How the Fed Funds Rate Reaches Your Savings Account

The rate nobody actually sees directly

When the Federal Reserve raises or cuts “the rate,” what’s actually changing is the federal funds rate — the target rate at which banks lend reserve balances to each other overnight. Almost nobody outside of a bank treasury desk ever directly borrows or lends at this rate. And yet, within weeks, it shows up in your savings account APY, your credit card’s APR, and the rate quoted on a new mortgage. This post traces the actual mechanism connecting the two, because the chain is more mechanical, and more interesting, than “the Fed raises rates and banks follow.”

Step one: the overnight lending market

Banks are required to hold a certain amount of reserves, and on any given day some banks have more cash sitting idle than they need while others are temporarily short. Rather than each bank solving this alone, they lend to each other overnight in what's called the federal funds market, and the federal funds rate is the Fed's target for the interest rate on those loans. The Federal Reserve doesn't set this rate by decree directly — it influences it mainly through the interest rate it pays banks on reserves parked at the Fed itself, which creates a floor that the overnight market rate tends to track closely.

Step two: the prime rate moves in lockstep

Most consumer and small-business lending in the U.S. is priced off something called the prime rate, which is published by major banks and has, for decades, moved dollar-for-dollar with changes in the federal funds rate — typically sitting about three percentage points above it. When the Fed changes its target rate by a quarter point, the prime rate usually changes by the same quarter point within a day or two, often the same day the Fed announcement is made. This is the most direct, fastest link in the whole chain, and it's why variable-rate credit card APRs, which are almost always defined as “prime rate plus some margin,” can change within one or two billing cycles of a Fed announcement.

Step three: why savings account APYs move slower and less predictably

Unlike the prime rate, there's no formula that mechanically ties a bank's savings account APY to the federal funds rate. A bank sets its own savings rate based on how much it wants to attract or retain deposits, which depends on factors beyond the Fed's target: how much lending demand the bank currently has, how much competition it faces from other banks for deposits, and how much of its funding it can get more cheaply elsewhere. This is why online banks, which compete aggressively for deposits and have lower overhead than branch-heavy banks, tend to pass through Fed rate changes to savers faster and more fully than large traditional banks do — a large bank with plenty of existing deposits has less competitive pressure to raise its savings rate even when the Fed moves.

The practical result, visible over the last two years: when the Fed raised rates sharply, online high-yield savings APYs climbed close behind, often within one or two billing cycles. When the Fed started cutting, those same online banks cut their APYs quickly too — sometimes within days of an announcement — while many traditional branch banks, whose savings rates were never competitive to begin with, barely moved at all in either direction.

Step four: why mortgage rates don't simply follow the Fed at all

This is the part that confuses people the most: mortgage rates, especially 30-year fixed rates, are only loosely connected to the federal funds rate, and sometimes move in the opposite direction entirely in the same month the Fed changes its target. That's because long-term mortgage rates are priced primarily off the yield on long-term Treasury bonds, which reflects investor expectations about inflation and growth over the next decade or more, not the overnight rate banks charge each other today. A Fed rate cut aimed at the near term can coincide with rising long-term bond yields, if investors interpret the cut as a sign the economy needs more support than expected, which can actually push mortgage rates up in the same news cycle the Fed cuts rates.

The full chain, in order

1. The Federal Reserve sets a target range for the federal funds rate and adjusts the rate it pays on bank reserves to steer the actual overnight market rate toward that target.
2. The prime rate moves in near-lockstep with the federal funds rate, usually within a day or two of a Fed announcement.
3. Variable-rate credit cards and many home equity lines of credit, priced directly off prime, adjust quickly and predictably, usually within one to two billing cycles.
4. Savings account and CD rates adjust based on each bank's own competitive and funding decisions, often tracking Fed moves loosely and asymmetrically rather than on a fixed formula.
5. Long-term borrowing rates like 30-year mortgages respond mainly to bond market expectations about the future, which can move independently of, or even opposite to, the Fed's current target.

Why understanding the lag matters practically

If you're deciding whether to lock in a CD rate, this chain tells you something useful: a bank's current CD offer reflects both the current federal funds rate and that bank's guess about where rates are headed, baked into the term you're offered. If you're carrying a variable-rate balance, the prime rate link means you'll feel a Fed rate change in your statement almost immediately, in either direction, with very little room for your specific bank to cushion it. And if you're watching your savings APY and wondering why it hasn't moved much after a rate change, the answer is rarely a technical delay — it's usually that your particular bank has decided it doesn't need to compete as hard for your deposit as an online-only bank does.

Common questions about the Fed and your accounts