Since the widespread deregulation of the telecoms industry from the 1990s, MVNOs (mobile virtual network operators) have become an important part of the market landscape in many countries. These companies offer mobile services under their own brand and with their own marketing, customer support, tariffs, devices and SIM cards, but use the spectrum and RAN of a host operator, and usually their core network. There are currently about 2,000 MVNOs active in the world, with half of those in Europe but the USA is both the largest single market with about 135 players. However, the recent history of US MVNOs, especially related to T-Mobile USA, reflects the big questions that surround this business model: How sustainable is it, given that…