What banks actually do in the stock market

Banks are not just places where you keep savings. They are major players in the stock market, and they make money in ways that are separate from the interest they pay you on deposits. Understanding what banks do with stocks helps you see why their interests sometimes differ from yours.

Banks operate in the stock market through different divisions. A bank's investment banking arm helps companies sell shares to the public and advises on mergers. Its trading desk buys and sells stocks for profit. Its wealth management division invests money on behalf of rich clients. And its brokerage lets ordinary people buy and sell stocks through accounts. Each division makes money differently, and each has different rules about what it can do.

The key thing to know: when a bank trades stocks for itself, it is using its own money and taking its own risk. When it trades for you, it is using your money and you take the risk. The bank makes a fee either way.

Key Takeaways

  • Banks make money from stocks through trading for themselves, advising companies, managing client portfolios, and charging fees on brokerage accounts.
  • Investment banking and trading are separate from retail banking, and they are regulated differently to prevent conflicts of interest.
  • When you buy a stock through a bank's brokerage, the bank does not own the stock — you do, and you bear the loss if the price falls.
  • Banks are required to disclose conflicts of interest, such as when they profit from recommending a stock they also own.
  • The 2008 financial crisis happened partly because banks took too much risk with borrowed money, which is why stricter rules now limit how much they can trade with their own capital.

How banks profit from trading stocks

Banks make money by buying stocks low and selling them high, just like any trader. But banks have advantages: they have access to real-time market data, they can borrow money cheaply, and they employ teams of analysts who research companies. A bank's trading desk might hold a stock for seconds or for months, depending on the strategy.

The profit comes from the difference between the buy price and the sell price. If a bank buys 10,000 shares at $50 and sells them at $51, it makes $10,000 (minus costs). On large volumes, this adds up. But the bank also loses money when it guesses wrong — if it buys at $50 and the price drops to $48, it loses $20,000.

Banks also make money through market making. A market maker stands ready to buy stocks from sellers and sell stocks to buyers, pocketing the tiny difference between the two prices. This difference, called the spread, might be a few cents per share, but across millions of trades per day, it becomes significant income.

Investment banking and underwriting

When a company wants to sell stock to the public for the first time, it hires an investment bank to manage the process. This is called an initial public offering, or IPO. The investment bank researches the company, sets a price for the shares, and sells them to large investors and the public. The bank charges a fee, usually 3 to 7 percent of the total money raised.

The bank also takes on risk. If it cannot sell all the shares at the agreed price, it must buy the leftover shares itself. So the bank has incentive to price the stock fairly and market it well. If the stock price falls after the IPO, the bank's reputation suffers, and companies will hire a different bank next time.

Investment banks also advise on mergers and acquisitions — when one company buys another. They research the deal, negotiate terms, and arrange financing. They charge fees based on the size of the deal, sometimes millions of dollars.

Wealth management and conflicts of interest

Banks offer wealth management services to people with significant money. A wealth manager invests your money in stocks, bonds, and other assets, and charges you a fee — often 0.5 to 2 percent of the total amount invested per year. The manager makes money only if you keep money with the bank, so there is incentive to perform well.

But conflicts of interest exist. Suppose a bank's investment banking division is advising Company X on an IPO. The bank's wealth managers might recommend Company X stock to their clients, even if other stocks are better investments, because the bank profits from the IPO. To prevent this, regulators require banks to disclose conflicts and to separate the teams that advise companies from the teams that manage client money.

A wealth manager must also act in your interest, not the bank's. This is called a fiduciary duty. If a manager recommends an investment that benefits the bank more than you, and you can prove it, you may have grounds to sue. Not all financial advisors have this duty — some are only required to recommend "suitable" investments, which is a weaker standard.

Retail brokerage and how you buy stocks through a bank

Most people buy stocks through a brokerage account, often at a bank or an online brokerage firm. When you place an order to buy 100 shares of Apple, the brokerage executes the trade — it finds a seller and completes the transaction. You own the shares; the bank does not. If the price rises, you profit. If it falls, you lose.

The bank makes money through commissions and fees. Many brokerages now charge zero commission per trade, but they make money other ways: by lending your shares to short sellers (traders who bet the price will fall), by earning interest on cash sitting in your account, or by selling data about your trading patterns to hedge funds and other traders.

When you buy a stock through a bank brokerage, the bank is not recommending it — you are making the choice. But if a bank employee gives you advice, that advice must be suitable for your situation. If you are 75 years old and the employee recommends a highly risky penny stock, and you lose money, you may have a complaint.

Regulation and what changed after 2008

Before 2008, banks could trade stocks and other securities with very little restriction. They borrowed enormous amounts of money to amplify their profits. When the housing market crashed, banks had bought mortgage-backed securities worth far more than they could recover. Many banks failed or needed government rescue.

After 2008, the Dodd-Frank Act imposed new rules. Banks must now hold more capital in reserve — money they cannot lend or invest. The Volcker Rule limits how much a bank can trade stocks with its own money. Banks must stress-test their portfolios to see if they could survive another crisis. And regulators conduct regular inspections.

These rules do not prevent banks from trading stocks or making profits. They prevent banks from taking so much risk that a failure would crash the entire financial system. The rules are stricter for large banks than for small ones, because a large bank's failure affects more people.

Why bank stock recommendations matter to you

If a bank recommends a stock, you should know whether the bank profits from that recommendation. A bank might recommend a stock because its investment banking division is advising the company, or because the bank owns a large stake and wants the price to rise. These are not illegal, but they are conflicts of interest.

Before following a bank's recommendation, ask: Does the bank have a financial stake in this company? Is the person recommending it a registered investment advisor with a fiduciary duty to me, or just a salesperson? What is the bank's track record on similar recommendations? You can find conflict disclosures in the fine print of research reports, but you have to look for them.

You also have the right to move your money. If you do not trust a bank's recommendations, you can open an account at a different bank or at an independent brokerage. Competition among brokerages has driven commissions down and made it easier to switch.

Frequently Asked Questions

Do banks own the stocks I buy through their brokerage?

No. When you buy a stock through a bank brokerage, you own it. The bank executes the trade and holds it in an account registered in your name. If the bank fails, your stocks are protected by law — they belong to you, not to the bank's creditors.

Can a bank recommend a stock it owns?

Yes, but it must disclose the conflict. If a bank's research team recommends a stock that the bank's trading desk also owns, the bank must tell you about this relationship. You can then decide whether to trust the recommendation. If the bank hides the conflict, you may have grounds to complain to regulators.

Why do banks charge fees if they also make money from my trades?

Banks make money multiple ways: from commissions, from lending your shares, from interest on cash in your account, and from selling data about your trading. Fees are transparent and you can see them. The hidden profits are harder to track, which is why regulators require disclosure.

What happens to my money if a bank fails?

If a bank fails, the Federal Deposit Insurance Corporation (FDIC) insures deposits up to $250,000 per account. Stocks and bonds held in a brokerage account are not FDIC-insured, but they are protected because they are your property, not the bank's. The bank's creditors cannot claim them.

How do I know if a bank advisor is acting in my interest?

Ask whether the advisor is a fiduciary. If yes, they are legally required to put your interest first. If no, they only have to recommend suitable investments, which is weaker. You can also ask about compensation — if the advisor earns a higher commission for recommending certain products, that is a conflict of interest you should know about.