美国长期以来的债务警告过去常被视为「狼来了」，但如今飙升的国债正引发实质危机，并可能透过推高美债殖利率而直接冲击当前的人工智慧热潮。历史上的投机泡沫通常在借贷成本大幅攀升后破裂，而本次周期的债务过度积累主要集中在政府部门，公共债务的利息支出已在过去五年间倍增至GDP的3%以上，进一步推高了全球政府债券的殖利率。

目前衡量长期借款成本的重要指标是10年期美国国债殖利率，该数值若果断突破5%，很可能标志著低成本资金时代的终结并刺破AI泡沫。目前AI领域的年营收约为2000亿美元，远远落后于企业在资料中心与基础设施上超过1兆美元的资本支出；一旦债券殖利率突破5%，科技巨头将面临与政府争夺资金的排挤效应，使得发债与股权融资的难度大幅提高。

若10年期美债殖利率突破5%且维持在该水位，美国政府偿债成本将超过名义经济增长率，导致主权债务的可持续性严重恶化。尽管部分分析师将此比作1990年代的高利率与高成长环境，但如今美国公共债务已接近GDP的100%，庞大的利息负担将更迅速地排挤其他借款人，因此短期内最值得密切关注的正是殖利率突破5%的速度及其对AI繁荣的威胁。

Long-standing warnings about rising US debt were once dismissed like the boy who cried wolf, but runaway public borrowing is now triggering real market fallout that threatens to short-circuit the AI boom via rising bond yields. Historically, major bubbles burst when borrowing costs surged; however, this cycle's debt excesses are concentrated on government balance sheets, with US public debt interest payments doubling to over 3 percent of GDP and driving sovereign yields higher globally.

The critical benchmark to monitor is the 10-year US Treasury yield, which could burst the AI bubble if it decisively breaks above 5 percent. Estimated annual AI revenue sits around $200 billion compared to more than $1 trillion in capital spending on data centers and infrastructure; a Treasury yield exceeding 5 percent would force Big Tech to compete with government debt, crowding them out of financing channels and dampening stock market earnings yields.

Sustained 10-year yields above 5 percent would cause the borrowing rates paid by the US to surpass nominal economic growth, severely undermining debt sustainability. While some draw parallels to the high-yield, high-growth environment of the 1990s, the US debt-to-GDP ratio has since surged toward 100 percent, meaning heightened debt-servicing costs will squeeze other borrowers much sooner and hit the speculative AI market exceptionally hard.