Why Monetary Accommodation and Weak Starting Positions Magnify the Shock

A fiscal-risk repricing does not arrive in a policy vacuum or on a neutral balance sheet. The question here is how the monetary response and the sovereign's initial risk premium change the path already traced from higher yields to weaker private activity. The BIS evidence points to two amplifiers: accommodation can soften the first months while worsening the later stagflation, and an already-high risk premium can make the same new shock more persistent and more costly.

Accommodation changes the order of costs

“Monetary accommodation” in the BIS study is a measured condition, not a political description. After a positive fiscal-risk shock, the researchers compare the actual policy rate with a forward-looking Taylor-rule benchmark—a rule-based estimate of the rate implied by expected inflation, expected growth, and the previous rate. Policy is classified as accommodative when the actual rate undershoots that benchmark for a sustained period, leaving the real interest rate persistently negative. The comparison is therefore between a policy response that offsets more of the inflationary pressure and one that allows more of it to pass through, not simply between a high and a low nominal rate.

That distinction matters because the policy rate is only one part of the financing environment. A central bank can keep the short rate relatively low while investors push long-term sovereign yields higher. In that case, the apparent support at the short end does not prevent the long end of the curve from repricing the government's future risk. The economy may receive a temporary demand benefit while the borrowing conditions relevant to longer projects and corporate finance become less favourable. The policy stance changes the timing of costs rather than abolishing them.

The BIS comparison shows why the first months can look attractive under accommodation. A lower real rate allows fiscal demand to expand rather than being immediately crowded out by higher borrowing costs. The study finds that the differential effects of passive versus active policy are relatively benign during roughly the first five months. Inflation and inflation expectations rise by similar amounts in both groups at first, while accommodation temporarily limits the increase in long-end yields, term spreads, and equity losses. There is a short-run cushion because the central bank is not fully offsetting the fiscal impulse.

The later comparison is less benign. Real activity begins to decline more sharply after about six months when policy has accommodated the positive fiscal-risk shock. By about one year, headline CPI is estimated to be roughly 1.8 percent higher in the accommodative episodes than in the active-policy comparison. Inflation expectations can be up to 1.5 percentage points higher after two years. The paper reports that these effects persist even after the monetary stance stops being accommodative and the real policy rate rises about twenty months after the shock.

The reason is that accommodation gives other prices more time to adjust. A weaker currency can add imported inflation, and higher expected inflation can become embedded in decisions made before the policy rate eventually catches up. Meanwhile, the long end of the sovereign curve is not permanently controlled by the short rate. Around ten months after the shock, the accommodation differential for the term spread turns positive and remains so; the initial restraint on long-end yields therefore gives way to renewed tightening.