The simple version

When the price of oil jumps, the first thing that happens is outside anyone's control at a central bank. Fuel costs more. Nobody at the Federal Reserve can produce a barrel, and raising interest rates does not add one.

What happens next is different. A trucking company decides whether to pass its fuel bill into freight rates. A retailer decides whether to pass the freight bill into shelf prices. Workers decide what raise to ask for, and employers decide whether to raise prices to cover it. Those are decisions, and decisions respond to what borrowing costs. That is the part a rate increase can touch, and it is the only part.

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, and its statement says the action will support a timelier return to the Committee's 2 percent goal (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)
• Our reading of the Fed's published projections, not a Fed sentence: in the September Summary of Economic Projections, 12 of 18 participants placed the end-2026 midpoint of the target range at 4.125 percent, 4 at 4.375 percent, and 2 at 3.875 percent, so 16 of 18 sit above the midpoint of the range just set (Federal Reserve, Figure 2 of the projection materials; derived by us)
• The European Central Bank distinguishes three channels for an oil supply shock: direct effects with an immediate link to specific consumer price components, indirect effects that capture the transmission of the shock to consumer prices via the production and distribution chain, and second-round effects, which occur when agents pass on the inflationary impact of the direct and indirect effects to wage and price setting (European Central Bank, Economic Bulletin)
• The Bank for International Settlements states that mainstream monetary theory prescribes an asymmetric response to inflation depending on its drivers, with a strong response to demand-driven inflation and a partial look-through of supply-driven inflation as long as inflation expectations remain firmly anchored, and that when there is a risk that expectations de-anchor, central banks are called upon to react forcefully irrespective of the drivers (Bank for International Settlements, Quarterly Review, December 2024)
• The Federal Reserve states that when households and businesses can reasonably expect inflation to remain low and stable, they are able to make sound decisions regarding saving, borrowing, and investment (Federal Reserve, frequently asked questions on the 2 percent objective)
• The 10-year Treasury par yield was 5.01 percent on Wednesday and 4.94 percent on Thursday (U.S. Treasury Daily Par Yield Curve)

The first round and the rounds after it

Economists who study this split an oil shock into rounds, and the split is the whole article. The European Central Bank's framing is the cleanest available, so it is used here.

The direct effect is the fuel itself: gasoline, diesel, heating oil, the lines in a price index that are literally energy. The indirect effect is the shock traveling through the production and distribution chain into the price of goods that are not energy but had to be made and moved with it. We covered that path when we wrote about diesel as the freight fuel.

The second round is where the shock stops being about oil. In the ECB's words, second-round effects occur when agents pass on the inflationary impact of the direct and indirect effects to wage and price setting. A worker asks for more because groceries cost more. An employer raises prices because payroll costs more. A landlord builds the year's inflation into the renewal. At that point the oil price has become everything else's price, and it can stay there after the oil price itself has come back down.

A central bank cannot reach the first round. It can reach the second, because the second is made of decisions by people and businesses who borrow, and the cost of borrowing is the one price the central bank sets. That is the honest description of what Wednesday's increase can and cannot do, and it takes no position on whether the increase was right.

Why expectations are the whole game

The second round runs on a belief. Whether a worker asks for a raise to cover future inflation, and whether an employer grants it and passes it on, depends on what both of them expect prices to do next year.

That is why a stated numerical inflation target matters more than it looks. We explained what the target is and how it is measured in our article on the inflation target; the short version is that it works by anchoring what people believe future inflation will be. The Federal Reserve's own explanation is that when households and businesses can reasonably expect inflation to remain low and stable, they can make sound decisions about saving, borrowing, and investment.

A shock that leaves that belief in place is a price change. A shock that dislodges it is a materially harder problem, because then the second round feeds itself: prices rise because people expect them to, and people expect them to because they are rising. The BIS puts the policy consequence plainly. As long as expectations remain firmly anchored, the theory says a central bank can partly look through supply-driven inflation; when there is a risk that they de-anchor, it is called upon to react forcefully whatever the driver.

Our earlier coverage of the New York Fed's household survey showed one way that belief is measured. The point here is narrower: the entire justification for touching the second round is that the belief is what the second round is built on.

Economists disagree about this

It would be easy to read the mechanism above as a case for raising rates into every oil shock. It is not, and the people who agree on the mechanism disagree about the conclusion. This section describes the disagreement and resolves nothing.

One position holds that a central bank should look through a supply shock. The BIS review summarizes the theory behind it, citing work by Erceg and coauthors in 2000 and Bodenstein and coauthors in 2008: a supply shock pushes prices and output in opposite directions, its first-round effect reverses on its own, and monetary policy acts with a lag of a year or more, so tightening into it would land after the shock had passed and damage employment for nothing. A 2023 paper for the ECB's central banking forum by Bandera, Barnes, Chavaz, Tenreyro, and von dem Berge states that rationale the same way.

The other position holds that looking through is how the second round gets started. The BIS review cites Reis in 2022 and the same Bandera and coauthors paper for the view that when expectations risk coming loose, a central bank has to respond to the inflation it has regardless of what caused it. The Bandera paper itself concludes that in the presence of second-round effects, looking through energy shocks may no longer be optimal, which is a careful way of saying the first position holds only while the second round stays quiet.

Both positions accept that the tool works on decisions rather than on oil. They disagree about when the decisions have started to move, which is a question about the present state of expectations, and that is exactly the thing nobody can observe directly. This article does not pick a side, and it does not report anyone's remarks about which side the Committee is on.

The Real Cost lens on a supply shock

The distribution of the two rounds across a household is uneven, and the unevenness is the point. No figure below is computed; each is a description of where an effect lands.

• The first round reaches a household at the pump and, with a lag, inside the price of everything that was shipped, and no interest rate changes that
• The second round reaches a household through its pay, its rent, and the prices of services that have nothing to do with oil, and that is the round a rate increase is aimed at
• A rate increase reaches a household through borrowing costs, so it lands hardest on anyone financing a home, a vehicle, or a balance, who is also paying the first round at the pump
• None of that is a reason to act on anything, and this article makes no claim about what the Committee should do next

That is the honest picture. The instrument is aimed at the round made of decisions, the people who feel the shock and the people who feel the response overlap without being identical, and whether the aim was right is the disagreement above.

What this means

When a rate decision arrives alongside energy-driven inflation, the question that clarifies it is which round the pressure has reached. If it is still in fuel and freight, the tool is pointed past it. If it has reached wages, rents, and service prices, the tool is pointed at it. The inflation report's split between energy and everything else is where that answer lives.

The broader idea is that every instrument has a reach, and knowing what a tool operates on, and therefore what it cannot touch, is most of understanding what an institution can actually deliver. A central bank cannot deliver oil. It can try to deliver a stable belief about next year's prices, and that is a smaller and a more important thing than it sounds.

What this is NOT

This is not a position on whether the September 16 rate increase was correct or on whether another one should follow, and the projections reading in The numbers is our own count from the Fed's published table, not a Fed statement of intent. This is not a prediction of where inflation or rates go. No official is quoted, paraphrased, or characterized, and no press conference is reported: second-round effects are a standard concept in monetary economics, described here from institutional research, not from anyone's remarks. This is not a claim that inflation is under control or out of control, and it does not resolve the disagreement it describes. This is not a position on energy policy, on any conflict, or on trade. This is not advice about borrowing, saving, or any financial decision, and it is not advice about any security or fund. This is not investment or financial advice of any kind.

Sources

• Federal Reserve, FOMC statement, September 16, 2026 (the target range, the vote, and the 2 percent goal sentence): https://www.federalreserve.gov/newsevents/pressreleases/monetary20260916a.htm
• Federal Reserve, Summary of Economic Projections, September 2026, projection materials including Figure 2 (the end-2026 distribution we counted): https://www.federalreserve.gov/monetarypolicy/fomcprojtabl20260916.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, Why does the Federal Reserve aim for inflation of 2 percent over the longer run? (expectations and sound decisions): https://www.federalreserve.gov/faqs/economy_14400.htm
• European Central Bank, Economic Bulletin, Issue 5, 2022, box on wage share dynamics and second-round effects on inflation after energy price surges (direct, indirect, and second-round effects defined): https://www.ecb.europa.eu/press/economic-bulletin/focus/2022/html/ecb.ebbox202205_02~e203142329.en.html
• Bank for International Settlements, Quarterly Review, December 2024, Targeted Taylor rules: monetary policy responses to demand- and supply-driven inflation (the look-through prescription and its limit, with the works it cites): https://www.bis.org/publ/qtrpdf/r_qt2412d.htm
• Bandera, Barnes, Chavaz, Tenreyro, and von dem Berge, Monetary policy in the face of supply shocks: the role of inflation expectations, ECB Forum on Central Banking, 2023: https://www.ecb.europa.eu/press/conferences/ecbforum/shared/pdf/2023/Tenreyro_paper.pdf
• 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