The AI boom is being tested in two very different ways. China's AI shares have crashed. In the US, the strain is showing up in the debt of the most heavily borrowed builders, while the biggest spenders keep spending. This brief checks the numbers behind this week's headlines and sets out what to watch.
China's STAR50 AI and chip index in under four months, about $480bn erased
CoreWeave's five-year default insurance, against 63bp for US investment grade
Gartner's estimate of revenue AI data centres need by 2030, against at most $3.6tn they may earn
The STAR50 is down 40% and still trades near 100 times past earnings. Retail investors bore the losses.
Neocloud and Oracle debt is pricing real default risk. No neocloud has defaulted yet.
Amazon, Microsoft and Alphabet plan up to about $600bn of capex this year on growing cloud backlogs.
Reuters reports that China's AI rally ran higher than any in the West and has now unwound fast. AI stocks make up 42% of China's market value and 57% of turnover, Goldman Sachs estimates, so few small investors escaped.
Traders named no single trigger. They pointed to stretched prices, tax bills and the threat of US and other bans on Chinese equipment in data centres. Beijing's 9 October guidelines on high-tech growth told officials to avoid bubbles and herd-like investment. The securities regulator has announced no rescue.
Approximate falls from recent highs, to scale. Time windows differ, as labelled. Source: Reuters, 26 Oct 2026.
Even after the fall, the STAR50 trades at about 100 times trailing earnings (down from nearly 250), against about 30 for the Nasdaq 100.
Neoclouds rent out GPU capacity they bought with borrowed money. When rates rise, their sums get worse even if customers keep coming. That is why the stress shows first in their bonds and credit default swaps (CDS), the price of insuring their debt.
Five-year CDS spreads in basis points (100bp = 1% a year), to scale. 26 Oct unless noted.
Sources: S&P Global Market Intelligence via Benzinga (26 Oct); CNBC (Oracle, 19 Oct). Above 1,000bp is generally read as distress. Default odds implied by CDS depend on assumed recoveries, so treat them as rough.
Musk competes with neoclouds (SpaceX sells compute); Nvidia supplies and invests in them. Read both quotes with that in mind.
Gartner estimates data-centre owners need $8.5tn of cumulative revenue by 2030 to cover announced investment, financing costs and a 12% return on capital. It sees revenue attributable to AI data centres reaching no more than $3.6tn.
To scale. Gartner, 14 Oct 2026. These are model estimates, not results.
They measure different things, so they don't contradict each other. Always say which one you mean.
All AI infrastructure spending by AI providers in 2026, including neoclouds and labs (Gartner).
Hyperscaler capex expected in 2026, as cited by Neeraj Kaushal. Not all of it is AI.
Amazon, Microsoft and Alphabet combined in 2026, from company guidance (Reuters).
The veteran strategist told CNBC that air is coming out of the bubble without it bursting. His case: the bond market is rationing money to weak borrowers faster than rating agencies, so weak players fail or sell while stronger ones carry on.
Two dials out of 100. Conditions for a bubble are high; the triggers that usually pop one are not yet.
Conditions
Triggers
Rise from its December low, to scale (0–400bp). Red marks show the rises before the 2000 and 2006 busts.
air is coming out of the bubble without the bubble bursting
guppy-level death and consolidation
off the charts
a protracted investment bust
Past infrastructure manias destroyed capital but left assets that were used later. GPUs may be the exception.
of about £200m invested (roughly 40% of GDP) was lost to investors, Andrew Odlyzko estimates. The network was built and used.
of laid fibre was reported dark in 2001. Global Crossing went bankrupt with $12.4bn of debt. Much of the fibre was lit later.
is roughly how long a GPU stays competitive. Unlike fibre, stranded chips may age out before a second life. This is our inference.
Paul Krugman says it is. Columbia's Neeraj Kaushal points out that total US investment has barely moved, so AI may be reshuffling capital rather than starving the rest.
New York Fed, 14 Oct 2026. Bars start at zero, to scale.
Scale 0–25%. The NY Fed finds investment was reallocated rather than expanded: factories, other buildings and housing weakened as AI rose. Kaushal's column dates the later period from 2022; the NY Fed post uses 2023 to Q1 2026.
An FT editorial argues the bigger the boom grows, the fewer places there are to hide. Here is how the usual hedges look now.
| Hedge | Status | The catch |
|---|---|---|
| Credit default swaps | Costly | Insuring CoreWeave costs about 11.5% a year; protection on Amazon, Alphabet, Meta and Nvidia hit record prices too. |
| GPU rental futures | Not trading | CME and Silicon Data contracts were still under regulatory review on 26 Oct. They track chip scarcity, not share prices. |
| Treasuries | Mixed | They help in a slowdown, but not if the threat is a Fed hike. The 10-year yield is near 5%. |
| Gold | Volatile | Near $4,000 an ounce; it has swung hard this year. |
| Value stocks, Apple | Partial | Lighter on AI capex, but Apple sits in the same mega-cap indices. |
| Cash | Eroding | Inflation near 3.7% eats into real returns. |
Market levels are approximate quotes from 27 Oct and will have moved. Not investment advice.
Foreign investors have pulled money from India to chase AI and chip stocks in the US, Taiwan and Korea. When AI sold off, Indian IT briefly became the place to hide.
Index gains, 1–15 Oct, to scale. SBI Securities via Business Standard.
IT was the only large sector with foreign inflows (₹2,599 crore) while foreign investors sold ₹47,955 crore overall. Year-to-date foreign outflows reached a record ₹3.08 lakh crore by 12 Oct. The IT rally faded on 26 Oct.
Fed decision, 2pm ET (11:30pm IST); a hold is expected. Microsoft and Alphabet report after the close.
Amazon results, with heavy capex expected. US GDP and PCE inflation data.
US midterm elections, with data centres a local issue.
Anthropic shares reported to start trading on Nasdaq as ANT.
Fed meeting. Markets price roughly 73–80% odds of a hike, depending on the day.
The spenders are among the most cash-generative companies ever, and unlike in 2000, business saving has not collapsed. Cloud backlogs keep growing, and Anthropic's revenue rose roughly 14-fold in the first half. Gartner's ceiling is a model that bulls dispute. Even in the bear case, history says the infrastructure gets used and the losses fall on leveraged early financiers rather than the whole economy.
This brief starts from four pieces KK shared (Reuters, two Economic Times articles and an FT editorial) and checks their numbers against primary sources where possible. Figures are attributed and dated; estimates and forecasts are labelled.