Full Signal · Oct 15, 2026 · 43m · 34m saved
With Kai Wu, Founder & CIO of Sparkline Capital
The Magnificent Seven now make up a third of the S&P 500. Kai Wu, founder and CIO of Sparkline Capital, told Phil Rosen, co-founder and CEO of Opening Bell Media, on the Full Signal podcast that the whole market is now riding on the AI trade.
Most investors who want AI exposure buy the chipmakers and hyperscalers doing the building. Kai reads the history of railroads, telecoms and electricity the other way: the builders rarely keep the gains, and the better bet is companies that put AI to work without paying for the buildout.
"The telecom index is down 90-plus percent and still hasn't recovered to its high-water mark twenty years later. The infrastructure builders, the guys who built out the fiber, ironically did not capture the gains." — Kai Wu
Kai studied historical capital cycles under Jeremy Grantham at GMO before founding Sparkline, which now runs two ETFs that buy companies cheaply relative to their intangible assets.
The full interview is covered here so you can skip it. 43 minutes of audio, 9 minutes of reading.
Here are the 10 calls that matter.
Key Takeaways
The AI trade is holding up the whole market while half of all stocks sit 20% or more below their summer highs
Nvidia and Micron explained about a third of last quarter's S&P earnings contribution
AI financing has moved past free cash flow into debt, banks and circular deals between suppliers and customers
Circular financing ties the AI complex together, so one stumble at OpenAI or CoreWeave could spread
Frontier AI labs have weak moats, trailing one another by three to six months with low switching costs
Chips remain a boom-bust business, and Kai doubts the claim that this cycle is structural
Infrastructure builders did not capture the internet's gains; Netflix and Google did
Early adopters with intangible moats are Kai's preferred AI bet, at prices close to the laggards'
1. A Market Held Up by AI
Kai describes a stock market split in two. AI infrastructure winners prop up the index, while more than half of all stocks have dropped 20% or more from their summer highs. Many former software darlings are down 50% to 80% on fears they have no moat.
Kai Wu says a handful of AI names now carry both the index and its earnings
"The magnificent seven stocks are now 33% of the S&P, combined with this selloff in the perceived losers of AI." — Kai Wu
The concentration shows up in profits as well as prices. A few chip and cloud names account for a large share of the S&P's earnings growth.
"Nvidia and Micron explained about one-third of the earnings contribution from last quarter, followed by the Broadcoms and the hyperscalers." — Kai Wu
Phil raised the statistic that the share of stocks beating the index is near its 1990 lows. Kai read it less as a late-cycle warning than as a mechanical result of that concentration, plus a trillion-dollar capex buildout lifting a narrow set of AI-adjacent companies.
