# Sofia Carollo and Natalie Burr argue in Bank Underground that the yield curve matters [Canonical reading](https://escapemeridian.com/readings/sofia-carollo-and-natalie-burr-argue-in-bank-underground-that-436ea2a4) Published September 3, 2026, Sofia Carollo and Natalie Burr argue in Bank Underground that monetary policy affects the economy through more than the policy rate: households and firms face borrowing costs across different time horizons. They separate announcement-related yield movements into a “level” surprise, which shifts yields broadly, and a “slope” surprise, which changes the curve’s steepness. In their analysis, a level shock affects CPI more than a slope shock does; the slope shock boosts GDP while leaving CPI broadly unchanged. The authors say the two types of shock are not interchangeable because changes at different maturities transmit with different strength and timing, even when they imply a similar average change in yields. They conclude that policymakers should attend to how yield changes are distributed across maturities when judging monetary transmission, while noting that they cannot precisely control the entire curve. The estimates use a linear framework, and the authors caution that monetary policy transmission may be asymmetric: easing and tightening may have different effects. Their analysis does not address whether particular maturities matter more. Headline and summary by Escape Meridian, prepared by Luna from the attributed source. A source check is not independent confirmation of the source’s claims. ## Original source Bank of England · Article Original source date: Sep 3, 2026 (2026-09-03T08:00:00.000Z). Date basis: Date supplied by the publisher’s feed. Added to Escape Meridian: 2026-11-06T04:58:24.099Z. First observed: 2026-10-23T18:49:38.607Z. Retrieved: 2026-10-23T18:51:46.134Z. - [Monetary policy transmission: it’s all in the curve](https://bankunderground.co.uk/2026/09/03/monetary-policy-transmission-its-all-in-the-curve/) ## Limits Text as retrieved on October 23, 2026; originally published September 3, 2026. The authors describe their level and slope factors as empirical approximations, not structurally modelled shocks. The authors say their analysis does not address whether particular maturities matter more. ## Open question How would the estimated differences between level and slope shocks change if monetary policy transmission were asymmetric, as the authors note it may be? ## Source-stated Carollo and Burr argue that monetary policy transmission should be assessed across the yield curve, not only through the policy rate. > Measuring the effects of monetary policy therefore means looking at the whole curve, not just one rate - [Supporting source](https://bankunderground.co.uk/2026/09/03/monetary-policy-transmission-its-all-in-the-curve/) ## Source-stated The authors report that a level surprise affects CPI more than a slope surprise does. > We find that a level surprise affects CPI inflation more than a slope surprise does - [Supporting source](https://bankunderground.co.uk/2026/09/03/monetary-policy-transmission-its-all-in-the-curve/) ## Source-stated In the authors’ estimates, a positive slope shock boosts GDP while leaving CPI broadly unchanged. > A positive slope shock, ie, a 25-basis-point on-impact fall in short‑term yields, boosts GDP while leaving CPI broadly unchanged - [Supporting source](https://bankunderground.co.uk/2026/09/03/monetary-policy-transmission-its-all-in-the-curve/) ## Source-stated Carollo and Burr conclude that policymakers should consider how yield changes are distributed across maturities when assessing monetary transmission. > they should be attentive not just to an average change in yields, but to the configuration of those changes across maturities - [Supporting source](https://bankunderground.co.uk/2026/09/03/monetary-policy-transmission-its-all-in-the-curve/) ## Source-stated The authors say their work does not answer whether particular maturities matter more. > It is not that particular maturities ‘matter more’ (a separate question we do not cover in the post). - [Supporting source](https://bankunderground.co.uk/2026/09/03/monetary-policy-transmission-its-all-in-the-curve/) ## Source-stated Carollo and Burr note that monetary policy transmission may be asymmetric, with easing and tightening having different macroeconomic effects. > monetary policy transmission may be asymmetric, with easing and tightening having different macroeconomic effects - [Supporting source](https://bankunderground.co.uk/2026/09/03/monetary-policy-transmission-its-all-in-the-curve/) ## Source and contributor context Bank of England · Publisher The publisher is identified here. No individual author has been inferred. ## Source media Media retrieval status: unchecked. ## Terms and references Reference context selected by Escape Meridian; separate from source evidence. Entity mentions do not establish authorship, involvement or endorsement. ## Time horizon METR's measure of AI agents' ability: the length of task, timed by how long skilled people take, that an agent completes at a set success rate. - [Definition reference](https://metr.org/blog/2025-03-19-measuring-ai-ability-to-complete-long-tasks/) ## Consumer price index A measure of the average change over time in the prices consumers pay for a representative basket of goods and services; it measures inflation as consumers experience it in day-to-day living expenses. - [Definition reference](https://www.bls.gov/cpi/questions-and-answers.htm) ## Editorial provenance Version 1. Publication ID: b42cc37d-296c-bf6e-4e16-4010bed083fa. Prepared by openai/gpt-6-luna; grounding review by anthropic/claude-opus-5.5. Source check: uncertain by anthropic/claude-opus-5.5 on 2026-11-06T04:54:00.440Z. This checks fidelity to the source, not whether its claims are independently true. Editorial selection: accept; reasons: bridge\_admitted\_by\_model. Observation: d66920d612f1aa7d83ecb86dacd98bc1276c1d1f0f62f40bc2821c3924403300. Source text hash: 5a61bd5aed03397ffd21e74b2f2a0e9b30efe5bb9a6929f6050737d883840284. ## Revision and source-check history ### Version 1 — 2026-11-06T04:58:24.099Z Published September 3, 2026, Sofia Carollo and Natalie Burr argue in Bank Underground that monetary policy affects the economy through more than the policy rate: households and firms face borrowing costs across different time horizons. They separate announcement-related yield movements into a “level” surprise, which shifts yields broadly, and a “slope” surprise, which changes the curve’s steepness. In their analysis, a level shock affects CPI more than a slope shock does; the slope shock boosts GDP while leaving CPI broadly unchanged. The authors say the two types of shock are not interchangeable because changes at different maturities transmit with different strength and timing, even when they imply a similar average change in yields. They conclude that policymakers should attend to how yield changes are distributed across maturities when judging monetary transmission, while noting that they cannot precisely control the entire curve. The estimates use a linear framework, and the authors caution that monetary policy transmission may be asymmetric: easing and tightening may have different effects. Their analysis does not address whether particular maturities matter more. ## Original source Bank of England · Article Original source date: Sep 3, 2026 (2026-09-03T08:00:00.000Z). Date basis: Date supplied by the publisher’s feed. Added to Escape Meridian: 2026-11-06T04:58:24.099Z. First observed: 2026-10-23T18:49:38.607Z. Retrieved: 2026-10-23T18:51:46.134Z. - [Monetary policy transmission: it’s all in the curve](https://bankunderground.co.uk/2026/09/03/monetary-policy-transmission-its-all-in-the-curve/) ## Limits Text as retrieved on October 23, 2026; originally published September 3, 2026. The authors describe their level and slope factors as empirical approximations, not structurally modelled shocks. The authors say their analysis does not address whether particular maturities matter more. ## Open question How would the estimated differences between level and slope shocks change if monetary policy transmission were asymmetric, as the authors note it may be? ## Source-stated Carollo and Burr argue that monetary policy transmission should be assessed across the yield curve, not only through the policy rate. > Measuring the effects of monetary policy therefore means looking at the whole curve, not just one rate - [Supporting source](https://bankunderground.co.uk/2026/09/03/monetary-policy-transmission-its-all-in-the-curve/) ## Source-stated The authors report that a level surprise affects CPI more than a slope surprise does. > We find that a level surprise affects CPI inflation more than a slope surprise does - [Supporting source](https://bankunderground.co.uk/2026/09/03/monetary-policy-transmission-its-all-in-the-curve/) ## Source-stated In the authors’ estimates, a positive slope shock boosts GDP while leaving CPI broadly unchanged. > A positive slope shock, ie, a 25-basis-point on-impact fall in short‑term yields, boosts GDP while leaving CPI broadly unchanged - [Supporting source](https://bankunderground.co.uk/2026/09/03/monetary-policy-transmission-its-all-in-the-curve/) ## Source-stated Carollo and Burr conclude that policymakers should consider how yield changes are distributed across maturities when assessing monetary transmission. > they should be attentive not just to an average change in yields, but to the configuration of those changes across maturities - [Supporting source](https://bankunderground.co.uk/2026/09/03/monetary-policy-transmission-its-all-in-the-curve/) ## Source-stated The authors say their work does not answer whether particular maturities matter more. > It is not that particular maturities ‘matter more’ (a separate question we do not cover in the post). - [Supporting source](https://bankunderground.co.uk/2026/09/03/monetary-policy-transmission-its-all-in-the-curve/) ## Source-stated Carollo and Burr note that monetary policy transmission may be asymmetric, with easing and tightening having different macroeconomic effects. > monetary policy transmission may be asymmetric, with easing and tightening having different macroeconomic effects - [Supporting source](https://bankunderground.co.uk/2026/09/03/monetary-policy-transmission-its-all-in-the-curve/) ## Source and contributor context Bank of England · Publisher The publisher is identified here. No individual author has been inferred. ## Source media Media retrieval status: unchecked. ## Terms and references Reference context selected by Escape Meridian; separate from source evidence. Entity mentions do not establish authorship, involvement or endorsement. ## Time horizon METR's measure of AI agents' ability: the length of task, timed by how long skilled people take, that an agent completes at a set success rate. - [Definition reference](https://metr.org/blog/2025-03-19-measuring-ai-ability-to-complete-long-tasks/) ## Consumer price index A measure of the average change over time in the prices consumers pay for a representative basket of goods and services; it measures inflation as consumers experience it in day-to-day living expenses. - [Definition reference](https://www.bls.gov/cpi/questions-and-answers.htm) ## Editorial provenance Version 1. Publication ID: b42cc37d-296c-bf6e-4e16-4010bed083fa. Prepared by openai/gpt-6-luna; grounding review by anthropic/claude-opus-5.5. Source check: uncertain by anthropic/claude-opus-5.5 on 2026-11-06T04:54:00.440Z. This checks fidelity to the source, not whether its claims are independently true. Editorial selection: accept; reasons: bridge\_admitted\_by\_model. Observation: d66920d612f1aa7d83ecb86dacd98bc1276c1d1f0f62f40bc2821c3924403300. Source text hash: 5a61bd5aed03397ffd21e74b2f2a0e9b30efe5bb9a6929f6050737d883840284. ### uncertain — 2026-11-06T04:54:00.440Z — anthropic/claude-opus-5.5 Publication: b42cc37d-296c-bf6e-4e16-4010bed083fa attribution — pass: The reading correctly attributes the post to Sofia Carollo and Natalie Burr on Bank Underground, the Bank of England staff blog. It presents the findings as the authors' analysis, not as Bank policy, which matches the source's disclaimer. > The views expressed here are those of the authors, and are not necessarily those of the Bank of England, or its policy committees. summary — uncertain: The summary is faithful. However, the central terms 'yield curve', 'maturities' and 'monetary transmission' are never explained in plain language, and no definitions are supplied for them. The reading also links 'time horizons' to a definition of METR's AI-agent task measure, which is wrong in this bond-market context and would mislead a general reader. Smallest repair: define the yield curve as borrowing rates across loan lengths and drop the METR tooltip. The summary should also say it is a positive (steepening) slope shock that boosts GDP. > households and firms borrow at varying time horizons date — pass: The displayed date, September 3, 2026, matches the UTC day of originalPublished and the page dateline (03/09/2026). The page was edited after publication, but the reading relies only on the main body text, which is plainly original. There is no hindsight framing and no forecast presented as an outcome. The kind is publisher-page, so no archive disclosure is required. > 03/09/202602/09/2026 support — pass: Every claim matches the source: the whole-curve framing, level versus slope effects on CPI, the GDP effect of a positive slope shock, the policy conclusion, the asymmetry caveat, and the stated scope limit. The editedAfterPublication flag does not affect these claims, because the cited passages are plainly part of the original article body. The question about asymmetry follows from the authors' own caveat. > even when they imply a similar change in the average level of yields media — pass: No media was selected, and no verified media candidates were supplied, so no media was invented or misidentified. ## Recorded references Explicit citations in public readings and public file attachments to this reading. Shared topics are not citations. Other artifact types need an explicit reference adapter. No public references recorded here yet. [Reference data (JSON)](/readings/436ea2a4f5c2d4ee697ddb0fde3d458e35289401824a012c06aa58b3ac577929/references.json) ## Corrections and challenges [Send a correction or an opposing source](https://escapemeridian.com/corrections/) [JSON record](https://escapemeridian.com/readings/sofia-carollo-and-natalie-burr-argue-in-bank-underground-that-436ea2a4.json)