Investment banking is a type of banking that organizes large, complex financial transactions such as mergers or initial public offer (IPO) underwriting. 

Thereby professionals involved in these banks and these processes are referred to as investment bankers.

While typically, a fresher usually starts a career in investment banking at the analyst position, one can typically rise to the position of associate and director, after several years.

A career in investment banking in itself is highly rewarding and often leads to a fairly rapid career progression.