Investment banks help companies and governments raise money and handle large financial deals, but they work differently than the bank where you keep your checking account.

An investment bank is a financial firm that arranges big transactions — selling stock to the public, issuing bonds, merging two companies, or buying and selling existing securities. They do not take deposits or offer mortgages. Instead, they make money by charging fees when they broker these deals, advise on strategy, or trade securities on their own account.

If you own stock or bonds, investment banks likely played a role in getting those securities to market. If you work for a company that went public or was acquired, an investment bank probably managed that process. Understanding what they do helps explain how capital moves through the economy and why certain financial events happen the way they do.

Key Takeaways

  • Investment banks raise capital for companies and governments by selling stock and bonds to investors, which is different from commercial banking.
  • They charge fees for arranging deals, providing financial advice, and executing trades rather than earning interest on deposits.
  • Investment banks also trade securities for their own profit and advise on mergers, acquisitions, and restructuring.
  • The 2008 financial crisis led to regulations separating some investment banking activities from deposit-taking banks, though the line remains blurred.

How investment banks raise capital for companies

When a company needs money to grow, it can borrow from a bank or sell ownership stakes to investors. An investment bank handles the second path. They work with the company to decide how much money to raise, what type of security to issue (stock or bonds), and at what price.

For a stock offering, the investment bank underwrites the deal — meaning they buy the shares from the company at a set price, then resell them to investors at a higher price. The difference is their profit. They also handle the paperwork, file with the Securities and Exchange Commission (SEC), and market the offering to large institutional investors like pension funds and mutual funds.

For bonds, the process is similar. The investment bank helps the company structure the debt, sets the interest rate, and sells the bonds to investors. The bank takes a fee, usually a percentage of the total amount raised. This is how most large infrastructure projects, corporate expansions, and government spending get funded.

Mergers, acquisitions, and advisory work

Investment banks advise companies on buying, selling, or merging with other firms. They research potential targets, value the companies involved, negotiate terms, and structure the deal so it makes financial sense for both sides. This advisory work can take months and involves teams of analysts and lawyers.

When a company wants to buy another, the investment bank figures out a fair price, arranges financing, and helps navigate regulatory approval. When a company wants to sell, the bank markets it to potential buyers and runs an auction process. The bank's fee is typically a percentage of the deal value — so a larger deal means a larger paycheck.

This is where investment banking becomes visible to the general public. Major acquisitions and mergers are announced in the news, and the investment banks behind them are often named in the press release. It is also where conflicts of interest can arise: a bank advising a buyer may have worked for the seller previously, or may have its own financial interest in the outcome.

Trading and proprietary investing

Investment banks trade securities — stocks, bonds, currencies, commodities — both for clients and for their own accounts. When a client wants to buy or sell a large block of stock, the bank executes the trade and takes a commission. When the bank trades for itself, it is betting that a security will move in a certain direction and profits if it does.

This proprietary trading is where investment banks can make or lose large sums of money quickly. During normal markets, it is a steady profit center. During crises, it can blow up. The 2008 financial collapse was partly caused by investment banks holding too much risky debt on their own books and losing billions when the housing market crashed.

Because of this risk, regulators now limit how much of a bank's capital can be used for proprietary trading. The Volcker Rule, part of the 2010 Dodd-Frank Act, restricts banks from trading for their own profit in ways that are too risky. The rule is complex and enforcement is ongoing, but the intent is to prevent banks from gambling with money that could destabilize the financial system.

Investment banks versus commercial banks

A commercial bank takes deposits, makes loans, and offers checking and savings accounts. An investment bank does not. Before 1933, the same firm could do both, but the Glass-Steagall Act separated them after the Great Depression. The idea was that risky trading should not endanger people's savings.

That wall came down in 1999 when Congress repealed Glass-Steagall. Now large financial institutions like JPMorgan Chase, Bank of America, and Goldman Sachs operate both commercial and investment banking divisions under one roof. This creates efficiency — one firm can finance a company's growth and handle its day-to-day banking — but also concentrates risk. If the investment side loses money, it can affect the commercial side where regular people keep their deposits.

Regulators now require these large banks to maintain separate capital reserves for each division and to pass stress tests showing they can survive a financial crisis. But the fundamental tension remains: deposit-taking banks are supposed to be safe and boring, while investment banks are supposed to be aggressive and profitable.

How investment banks make money

Investment banks earn fees in several ways. Underwriting fees come from raising capital — typically 1 to 7 percent of the amount raised, depending on the complexity and risk. Advisory fees come from mergers and acquisitions — often 0.5 to 1 percent of the deal value. Trading commissions come from executing trades for clients. And proprietary trading profits come from betting correctly on market movements.

The largest investment banks earn billions in revenue annually, but the money is not evenly distributed. A small number of senior bankers and traders earn millions in salary and bonuses. Junior analysts and associates earn much less, though still well above average. During boom years, bonuses can be enormous. During downturns, they shrink or disappear.

This compensation structure creates incentives to take risks and close deals, which is why investment banking has a reputation for aggressive behavior. A banker who brings in a large deal gets paid handsomely, even if the deal later turns out badly for the client or the market.

Regulation and the 2008 financial crisis

Before 2008, investment banks operated with minimal oversight. They could borrow heavily, trade complex securities, and hold risky assets on their own books. When the housing market collapsed, many investment banks had bought mortgage-backed securities that became worthless. Lehman Brothers, a major investment bank, failed entirely. Others like Bear Stearns were forced into emergency sales.

The government responded with the Dodd-Frank Act in 2010, which created new rules for investment banks. They must hold more capital in reserve, undergo stress tests, and limit proprietary trading. The SEC and Federal Reserve now oversee investment banking more closely. But Dodd-Frank remains controversial — some argue it does not go far enough to prevent another crisis, while others say it is too restrictive and hurts economic growth.

Investment banking today is more regulated than it was before 2008, but the basic business model remains the same: raise capital for companies, advise on deals, trade securities, and profit from the fees and gains along the way.

Frequently Asked Questions

Do I need an investment bank to buy or sell stock?

No. You can buy and sell stock through a brokerage firm or online platform like Fidelity or E-Trade. Investment banks primarily work with large institutions and companies, not individual investors. They handle the initial sale of stock to the public (the IPO), but once the stock is trading, you buy it through a broker.

What is the difference between an investment bank and a hedge fund?

An investment bank raises capital and advises on deals; a hedge fund manages money for wealthy investors and tries to earn returns by trading. Investment banks charge fees for services; hedge funds charge fees based on assets under management and profits earned. Hedge funds take more risk and are less regulated.

Can investment banks fail?

Yes. Lehman Brothers failed in 2008. Other large investment banks were rescued by the government or forced into emergency mergers. Today, stress tests and capital requirements make failure less likely, but it remains possible if losses are large enough and fast enough.

Why do investment banks pay such high bonuses?

Bonuses are tied to revenue generated and deals closed. A banker who brings in a large deal or a trader who makes millions in profit gets paid a percentage of that gain. This attracts talented people but also creates incentives to take excessive risk and prioritize short-term profits over long-term stability.

Are investment banks necessary?

They serve a real function: matching companies that need capital with investors who have money. Without investment banks, it would be harder for companies to grow and for investors to diversify. But whether the current system is the most efficient or safest way to do this remains debated among economists and policymakers.