There are a large number of activities which are included under the heading of financial services. Among those services are, transferring funds, investing, money management, lending of money and many other types of services.
One of the most important financial services offered is investment banking services. Technically this refers to an area of corporate finance that allows large, usually institutional clients to organize the funds they need, usually by issuing securities either for equity or debt. Investment bankers advise their clients how to best go about merging with other companies, or acquisition of another company, and other complex financial transactions.
The line between an investment bank, sometimes called an I-bank, and traditional commercial banks is very thin, with each type of bank dabbling into the realm of the other type more and more often. As I-banks continue to become more diversified, this distinction will become less meaningful, and investment banks and commercial banks will start to look more and more alike.