San Francisco-based Chime is part of a digital banking sector that has seen a dramatic increase in interest from global investors in recent years. Berlin-based mobile bank N26 recently launched in the U.S. and raised a new funding round in July that valued it at $3.5 billion. U.K.-based Revolut Ltd., last valued at $1.7 billion, also opened up shop in the U.S. And in Brazil, DST-backed NuBank has raised almost $1 billion since its founding in 2013, and has a reported valuation of $10 billion.