The shadow banking system is a term that is used to describe the institution which helps in the creation of credit across the globe but they are not regulated like the traditional banking system. They mainly remain unregulated like lenders in rural areas, brokers, credit agencies. The shadow banking system arises because the traditional banks were not able to serve the needs of all parties.
These days many advanced forms of shadow banks have come up like asset-backed commercial paper conduits, credit hedge funds, Structured Investment vehicles, Money market funds, Securities lenders.
They do also perform the traditional function of lending funds but unlike traditional banks, they do not take deposits from retail clients at a large scale. Also, they specialize in their area, unlike banks which have different departments dealing with different services. In a way, these institutions have done great work in credit creation and distribution.