Investment banks are involved with helping public and private companies raise funds (equity and debt) in the capital market. They are also known to give sound and helpful tips on acquisitions and mergers. Investment bankers come with a financially viable idea that is feasible and profitable for their clients. Once the client is happy and gives his mandate, the investment bank takes it upon itself to organize all the materials needed for the transaction to roll and to see the execution of the deal to fruition.
Most investment banks are known to make maximum revenue from sales and trading of financial products. This is the front office work of an investment bank. The other functions of the front office investment banks also deals in research, where these banks research companies and write reports on their prospects, with ratings like "buy" and "sell." The back office of investment banking usually deals with data-checking and analysing the credit risk associated with the daily trade transactions done by their client companies.