Investment banks are financial institutions that assist companies, governments, and other entities in raising capital. They do this by underwriting and issuing securities, such as stocks and bonds. Investment banks also provide advisory services for mergers and acquisitions, helping clients navigate complex financial transactions and make informed decisions. In addition to capital raising and advisory services, investment banks engage in trading and market-making activities. They buy and sell securities on behalf of clients and their own accounts, aiming to profit from market fluctuations. Overall, investment banks play a crucial role in the financial system by facilitating the flow of capital and providing expert financial guidance.