About 2.5 billion adults, just over half the world’s adult population, lack bank accounts. If we are to realize the goal of extending banking and other financial services to this vast “unbanked” population, we need to consider not only such product innovations as microfinance and mobile...

Financial systems are crucial to the allocation of resources in a modern economy. They channel household savings to the corporate sector and allocate investment funds among firms; they allow intertemporal smoothing of consumption by households and expenditures by firms; and they enable...