An investment bank is an institution that can act as an agent or underwriter for companies that wish to issue securities or equity. Investment banks differ from commercial banks, since they don't accept deposits or provide loans to individuals. Generally an investment bank will have a financial markets operation in which dealers and/or brokers are employed. Under this operation, the investment bank will make markets in foreign exchange, money markets, commodity markets, etc., and maintain a secondary market for previously issued securities. This is done by quoting buy and sell prices to their customers. These customers also include other banks. Another type of service investment banks provide to their investors is advisory services.

投资银行是能够充当想要发行有价证券或股票的公司代理人或担保人的机构。投资银行不同于商业银行，因为他们不接收存款或提供个人贷款。一般，投资银行有一个金融市场运作系统，在这个系统中雇佣了代理人和/或经纪人。在这个运作系统下，投资银行会变成外汇市场、货币市场、商品市场等，对于先前发行的有价证券维持二级市场。通过给他们的客户提供买卖价格来做到这点。这些客户还包括其他银行。另一种服务投资银行提供给他们的投资者，那就是咨询服务