安联投资团队以「牛顿摆」为比喻，指出美国企业信用市场的风险并未消失，只是在投资级债券、高收益债券与私募信贷之间不断转移。表面上利差收窄、市场平静，但每个环节的定价都因不同机制而与基本面脱钩：投资级债靠「对殖利率不敏感」的需求压缩利差，高收益债靠最弱借款人外移改善组成结构，私募信贷则靠净资产估值平滑掩盖坏帐压力。

投资级债券方面，美国投资级利差约75个基点，比伊朗战争前还窄，但利息覆盖率和净杠杆率均已走弱。最大隐患在BBB级底部：一旦遭降级为「堕落天使」，指数型投资人被迫抛售至流动性更差的高收益市场，造成远超信用品质变化的利差波动。净升级率已连续约三年为负，目前极窄的利差几乎没有缓冲空间。高收益债方面，BB级占比逾五成、CCC级降至二十年低点，加上平均存续期仅三年，看似防御性较强，但这主要是因为最弱的借款人已转向杠杆贷款和私募信贷。

在私募信贷中，因采用评估定价而非市场定价，净资产值表面平稳，实际上借款人杠杆高达五至七倍、利息覆盖率仅一至二倍。实物支付利息（PIK）比例已从2023年初的4.3%翻倍至8.9%，贷方接管规模在2025至2026年达394亿美元，约为此前三年总和的三倍。安联警告，一旦市场承压，风险可能回流至公开高收益债市场——因为私募信贷和高收益超配部位难以迅速退出，投资人往往优先抛售流动性最高的公开高收益债，使其成为私募信贷的「非自愿避震器」。

Allianz's investment team uses the metaphor of a Newton's Cradle to argue that US corporate credit risk has not been eliminated but merely relocated across investment-grade (IG) bonds, high-yield (HY) bonds, and private credit. Each segment masks deteriorating fundamentals through a distinct mechanism: IG spreads are compressed by yield-hungry, price-insensitive demand; HY's index composition looks cleaner because the weakest borrowers have migrated out; and private credit smooths its NAV through appraisal-based valuations rather than market pricing.

In IG, spreads sit at roughly 75 basis points despite softening interest coverage and rising net leverage, leaving almost no cushion against fallen-angel downgrades that could erode up to one-third of current spread under stress. HY appears defensively positioned with BB-rated names exceeding 50 percent of the index and CCC at a 20-year low, but this strength is largely a composition effect from the exit of the weakest credits. Meanwhile, in private credit, structurally weaker borrowers carry leverage of five to seven times, payment-in-kind interest has nearly doubled to 8.9 percent of income, and lender takeovers have surged to $39.4 billion across 2025–26.

Allianz warns that under market stress, the risks exported from public HY could boomerang back. Because crowded private-credit and HY-overweight positions cannot be unwound quickly, investors seeking to de-risk will sell the most liquid public HY first, driving spreads wider than the improved credit composition would justify. In effect, public high-yield bonds risk becoming the involuntary shock absorber for private credit—absorbing liquidity-driven selling pressure rather than reflecting their own fundamentals, making the entire credit chain more fragile than surface-level metrics suggest. (Key numbers: 2023, 4.3, 8.9, 2025)