Despite being largely confined to the Mexico and Brazil region, challenger Bank Nubank has reached a milestone of 25 million customers. After being founded in 2013, the bank took a slow start to growth but is now averaging about 42,000 new clients a day, according to reports. As of July 2019 the challenger bank hit a valuation of around $10 billion USD. How come Nubank is growing so fast? this article suggests that less competition coupled with a larger un/derbanked population might be the key to their success.