects of their stratospheric success are entirely benign.