Type of institutions that write securities, engage in brokerage and security trading are considered as

Type of institutions that write securities, engage in brokerage and security trading are considered as investment banks. An investment bank (IB) is a financial intermediary that performs a variety of services. Most Investment banks specialize in large and complex financial transactions, such as underwriting, acting as an intermediary between a securities issuer and the investing public, facilitating mergers and other corporate reorganizations and acting as a broker or financial adviser for institutional clients.