投资者因担心通膨高于目标及财政赤字难以控制，日益要求长天期政府债券提供更高的溢价。本周 30 年期美国公债殖利率升至 5.33%，创 2007 年以来新高；法国借贷成本触及 2008 年以来最高点，德国公债则交投于 2011 年水准。英国同等公债殖利率也正逼近 6%。

尽管债市尚未定价危机且短期债务相对平稳（如美国 2 年期殖利率过去一个月几乎未动，且 MSCI 世界股票指数接近新高），但 30 年期美国公债价格下跌正迫使资产配置者重新思考投资组合。随著长天期公债失去避险标签，对美国债务水准的疑虑也随之升温。

Yardeni Research 指出，市场越来越担忧超大规模企业借贷激增，并质疑若油价上涨，联准会是否能对通膨保持足够警觉。尽管殖利率上升反映后全球金融危机时代的结束，但若殖利率如 2023 年夏季般从 4% 飙升至 5%，未来或许会出现类似的买进机会，后续发展仍有待观察。

Investors are increasingly demanding a higher premium for long-dated government bonds due to concerns over above-target inflation and uncontrollable fiscal deficits. This week, the yield on 30-year US Treasuries rose to 5.33%, the highest since 2007. French borrowing costs reached their highest point since 2008, and German peers traded at 2011 levels. Equivalent UK gilt yields are approaching 6%.

Although the bond market is not yet pricing in a crisis and short-term debt remains relatively stable (e.g., the US two-year yield has barely moved in the past month, and the MSCI world equity index is near a record high), the tumble in 30-year US bond prices is forcing asset allocators to rethink portfolio mixes. As long-dated Treasuries lose their haven tag, doubts over US debt levels are rising.

Yardeni Research noted that the market is becoming more concerned about the surge in borrowing by hyperscalers and questioning whether the Federal Reserve will remain sufficiently vigilant on inflation if oil prices climb. While the increase in yields reinforces the passing of the post-global financial era, if yields surge from 4% to 5% as they did in the summer of 2023, there may be a similar buying opportunity ahead, and future developments remain crucial to watch.