Investment bankers help businesses, institutions and governments to raise capital and execute transactions such as mergers and acquisitions. They also may provide market-making and security trading services.

These are all front office roles. These are the roles with the highest salaries and the best career progression opportunities.

There are also middle office roles such as risk management - the bank doesn't directly profit from these roles, but they help the front office to perform their roles better and drive revenue.

Back office roles include HR, finance, and software engineering, for example. These roles exist regardless of revenue generated and exist in most industries.

Source: Mergers and Acquisitions Article

Let's use the structure of Goldman Sachs (top investment bank) to understand this better.

Merchant Banking is the private equity arm of major investment banks. These tend to be fairly new, and smaller divisions, and conduct similar work to a private equity firm. This work entails using a little equity and mainly borrowed funds to buy a company, and then building it up to eventually sell it off at a higher price. Typically, merchant banking and private equity roles expect candidates to have prior IBD experience. This division works on the buy-side, while all other divisions are on the sell-side.

Investment/ Wealth Management refers to managing the holdings within a client's investment portfolio and trading them to reach a specific investment objective. These clients might be individual investors, or institutional investors such as pension funds, insurance companies, or governments.

Source: Investopedia Article

Markets, also known as sales and trading at other banks, is the division responsible for making markets in stocks, bonds, and derivatives. In this division, you work with asset managers, hedge funds, insurance companies, and other buy-side investors to pitch ideas and buy or sell securities or derivates. People in markets tend to specialise on a product such as fixed income, or equities.

Source: Wall Street Prep Article

Investment/ Equity Research - again, the name of this division depends on the bank. Equity research professionals produce analysis, recommendations and reports on investment opportunities for investment banks, or their clients. This research provides investors with detailed financial analysis and recommendations on whether to buy, hold, or sell a particular investment. This is similar to the kind of work you'd do as an analyst for one of the investment society's on campus.

Source: Corporate Finance Institute Article

IBD

Finally, while there is a specific division titled 'investment banking', note that all 5 of these divisions are front office roles in an investment bank. This 'investment banking' division is also known as IBD (investment banking division), or financial advisory at some boutiques, and working in this division gives you the official title of 'Investment Banker' rather than 'Trader' or 'Equity Researcher'.

At Goldman Sachs (GS), roles within IBD are separated into industry groups and product groups:

• Industry groups consist of sectors such as healthcare, and an investment banker within this group would cover all the different deal types within this sector.
• Bankers in a product group focus on a specific deal/ type of financing such as equity capital markets (ECM), leveraged finance, or mergers and acquisitions (M&A).