政策制定者对冲击的回应能力正全面下降。文章指出，过去三十年左右，大型央行与政府往往在市场抛售时超越「只容忍下跌」的界线，透过口头干预与政策工具抚平股市震荡，即使2018年第四季那样市场管道运作正常、实体经济也不差的情况亦然。这种做法强化了投资者对「政策支撑」的信念，让逢低买入成为主导策略，并在伊朗战争冲击后迅速反弹的全球股市中再次得到验证。

但当前宏观环境已不再支持这种安全网。高通膨、长期较高利率、高债务与全球经济结构转变，正同时压缩货币与财政空间。美国最新数据显示，整体与核心CPI都高于共识预期；更值得警惕的是，4月PPI月增率按年率计达6.0%，为自2022年3月以来最快的一个月升幅。日本与欧洲的生产者价格数据也呈上升趋势，迫使政策制定者在稳定资产价格与维护长期政策可信度之间作出选择。

财政端同样恶化，因为借贷成本上升直接推高政府利息支出，同时经济放缓压抑税收，令大多数先进经济体几乎失去反周期操作空间。债券市场的「警戒者」已回归，尤其冲击日本与英国等较脆弱的G7主权债市场；而许多发展中经济体的财政与外汇储备缓冲也接近耗尽。结果是全球经济进入结构性再校准，市场必须面对更复杂的不确定性，直到政策灵活度重新恢复为止。

Policymakers’ capacity to respond to shocks is falling across the board. The article argues that for roughly three decades, major central banks and governments have often crossed the line from tolerating sell-offs to actively reversing them, even when market plumbing was intact and the real economy was sound, as in Q4 2018. That pattern strengthened investors’ belief in a “policy put,” making buy-the-dip a dominant strategy and helping global equities rebound quickly after the initial Iran-war shock.

But the current macro backdrop no longer supports such a safety net. Higher-for-longer inflation and interest rates, elevated debt, and structural changes in the world economy are tightening both monetary and fiscal constraints. Recent US data showed headline and core CPI above consensus, while the April producer price index rose at an annualized 6.0%, the fastest one-month increase since March 2022. Japan and Europe show similar upward pressure, forcing policymakers to choose between stabilizing assets and preserving long-term credibility.

Fiscal room has also largely disappeared in advanced economies because higher borrowing costs raise government interest bills while weaker growth hurts tax revenue. Bond vigilantes have returned, with the most vulnerable G7 sovereign debt markets—especially Japan and the UK—already feeling the strain. Many developing economies are also running down fiscal and reserve buffers, increasing risks of lower living standards, capital flight, and currency instability. The result is a bumpy structural recalibration in which markets must live with more uncertainty until policy flexibility improves again.