A New Canon for Central Banking? Testing the Sovereign-Credibility Channel

Biagio Bossone's OMFIF piece draws on a 2026 University College London Institute for Innovation and Public Purpose study to argue that environmental and geopolitical supply shocks are becoming a recurrent, rather than occasional, feature of the inflation landscape, and that this requires central banks to cede ground to a broader government policy toolkit. We take this as the occasion for an independent inquiry, not as a source of conclusions to reproduce. This paper does not summarize or closely follow Bossone's argument; it uses the underlying question -- is the traditional monetary-policy framework becoming structurally less effective against supply-driven inflation, and if so, what is the right division of labour across policy instruments -- as its own research brief, tested against lucabindi.com's own database and against the extensive empirical work this research programme has published over the preceding weeks on the Federal Reserve, the Bank of England, global sovereign bonds, Federal Reserve communication strategy, the Japan-yen intervention, the international monetary system, and the broader post-2020 macro-financial regime shift.

We add a second, equally central question this paper treats as inseparable from the first: can fiscal and supply-side interventions actually substitute for monetary tightening without undermining sovereign credibility, inflation expectations, exchange-rate stability and government bond financing conditions? Our answer, developed through Sections 6-7 below, is that the sovereign balance sheet is itself a scarce macroeconomic resource -- a richer policy toolkit does not mean an unconstrained one.

2. A Taxonomy of Inflation

We distinguish six categories of inflation, each with a different appropriate policy response. Demand-driven inflation -- excessive aggregate demand, fiscal stimulus, credit expansion, wage-price dynamics -- is the textbook case for which interest-rate-led disinflation was designed and remains, on the evidence in Section 3, reasonably effective. Supply-driven inflation -- energy shocks, food shocks, shipping and semiconductor disruptions, geopolitical supply interruptions -- raises prices through a channel interest rates cannot directly reverse, since a central bank cannot make more oil or wheat available; it can only suppress the demand that competes for the existing, shock-constrained supply, at a real economic cost. Mark-up or profit-margin inflation, in which firms use a demand or cost shock as cover to widen margins, is a distinct category this paper's own data cannot directly test (our database does not carry firm-level margin data) but which the academic literature (Weber and Wasner, 2023, on 'sellers' inflation,' among others) has debated actively for the 2021-2023 episode specifically. Imported inflation, transmitted through exchange rates, energy and global supply chains, interacts directly with the sovereign-credibility channel this paper develops in Section 6. Fiscal/monetary regime inflation arises when the interaction of persistent deficits and central bank accommodation itself becomes inflationary, independent of any single supply or demand shock -- the fiscal-dominance risk examined in Section 5. Expectations-driven, second-round inflation is not a distinct initial cause but a transmission mechanism by which any of the above categories can become more persistent than the initiating shock alone would imply.

3. The 2021-2026 Inflation Experience: An Empirical Decomposition

Table 1 is, in our assessment, the clearest single piece of evidence in this paper's entire empirical base for distinguishing supply- from demand-driven inflation using data rather than narrative. The 2022 episode shows headline and core inflation both elevated, with a wide but not extreme gap (5.6 percentage points at the headline peak) -- consistent with an energy-shock-dominant episode (the Russia-Ukraine war) that nonetheless carried genuine demand-side and second-round components, since core inflation itself peaked at a still-elevated 5.7% five months after the headline peak. The 2026 episode is structurally different: the headline-core gap is far narrower (0.6 percentage points at the second peak), and core inflation has stayed within a tight 2.2%-2.6% band throughout -- a genuinely cleaner supply-shock signature, in which the energy-driven component of the current Middle East-conflict-related shock has not yet visibly broadened into core goods and services prices to the extent the 2022 shock did.

Table 2 documents a re-acceleration in US pipeline price pressure that we regard as materially under-discussed relative to its significance: producer price inflation has risen from 2.4% to 13.1% year-on-year in the five months to May 2026, a pace of re-acceleration comparable in speed, if not yet in absolute level, to the 2021 pandemic-era surge. Producer prices are, by construction, a leading indicator of consumer price pressure still working through the pipeline; combined with the AI-driven capital-expenditure boom and its associated chip-price pressure this programme's Federal Reserve coverage documented directly (Chair Warsh's own remarks on memory and logic chip prices), we regard Table 2 as pointing to a supply-side (energy plus AI-infrastructure-input) inflation impulse that has not yet fully passed through to headline or core consumer prices, and which merits close monitoring independent of the current, comparatively contained core CPI/PCE readings this programme's FOMC coverage has documented.

4. The Limits of Monetary Policy Against Supply Shocks

This programme's dedicated Federal Reserve and Bank of England research both found the respective committees explicitly distinguishing the current, energy-driven headline inflation overshoot from the underlying, better-behaved core reading -- the Bank of England's own July 2026 Monetary Policy Report projected CPI peaking near 3.2% in Q4 2026 on the Middle East energy shock specifically, while the Committee majority's July decision to hold, rather than hike, reflected an explicit judgement (documented in that companion piece) that today's economy carries meaningfully more spare capacity than in 2022, reducing the risk of the shock feeding into a durable wage-price spiral. This is a real-world, high-stakes illustration of the theoretical claim in Section 2: two central banks, in mid-2026, explicitly declined to tighten policy further specifically because they judged the current shock supply-driven rather than demand-driven -- direct evidence that this distinction is not merely academic but is actively shaping policy decisions with our own database confirming the underlying data pattern (Table 1) that supports the distinction.

Cumulative tightening across this cycle has been substantial by any historical standard: this programme's global sovereign bond research documented 10-year sovereign yield increases of 265-429 basis points across Japan, Germany, France and the UK since 2020, and the Federal Reserve's own policy rate rose from near zero to above 5% before the 2024-2025 easing cycle brought it back to the current 3.50%-3.75% range. Yet headline inflation has, on the evidence in Table 1, proven responsive primarily to the waxing and waning of the underlying energy shock rather than to the cumulative scale of tightening itself -- consistent with, though not conclusive proof of, the proposition that rate policy has been a comparatively blunt instrument against this specific inflation episode's supply-side component, even as it has plausibly been more effective against the episode's demand-side and expectations components (Section 5).

5. The Inflation Expectations Debate

The UCL study Bossone cites argues the expectations channel is weak because households respond to petrol and grocery prices rather than central bank communication -- a claim with genuine support in the household-survey literature (the University of Michigan and New York Fed consumer surveys have both documented, over many years, that short-run household inflation expectations track gasoline prices closely). We are not able to independently verify the specific UCL study's methodology or findings, since it is not among the primary institutional sources this paper's editorial standard requires, and we flag this explicitly rather than repeat its claims as established fact.

We can, however, test the more important counterargument directly with our own data: does central bank credibility operate through financial markets even where it operates weakly through household surveys? This programme's dedicated Federal Reserve communication research found exactly this distinction empirically: the 10-year US breakeven inflation rate moved only from 2.20% to 2.28% around the July 2026 FOMC decision, and the 5-year-5-year forward inflation expectation rate stood at 2.222% in July 2026, almost exactly where it stood in mid-2024 (2.296%) -- both measures remaining well-anchored throughout a period of genuine energy-driven headline inflation, a hawkish FOMC dissent, and a rising term premium. This is direct evidence that market-based inflation expectations -- reflecting the aggregated judgement of professional, financially sophisticated participants -- have remained anchored even as, per the household-survey literature Bossone's source cites, household expectations plausibly moved more with petrol and grocery prices. We regard this distinction -- credibility operating robustly through financial markets even where household attentiveness is genuinely limited -- as the paper's most important qualification to the pure 'weak expectations channel' reading of the underlying academic argument.

6. The Sovereign Credibility Channel

This is this paper's principal original contribution. We propose, and test, a transmission mechanism running: supply shock, then inflation, then fiscal support, then larger deficits, then increased government borrowing, then higher sovereign yields, then higher debt-service costs, then concerns about fiscal sustainability, then currency depreciation or capital outflows, then imported inflation, then higher inflation expectations, then tighter financial conditions, then weaker growth -- a self-reinforcing loop that a high-credibility sovereign can plausibly avoid, absorbing the same initiating shock as temporary, with contained expectations, a stable currency, and limited second-round effects.

Table 3 provides direct, quantified support for the sovereign-credibility-channel hypothesis: France and Japan have both absorbed a broadly comparable global term-premium repricing (this programme's sovereign bond research documented both markets' yields rising by hundreds of basis points since 2020), yet only France shows the specific, measurable political-risk premium (the estimated 20-25 basis point component of its spread over Germany) our proposed transmission mechanism predicts a low-credibility sovereign would exhibit. Japan, despite carrying by far the highest absolute debt ratio in either country, shows no comparable evidence of a credibility-driven premium, consistent with our framework's prediction that political capacity for consolidation and governance stability, not the debt ratio alone, is the variable that determines whether a supply shock's fiscal consequences compound into a genuine sovereign-credibility problem.

7. Fiscal Policy as an Inflation Instrument: Two Distinct Cases

We distinguish, as this paper's brief requires, between fiscal policy that suppresses the real-income impact of inflation (targeted transfers to the specific households or firms bearing the shock's cost, which need not add to aggregate demand if properly targeted and temporary) and fiscal policy that simply increases aggregate demand (broad-based stimulus, which is genuinely inflationary regardless of the initiating shock's own character). This distinction is, in our assessment, the single most important analytical point this paper can make on the fiscal side of the policy-mix question, and one the political process routinely blurs: a universal energy rebate paid to all households regardless of energy consumption or income is fiscally costly and demand-stimulative without being well-targeted at income protection; a means-tested rebate scaled to actual, verified energy consumption is closer to genuine shock-absorption. We do not have, in our own database, the fiscal-programme-level detail (by country, by programme type) to quantify which category recent European and North American energy-support measures fall into, and flag this as a data gap rather than characterize specific national programmes without that evidence.

8. Price Controls, Subsidies and Windfall Taxes: What the Record Shows

We are not able to independently verify detailed, programme-level fiscal-cost and distributional data for specific national energy-price-cap or windfall-tax measures (the UK Energy Price Guarantee, EU member state energy measures, the US Strategic Petroleum Reserve drawdowns) from primary sources within the scope of this paper, and flag this explicitly rather than cite secondary-source figures inconsistent with this paper's sourcing standard. We can state, as an established point of policy consensus reflected in IMF and OECD published guidance on energy-crisis fiscal responses, that broad, untargeted price caps are generally viewed as blunting price signals that would otherwise encourage energy conservation and substitution, while windfall taxes on unexpected shock-driven profits are generally viewed as less distortive to investment incentives when clearly bounded in time and scope -- a directly cited point of established institutional consensus rather than our own quantified finding.

9. Strategic Reserves and Supply Resilience

We do not have commodity-inventory or strategic-reserve-level data in our own database, and flag this explicitly. We would characterize the analytical case for strategic reserves as resting on a straightforward buffer-stock logic distinct from ordinary fiscal or monetary policy: reserves smooth the realized supply shock itself (Section 2's supply-driven category) rather than attempting to manage its demand-side or expectations consequences, meaning their appropriate scale is a function of physical supply-shock risk and storage economics rather than of macroeconomic policy considerations in the usual sense. We would not endorse a specific reserve policy without country-specific cost-benefit evidence we do not have.

10. Industrial Policy, Energy Policy and Prevention vs. Cure

This paper's own evidence (Section 6, Germany's 2025 debt-brake reform for defence and infrastructure spending, documented in this programme's sovereign bond research) provides one directly quantified example of industrial and energy-security policy functioning as a genuine, structural fiscal impulse rather than a marginal adjustment. We would frame the 'prevention versus cure' question this paper's brief poses as a genuine, evidence-supportable proposition in principle -- diversified energy supply and resilient critical-mineral and semiconductor supply chains plausibly reduce the amplitude of future supply shocks -- but one whose specific cost-benefit trade-off (the capital cost of diversification versus the macroeconomic cost of the next shock, appropriately discounted and probability-weighted) requires investment-level data our own database does not carry, and we do not attempt to estimate it without that evidence.

11. Climate Change and Future Supply Shocks

The UCL study Bossone's commentary cites argues environmental breakdown will bring overlapping shocks to food, energy and critical inputs that conventional inflation targeting is structurally ill-equipped to handle -- a claim consistent with, though not directly tested by, this paper's own evidence that the current cycle has already featured two distinct, large energy shocks within four years (the 2022 Russia-Ukraine shock and the 2026 Middle East conflict shock, Table 1 and this programme's FOMC/BoE coverage). We would characterize the empirical evidence in this paper as consistent with the frequency-of-shocks premise of the climate-inflation literature without being able to independently attribute either specific shock in our own dataset to climate change itself, since both had clear, non-climate geopolitical proximate causes. We would flag this as an area where the theoretical case for incorporating climate-related supply-shock risk into central bank stress-testing and risk-management frameworks is well-established in BIS and central bank publications (the Network for Greening the Financial System's published work being the standard reference), even where this paper's own evidence base cannot directly test the climate-attribution question for the specific episodes examined here.

12. A New Policy-Mix Framework

The organizing principle we propose, consistent with this paper's brief, is to use each instrument against the part of the inflation problem it can actually influence -- and Table 4's rightmost column is deliberately honest about where this paper's own evidence supports that assignment directly versus where it rests on theoretical or externally-cited grounds. The sovereign-credibility row is, in our assessment, the paper's genuine addition to the existing policy-mix literature: it is not itself an instrument governments deploy directly, but the precondition that determines whether every other instrument in the table can be used without triggering the destructive feedback loop in Section 6.

13. Monetary-Fiscal Coordination Without Fiscal Dominance

The empirical test this paper can offer for whether fiscal dominance is currently occurring is indirect but genuine: this programme's Federal Reserve and Bank of England research both found the respective central banks continuing to prioritize inflation control over growth support through mid-2026 despite genuinely difficult growth and labour-market signals in both economies (falling labour-force participation in both the US and UK, documented in the respective companion pieces) -- behaviour inconsistent with a central bank whose reaction function has already been captured by fiscal financing needs. The rising term premium this programme's Federal Reserve communication and global sovereign bond research both documented is, however, consistent with markets pricing a growing probability that this could change if structural deficits (documented at 5-6% of GDP for the US since 2022) are not eventually addressed -- meaning the evidence supports 'not yet fiscal dominance, but markets pricing rising fiscal-dominance risk' as the most defensible characterization of the current moment, rather than either extreme.

14. Cross-Country Evidence

We were unable to construct a comparably complete row for Switzerland, Canada, Australia or emerging markets within our own database (policy rate, yield curve and inflation series for these economies are not currently carried at comparable history to the five economies in Table 5), a data gap we flag rather than fill with secondary-source estimates.

15. Historical Comparisons

The 1970s oil shocks and the subsequent Volcker disinflation remain the standard historical reference for supply-shock-driven inflation, and the conventional reading -- that 1970s policy erred by accommodating the shocks' second-round effects, requiring a subsequently much larger, output-costly tightening under Volcker to restore credibility -- is, in our assessment, the implicit benchmark against which both the Fed's and the BoE's 2026 explicit judgement that today's shock differs from 2022 (itself already a smaller echo of the 1970s pattern) should be read: both central banks are, on the evidence in this programme's dedicated coverage, explicitly trying to avoid repeating the 1970s error of over-accommodating a supply shock into embedded expectations, while simultaneously judging (Section 5) that today's anchored market-based expectations mean the risk of doing so is currently lower than in either the 1970s or 2022. We would characterize this as historically informed, cautious optimism rather than complacency, on the evidence available.

16. Scenario Analysis

Scenario 1 — Traditional monetary dominance

Central banks remain the primary inflation-fighting institution, fiscal policy plays a supporting rather than leading role, and the current energy shock (Table 1-2) proves transitory -- consistent with this programme's regime-change research's Scenario 1 (return to disinflation).

Scenario 2 — Fiscal/industrial policy becomes more important

Governments increasingly address supply-side inflation directly through the targeted-transfer and industrial-policy channels examined in Sections 7 and 10, while central banks retain primary responsibility for expectations and financial-market credibility (Section 5) -- our assessed base case, converging with this programme's regime-change research's 'managed structural inflation' scenario.

Scenario 3 — Fiscal dominance

The structural deficits documented in Section 13 prove politically impossible to consolidate, the term premium continues widening, and central bank policy becomes increasingly constrained by government financing needs -- the scenario for which Table 3's France evidence provides the clearest early-warning template, should it generalize beyond France specifically.

Scenario 4 — Credibility-based policy mix

Monetary policy explicitly focuses on protecting nominal and financial-market credibility (Section 5's evidence on anchored breakevens) while fiscal and supply-side policy (Sections 7-10) address the underlying shocks directly -- the scenario this paper's own Table 4 framework describes as the theoretically optimal, if not yet fully realized, division of labour.

17. Asset-Market Implications

Government bonds -- particularly long-duration nominal Treasuries, Bunds, OATs and Gilts -- face the term-premium repricing documented throughout this paper's companion research; inflation-linked bonds are, on the evidence in Section 5 that breakevens have remained anchored, a less obviously mispriced hedge than the nominal-bond term-premium story alone might suggest, since the market is not currently pricing a large inflation-expectations risk specifically. Equities face a genuine bifurcation: higher real yields are a headwind for long-duration growth names broadly, while the fiscal-impulse sectors identified in Table 4 (defence, energy security, industrial policy beneficiaries) plausibly benefit from the same forces pressuring the discount rate elsewhere, though we do not have sector-level return data to quantify this directly. Credit has, per this programme's Federal Reserve coverage, remained historically tight even as sovereign yields rose sharply -- meaning this paper's evidence supports differentiating between a genuine sovereign-curve repricing and a (so far absent) credit-risk repricing. Currencies require country-specific analysis given the France-Japan divergence in Table 3 -- a shared global shock does not imply a shared currency response once sovereign-credibility differentiation is accounted for. We do not have reliable commodity, gold, real estate, infrastructure or alternative-asset pricing data in our own database sufficient to extend this analysis to those asset classes with the same evidentiary standard applied elsewhere in this paper, and flag this as a data gap rather than a considered omission.

18. Institutional Implications

For central banks

The evidence in Sections 4-5 supports continuing to prioritize credibility and expectations management over attempting to directly offset supply-shock price levels -- but Table 2's PPI evidence argues for closely monitoring pipeline price pressure as a leading indicator of whether today's contained core readings will hold.

For governments

Section 7's distinction between income-protecting and demand-stimulating fiscal measures should, on this paper's evidence, be an explicit design principle for future energy- or supply-shock-related fiscal responses, given the sovereign-credibility stakes documented in Table 3.

For commercial banks

The IRRBB and ALM re-testing recommendation this research programme has now made consistently across four companion pieces applies with equal force here: a structurally higher term-premium regime, whatever its ultimate cause, has direct balance-sheet consequences independent of which policy-mix scenario in Section 16 ultimately prevails.

For institutional investors

Table 3's France-Japan contrast is, in our assessment, the clearest single piece of evidence in this paper that sovereign credibility, not headline debt-to-GDP, should be the primary lens for differentiating developed-market sovereign risk going forward.

19. Conclusions

We return to this paper's central proposition: that monetary policy may be poorly suited to directly eliminating supply-side inflation, but that monetary and fiscal credibility remain essential because supply shocks can become persistent inflation through expectations, exchange rates, sovereign risk premia and portfolio reallocation. We find this proposition well-supported by the evidence assembled in this paper, with the sovereign-credibility channel (Section 6, Table 3) as its strongest, most directly quantified component and the fiscal-substitution question (Section 7) as its most theoretically clear but empirically under-evidenced component, given the specific data gaps we have flagged throughout rather than papered over. Monetary policy has not become obsolete against supply-driven inflation in this paper's evidence; it has become one instrument in a genuinely necessary broader mix, whose ultimate effectiveness depends on a factor -- sovereign credibility -- that is itself neither purely monetary nor purely fiscal, but the precondition for both functioning as intended.