The simple version

A bank makes most of its money on a spread. It lends at one rate and pays depositors another, and the difference is its net interest income. When the Federal Reserve raises rates, that spread can widen, which is why the textbook says banks like rate increases.

The same bank also owns a portfolio of fixed-rate securities bought when rates were lower, and those fall in value when rates rise. And it lends to households and businesses whose ability to repay gets harder as borrowing costs climb. All three effects arrive together. Whether the stock rises or falls on a given day depends on which one the market is weighting, not on which one is true.

The numbers

• On September 16, 2026, the Federal Open Market Committee raised the target range for the federal funds rate by 1/4 percentage point to 3-3/4 to 4 percent, by a 12 to 0 vote (Federal Reserve, FOMC statement)
• The Federal Reserve's own table of policy rate changes shows the previous increase took effect on July 27, 2023; every move in 2024 and 2025 was a decrease (Federal Reserve, Open Market Operations)
• Federal Reserve Board staff state that increases in interest rates are generally favorable for commercial bank net interest income, which they define as interest income minus interest expense, because many loan types have adjustable rates and banks do not pass through all interest rate increases to depositors (Federal Reserve, FEDS Notes, April 2024)
• The Federal Reserve's May 2026 Financial Stability Report states that higher interest rates could lead to declines in the fair values of fixed-rate assets held by financial intermediaries, which, in turn, could reduce the supply of credit to the economy (Federal Reserve)
• The same report states that in the near term, higher interest rates, as well as weaker balance sheets resulting from asset price declines, could raise consumer borrowing costs and, along with inflation, strain household budgets (Federal Reserve)
• The FDIC's 2026 Risk Review states that changes in interest rates can present risks for banks stemming from changes in securities values, declines in profitability, and funding challenges, and that credit risks represent potential for losses from loans, particularly as borrower financial conditions deteriorate (Federal Deposit Insurance Corporation)
• On Wednesday the SPDR S&P Bank exchange-traded fund, used here only as a price proxy for bank stocks, closed at 66.78 from 67.95, down about 1.7 percent, and the Financial Select Sector SPDR fund, a proxy for the S&P 500 financials sector, closed at 55.93 from 56.85, down about 1.6 percent (Yahoo Finance daily closes, September 15 and 16, 2026)
• The Dow Jones Industrial Average closed Wednesday at 51,461.90, down 631.21, and the S&P 500 at 7,551.81, down 33.92; the 10-year Treasury par yield was 5.01 percent on Wednesday and 4.94 percent on Thursday (Yahoo Finance daily closes; U.S. Treasury Daily Par Yield Curve)

The spread a bank earns

Start with the part the textbook gets right. A bank's core business is borrowing short and lending long: it takes deposits, which it can reprice quickly, and it makes loans, many of which carry rates that adjust with the market.

Federal Reserve staff put the mechanism in one sentence. Increases in interest rates are generally favorable for commercial bank net interest income, because many loan types have adjustable rates, and banks do not pass through all interest rate increases to depositors. The loan side moves up faster than the deposit side, and the gap between them is where the earnings come from.

That is the whole case for banks liking higher rates, and it is a real one. It is also only one of three things a rate increase does to a bank, and it is the one that shows up slowest, over quarters of repricing rather than in an afternoon.

What happens to what the bank already owns

A bank does not only make loans. It holds a large book of securities, mostly Treasuries and mortgage-backed bonds bought in earlier years at whatever rates prevailed then. Most of those pay a fixed rate.

When rates rise, the price of an existing fixed-rate bond falls, because new bonds pay more and the old one has to be discounted to compete. We explain why in our lesson on bonds, and the mechanism is not re-derived here. The Federal Reserve's financial stability report states the consequence for banks directly: higher interest rates could lead to declines in the fair values of fixed-rate assets held by financial intermediaries.

This is the effect that shows up fastest, because a bond's market price moves the day rates do, while a loan book reprices over many months. So on the afternoon of a rate increase, the value of what a bank already owns has already moved, and the benefit to its spread has barely started.

The borrower on the other side

The third side is the one people forget, because it is not on the bank's own balance sheet. It is on everyone else's.

Every loan is a bet that the borrower repays. A higher policy rate raises what households and businesses pay on variable-rate debt and on anything they refinance, and the Federal Reserve's own report describes the consequence as plainly as it can: higher interest rates could raise consumer borrowing costs and, along with inflation, strain household budgets. The FDIC describes credit risk as the potential for losses from loans, particularly as borrower financial conditions deteriorate.

A wider spread on a loan that stops being repaid is not a wider spread. So the same rate increase that improves the arithmetic on performing loans raises the question of how many will keep performing, and the market prices that question at the same time as the other two.

None of that is a statement about any bank's condition, and this article makes no claim that banks are healthy or troubled. It is a description of three mechanisms that a single decision sets in motion simultaneously.

The Real Cost lens on a rate move

The practical value is in reading a headline correctly, and it transfers to any company that borrows and lends.

• The spread effect is real, slow, and positive: it accrues over quarters as loans reprice faster than deposits
• The securities effect is real, fast, and negative: the bonds a bank already owns lose market value the day rates rise
• The credit effect is real, uncertain, and delayed: borrowers feel higher costs first, and any losses show up later
• A one-day move in bank stocks reports which of the three the market weighted that day, not which of the three is correct

That is why banks are supposed to like higher rates and bank stocks fell on the hike, and why neither statement contradicts the other. None of it is a view on any bank, sector, or fund.

What this means

When a rate decision moves bank stocks, the question that clarifies it is which of the three effects the day's move is pricing. The spread is the slow one; the securities are the fast one; the borrowers are the delayed one.

The broader idea is that a business sitting on both sides of a price does not simply win when the price moves. It wins on one side, loses on another, and takes on a question about its customers on a third, and the net depends on timing that no single day resolves.

What this is NOT

This is not a view on any bank stock, the banking sector, or any fund, and the two exchange-traded funds cited are named only as published price proxies. No bank or institution is named. This is not a claim that banks are healthy or that banks are troubled, and it makes no reference to any bank's condition. This is not a forecast of rates, bank earnings, or credit losses, and it asserts no magnitude for any of the three effects. This is not a position on whether the rate increase was correct. The FEDS Note cited presents its authors' views, not necessarily those of the Federal Reserve Board. This is not investment or financial advice of any kind.

Sources

• Federal Reserve, FOMC statement, September 16, 2026 (the target range and the vote): https://www.federalreserve.gov/newsevents/pressreleases/monetary20260916a.htm
• Federal Reserve, Open Market Operations, policy rate changes by year (the July 27, 2023 increase and the 2024 and 2025 decreases): https://www.federalreserve.gov/monetarypolicy/openmarket.htm
• Federal Reserve, FEDS Notes, Is This Time Different: How Are Banks Performing during the Recent Interest Rate Increases Compared to 2004-2006?, April 12, 2024 (net interest income defined, and why rate increases are generally favorable to it): https://www.federalreserve.gov/econres/notes/feds-notes/is-this-time-different-how-are-banks-performing-during-the-rir-increases-compared-to-2004-2006-20240412.html
• Federal Reserve, Financial Stability Report, May 2026, Near-Term Risks to the Financial System (fair values of fixed-rate assets; consumer borrowing costs and household budgets): https://www.federalreserve.gov/publications/2026-may-financial-stability-report-near-term-risks.htm
• Federal Deposit Insurance Corporation, 2026 Risk Review (interest rate risk and credit risk described): https://www.fdic.gov/analysis/2026-risk-review
• U.S. Treasury, Daily Par Yield Curve Rates, September 2026: https://home.treasury.gov/resource-center/data-chart-center/interest-rates/TextView?type=daily_treasury_yield_curve&field_tdr_date_value_month=202609
• Yahoo Finance, daily closes for KBE, XLF, the Dow Jones Industrial Average, and the S&P 500: https://finance.yahoo.com/quote/KBE/history/