The 2026 Iran energy shock differs categorically from the 2022 episode, when Russia’s invasion of Ukraine led to rerouting of oil and gas supply. The 2026 shock eliminates supply, with a volume loss exceeding 1973-74 and a full energy bill running at two or more times the crude-only estimate. Two features compound the difficulty for the euro area, United States, United Kingdom and Japan: weaker fiscal positions driving term premia higher and a live inflation regime in which tightening is now binding and costly. Narrow fiscal space may therefore force temporary monetary-fiscal coordination: targeted fiscal support to stabilise output, paired with conditional yield anchor operations that prevent financing stress from crowding out that support, while leaving the long end of the curve free to carry the inflation signal. […]