The Exchange is back after its brief hiatus. Anna and I have some really neat stuff planned, so stick with us every morning this week. — Alex Building a consumer-facing fintech company is expensive. And if you want to build one in a sector crowded by both incumbent companies and richly funded startups, it can be super expensive. That was the lesson we learned in late 2020 by examining operating results from a number of neobanks. Neobanks are essentially software layers atop banking infrastructure, offering consumers digital-first, mobile-friendly and often…