How monetary policy works
The Federal Reserve (the Fed) is the US central bank. Its mission is to keep the economy healthy by balancing two goals that often pull against each other.
Maximum employment
Keep as many Americans working as possible. The Fed targets around 4% unemployment β the "natural" rate where the labor market is in balance.
Price stability
Keep inflation at roughly 2% per year β enough to lubricate economic activity, but not so much that it erodes savings and purchasing power.
The Fed's primary lever is the federal funds rate β the interest rate banks charge each other for overnight loans. By moving this rate, the Fed influences borrowing costs across the entire economy.
How a rate change ripples through the economy
Who makes the decisions?
The FOMC
The Federal Open Market Committee sets rate policy. It has 12 voting members and meets 8 times per year.
7 governors
Appointed by the president, confirmed by the Senate for 14-year terms. Always vote.
5 regional presidents
12 regional bank presidents rotate voting seats each year (NY Fed always votes).
Tight vs easy policy
Tight (hawkish) policy = higher rates β more expensive borrowing β less spending β inflation falls.
Easy (dovish) policy = lower rates β cheaper borrowing β more spending β economy stimulated.
The challenge: the effect of rate changes takes 12β18 months to fully show up in the economy, so the Fed must act based on forecasts, not just current data.
The Fed's toolkit
The Fed has multiple instruments at its disposal. Some are used routinely; others are reserved for crises.
Federal funds rate
The primary tool. The FOMC sets a target range for overnight interbank lending. Every other rate in the economy tends to follow it over time.
Open market operations
The Fed buys or sells Treasury securities to add or drain reserves from the banking system β the mechanism for keeping the fed funds rate on target.
Reserve requirements
The fraction of deposits banks must hold in reserve. Cut to 0% in 2020; now rarely used as an active policy lever.
Discount window
Direct loans to banks at the "discount rate." Acts as a backstop against bank runs. Borrowing carries a stigma in normal times.
Quantitative easing (QE)
Large-scale asset purchases (Treasuries, mortgage-backed securities) when rates hit zero. Expands the balance sheet to push down long-term yields.
Forward guidance
Communicating future intentions to markets. Shapes expectations so rates "do the work" even before the Fed formally acts.
Interest on Reserve Balances (IORB) β The floor
The rate the Fed pays banks on reserves held at the Fed. Because no bank would lend money overnight for less than it earns by doing nothing, IORB sets a hard floor for the federal funds rate. It replaced the old IOER/IOER split in 2021 and is now the Fed's primary rate-control mechanism β more reliable than open market operations alone.
The rate corridor: how IORB anchors the system
The federal funds rate doesn't float freely β it's bounded in a corridor defined by two administered rates. IORB is the floor; the primary credit rate (discount window) is the ceiling.
Why IORB replaced open market operations as the floor
Before 2008, the Fed kept the federal funds rate on target mainly through open market operations β buying or selling just enough securities to hit the rate. This worked when bank reserves were scarce. After QE flooded banks with excess reserves, that approach broke down: with trillions in reserves, the old mechanics no longer controlled the rate reliably.
IORB solves this by giving every bank a risk-free alternative with a guaranteed return. No bank will lend Fed funds at a rate below IORB, so IORB becomes a gravitational floor regardless of how many reserves are in the system. The Fed now operates an ample-reserves regime β it sets IORB equal to the top of the fed funds target range and lets the floor do the work.
Conventional vs unconventional policy
Conventional
Used in normal times. Rate hikes fight inflation; cuts stimulate growth. Effective as long as rates are above zero. Works through the bank lending channel.
Unconventional
Deployed when rates hit the zero lower bound. Tools include QE, yield curve control, and negative interest rate discussions. Used in 2008 and 2020.
The transmission mechanism
Rate changes affect the economy through several channels simultaneously:
Credit channel
Higher rates β costlier loans β less investment by businesses and less consumption by households.
Exchange rate channel
Higher US rates attract foreign capital β stronger dollar β cheaper imports β lower inflation.
Wealth effect
Higher rates depress asset prices (stocks, housing) β households feel poorer β they spend less.
Rate policy simulator
Set current economic conditions and see how the Fed would likely respond β and what the Taylor Rule suggests.
The Taylor Rule explained
Economist John Taylor (1993) proposed a formula for the "right" interest rate given current conditions. It's widely used as a benchmark β though not a strict rule:
r* = neutral real rate (~2.5%) Β· Ο = current inflation Β· Y β Y* = output gap (actual minus potential GDP)
When inflation is above 2% or the economy is above potential, the formula prescribes higher rates. When below, it prescribes cuts. The Fed uses this alongside many other indicators β it's a guide, not a mandate.
IORB and the rate floor in practice
Whatever target range the FOMC selects, the Fed simultaneously sets IORB equal to the top of that range. This is the floor that prevents the actual fed funds rate from falling below the target. The IORB metric card above always reflects this relationship β it moves in lockstep with whatever target range the simulator implies.
Example: If the FOMC sets a 4.25%β4.50% target range, IORB is set at 4.50%. Banks won't lend reserves overnight below 4.50% because they can earn that risk-free from the Fed itself.
Key historical episodes
The Fed's policies have been shaped by crises. These moments define how the institution thinks and acts today.
Test your knowledge
Six questions covering the core concepts. Read the explanations to reinforce what you've learned.