The Federal Funds Rate (FFR) is arguably the most important number in the global financial system. While it is technically a very specific interest rate used by a small group of institutions, its influence ripples through every corner of the economy. To understand the FFR, we must first look at how banks operate behind the scenes.

Banking Mechanics: The Reserve Requirement

Every day, millions of people deposit money into banks, and millions of people withdraw it. To ensure that banks always have enough cash on hand to meet the demands of their customers, the Federal Reserve requires them to maintain a certain level of "reserves" . These reserves are kept in accounts at the Federal Reserve banks.

The amount a bank must keep is known as the reserve requirement, which is a percentage of the bank's total deposits . However, a bank's balance fluctuates constantly. By the end of a business day, one bank might have more money than it needs (excess reserves), while another bank might find itself slightly short of its requirement.

The Overnight Market

To fix this imbalance, banks lend to each other. A bank with excess cash will lend it to a bank with a shortfall, usually just for one night. This allows the lending bank to earn a small amount of interest on money that would otherwise sit idle, while the borrowing bank meets its legal requirements . The interest rate they charge each other for these overnight, uncollateralized loans is the Federal Funds Rate .

The FOMC: Setting the Target

The Fed doesn't set the exact rate that Bank A charges Bank B. Instead, the Federal Open Market Committee (FOMC) sets a target range for the federal funds rate . The FOMC consists of twelve members: the seven members of the Board of Governors of the Federal Reserve System, the president of the Federal Reserve Bank of New York, and four of the remaining eleven Reserve Bank presidents who serve on a rotating basis .

The FOMC meets eight times a year to review economic data, such as:

Core Inflation Rate: How fast prices are rising for goods (excluding volatile food and energy) .
Employment Data: How many people are working and how fast wages are growing .
Durable Goods Orders: A measure of how much businesses are spending on big-ticket items .

Based on this data, they decide whether to raise, lower, or hold the target range steady. For example, in December 2024, the Fed cut the rate by 25 basis points to a range of 4.25% to 4.50% to help bolster the economy and prevent unemployment from rising .

The Prime Rate: From Banks to You

You might wonder why you should care about what banks charge each other. The reason is the Prime Rate. The prime rate is the interest rate that commercial banks charge their most creditworthy corporate customers .

By industry standard, the prime rate is usually about 3% higher than the federal funds rate. When the Fed moves the FFR, banks almost immediately adjust their prime rate. This, in turn, affects:

Credit Cards: Most credit card APRs are "variable," meaning they are tied directly to the prime rate.
Home Equity Lines of Credit (HELOCs): These usually move in lockstep with the Fed.
Small Business Loans: Many business loans are priced as "Prime + X%."

Historical Context: The Extremes of the FFR

The FFR has seen massive swings depending on the era's economic challenges.

The Volcker Era (1979-1982): To fight rampant inflation, then-Chair Paul Volcker pushed the FFR as high as 20% . This made borrowing incredibly expensive but successfully broke the back of inflation .
The Great Recession (2008): To prevent an economic collapse, the Fed slashed the rate to a record-low range of 0% to 0.25% .
The COVID-19 Pandemic (2020): The Fed again dropped rates to the 0%–0.25% floor to encourage spending during lockdowns .

FAQ: Understanding the Federal Funds Rate

Q: Does the Fed set my mortgage rate?
A: Not directly. Mortgage rates are influenced by long-term Treasury yields, but those yields are heavily affected by the Fed's target for the FFR. When the FFR goes up, mortgage rates usually follow .

Q: Why does the stock market care so much about the FFR?
A: Lower rates mean lower borrowing costs for companies, which can lead to higher profits. It also makes stocks more attractive compared to bonds, which pay less interest when rates are low .

Q: What is a "basis point"?
A: In the world of finance, 100 basis points equal 1%. So, a "25 basis point" move is a 0.25% change.

Summary Table: Impact of FFR Changes

Sector	Impact of Raising Rates	Impact of Lowering Rates
Consumers	Higher credit card and auto loan costs	Lower monthly payments on new loans
Savers	Higher interest earned on savings accounts	Lower returns on "safe" cash holdings
Businesses	More expensive to expand or hire	Cheaper to borrow for new projects
The Dollar	Usually strengthens against other currencies	May weaken, making exports cheaper