A more thorough explanation:

An investment banker is a person or institution that helps businesses raise capital by underwriting or selling stocks or bonds. They may also trade securities at an investment bank. Investment bankers work with companies to determine the best way to raise money, whether it's through an initial public offering (IPO), a bond offering, or another method.

For example, if a company wants to go public and sell shares of stock to the public for the first time, they may hire an investment banker to help them with the process. The investment banker will work with the company to determine the best price for the shares and help market the offering to potential investors.

Another example is if a company wants to issue bonds to raise money. The investment banker will help the company determine the terms of the bond offering, such as the interest rate and maturity date, and then sell the bonds to investors.

Overall, investment bankers play an important role in helping businesses raise money and grow.