Transmission: How Policy Reaches the Economy

The chain, in order, with the lags attached

The first link is the funding cost: the overnight rate sets the price of short-term wholesale money and of deposits that follow it, and it moves within days. The second is credit conditions — the spread banks and bond investors charge over funding, and the willingness to lend at all, which is only loosely related to the level of the policy rate and moves with perceptions of default risk. The third is asset prices: a higher discount rate lowers the value of long-dated assets, which reduces the collateral behind borrowing and the wealth behind consumption. The fourth is the currency, where the real interest differential moves capital and the exchange rate, which imports disinflation through cheaper imports and reduces demand for exports. Then the second half of the chain, where the lag lives. Businesses respond to higher funding costs by deferring investment, because investment is discretionary and has the longest horizon. Households respond to higher mortgage and card rates by saving more and buying less, with the size of the response depending on the composition of their debt. The labour market responds last: unemployment rises a year or more after the rate path begins to bite, because hiring and firing decisions are slower than price decisions and because firms hold labour through a temporary slowdown to avoid the cost of rehiring. The ordering is what makes policy hard, and it produces the classic error on both sides. Easing too early delivers a growth boost into an economy where inflation has not yet turned, and the bank has to tighten again with its credibility damaged; tightening too long produces a recession that arrives after the committee has declared victory. The reason a committee stops before inflation is at target is not optimism — it is that the policy already in place is still working its way through, and the peak effect on inflation arrives a year after the last rate change. One 200bp move, four lags — Funding costs, days: the overnight rate and floating-rate debt reprice at once · Credit conditions, weeks to months: spreads widen and lending standards tighten — partly independent of policy · Asset prices, immediate but persistent: long-duration valuations fall; collateral and wealth follow ← · Spending and employment, 2–6 quarters: investment first, then consumption, then the labour market · Inflation, 4–8 quarters: the effect on prices arrives after the effect on demand A policy rate defended by a central bank is not the same as a market rate paid by a borrower. The spread between them is where the transmission actually happens or fails, which is why episodes of credit stress can loosen or tighten conditions against the direction of policy.

Financial conditions as the real measure of stance

Because the rate is one input among several, the practical measure of stance is an index of the conditions that actually determine behaviour: short and long rates, credit spreads, the exchange rate, equity prices and lending standards, combined with weights estimated from their historical effect on growth. Those indices exist precisely because the policy rate misleads — most obviously in 2022, when tightening worked through a stronger currency and a mortgage market that repriced quickly, and in other cycles through credit spreads that moved for reasons of their own. The distinction that matters for a decision is between policy-driven and market-driven tightness. A rise in rates because the central bank chose it is a signal about the reaction function, which is information about the future path. A widening spread because credit quality is deteriorating is a market judgement about default, which is information about earnings — and the two can move conditions in the same direction while meaning very different things for a portfolio. A tightening that comes through spreads is a statement about the economy; one that comes through rates is a statement about policy. The third element is refinancing, which converts a level of rates into a cash-flow event. A firm or household that fixed its debt at a low rate is unaffected until the maturity, at which point the entire cumulative move arrives at once. A wall of maturities is therefore a schedule of transmission dates, and the composition of debt — fixed versus floating, short versus long maturity — tells you how fast a given rate level will be felt. Reading the maturity profile is a better forecast of the drag than the rate itself. • Financial conditions indices exist because the policy rate is a poor measure of stance. • Policy-driven tightening is information about the reaction function; spread-driven tightening is information about default. • Refinancing converts a rate level into a dated cash-flow event. • The maturity profile of debt predicts the speed of the drag better than the rate level. The same logic explains why policy works faster in economies with floating-rate mortgages and slower where mortgage rates are fixed for a decade — and why identical rate paths produce very different outcomes across countries.

Why the same rise bites differently: the lock-in effect

The chain in this lesson assumes that a higher policy rate reaches a borrower. That assumption depends on whether the borrower has to borrow again, and the composition of a country’s debt decides how much of the economy is actually in that position. The United States is unusual in the proportion of household mortgage debt that is fixed for thirty years: a household that refinanced at a low fixed rate in 2020 or 2021 is not exposed to the policy rate until it sells the house or takes new debt, so the tightening of 2022 raised the cost of *new* borrowing and left the cost of *existing* borrowing untouched. That is why housing transactions collapsed while household debt-service ratios stayed low — the same shock, transmitted completely to one flow and not at all to a much larger stock. Two refinements follow. First, the rate that matters for a mortgage is not the policy rate but the long-term Treasury yield plus a spread that reflects credit and prepayment risk; the policy rate moves that yield only indirectly. When the Fed raises by 25 basis points and the thirty-year mortgage rate does not move, the transmission has not failed — it was never a direct link. Second, the lock-in cuts the other way on the way down: a household holding a 3% mortgage will not refinance to 5%, so the housing market stays frozen well after policy turns, and turnover recovers on its own schedule rather than on the Fed’s. The same logic applies to firms, and it is what most of the commentary about the maturity wall is about. Corporate debt that was issued long and fixed is insensitive until it matures, so the interest burden a company reports today reflects decisions made years ago. A rise is transmitted at the pace of the refinancing calendar, which is why the corporate credit channel of a tightening cycle can take quarters or years to show up fully, and why the moment a large block of debt comes due is a more important event for that borrower than the FOMC decision itself. One rise, four speeds of transmission — Credit-card and floating-rate debt: Immediate — reprices within a billing cycle · New fixed-rate mortgages: Weeks — through the long yield and lender spread, not the policy rate · Existing fixed-rate household debt: Not until sale or refinancing: the lock-in · Long-dated corporate bonds: At maturity: the refinancing calendar sets the timing ← A practical way to read any tightening cycle: ask which borrowers have to return to the market, and when. The answer locates the pain in time far better than the size of the rate move.

The channels, beyond the policy rate

The chain this lesson has traced is the interest-rate channel: a policy rate moves, market rates follow, borrowing and spending respond, and demand settles at a new level. It is the clearest of the mechanisms, and it is not the only one. Three others operate at the same time, and in some episodes they do most of the work. The **credit channel** runs through the supply of loans rather than their price. Banks do not merely pass on a rate; they decide how much balance-sheet capacity to devote to lending, and that decision depends on their capital, their funding costs and their perception of borrowers’ risk. A tightening that raises funding costs while also weakening borrowers’ balance sheets can contract credit by quantity even if the headline rate has stopped rising. The borrower-balance-sheet half of the same channel works in the other direction: a firm or household with debt that is repriced by a rate move sees its spending change because its net worth changed, not because a loan got more expensive. The **risk-taking channel** is the subtlest and the most consequential for asset prices. A long period of low rates changes what institutions are willing to hold, because the return available on safe assets falls short of the return they have promised. The response is not always more borrowing by households; often it is a search for yield — longer duration, lower credit quality, more leverage in strategies that appear low-risk. That is why the effect of a low-rate regime can show up first in the price of the riskiest assets rather than in the quantity of bank lending, and why the unwinding can arrive as a market event rather than a slowdown in spending. The **exchange-rate channel** closes the loop for an open economy. A tightening that raises domestic rates tends to strengthen the currency, which lowers the price of imports and therefore the inflation rate directly, while making exports dearer and subtracting from growth. In small open economies this channel can be so powerful that it dominates the others, which is part of why the policy discussion in those economies sounds different from the one in a large, relatively closed one. The practical reason to hold all four is that they explain the episodes where the interest-rate channel looked weak. When a tightening produces a sharp asset-price reaction and only a mild slowdown in spending, the risk-taking channel was doing the work; when a tightening produces an abrupt credit contraction, it was the credit channel. Reading which one is binding is what turns “policy is restrictive” from a claim about a rate into a claim about the economy. • The credit channel works on the quantity of lending, not only the price. • The risk-taking channel moves what institutions will hold when safe returns are low. • The exchange-rate channel affects inflation directly through import prices. • Which channel dominates explains why some tightenings bite hard and some barely bite. A useful diagnostic: after a policy move, look at where the response appears first — the currency, credit spreads, risk assets or bank lending. The channel that moves first is the one that will carry most of the effect, and it is not always the one the commentary names.

Sources

• The transmission mechanism and its lagsFederal Reserve education materials; standard monetary-policy transmission literature
• Financial conditions indices and the stance of policyFederal Reserve Bank of Chicago and St. Louis financial-conditions indices
• Credit supply, the bank-lending channel and the refinancing wallBernanke & Gertler (1995), “Inside the Black Box: The Credit Channel of Monetary Policy Transmission”