The US stock AI rally is not over, but where is the money coming from to push the index higher, and how much fuel is left? Subtle changes are now emerging.

From March 30 to May 8, the S&P 500 rose approximately 16.6% over 28 trading days. But when breaking down the structure of this rally, the pattern is completely different.
According to data from Nomura’s Vol team, citing TECHi, 10 stocks contributed 69% of the gains, while the remaining 490 component stocks contributed only 31%.
These 10 are: $NVDA $GOOG $MSFT $AMZN $AAPL $AVGO $AMD $INTC $MU $SNDK
, including 7 AI chips/semiconductors and 3 mega-scale cloud providers.
Almost the entire AI infrastructure supply chain is covered.
Goldman Sachs US equity strategy chief Ben Snider directly pointed out: the current market breadth has shrunk to one of the narrowest levels since the internet bubble era.
Meanwhile, behind the seemingly enthusiastic surface, abnormal signals have already appeared. The index hits new highs, but the VIX (17.19), SKEW (138.21), and VVIX (96.78) indicators are all rising simultaneously. Institutions are not lowering hedges in the face of new highs.
Nomura describes this combination as an abnormal situation of “spot prices rising while volatility also rises.”
More critically, the funding environment: Nomura believes that the three main forces pushing up AI stocks in recent weeks—short covering, CTA long positions, and vol-control leverage—are now approaching their limits.
The phase driven by “shorts being squeezed” is nearing its end.
So who will take the next step?
Nomura’s answer is to watch Korea.
On the day the research report was released, the KOSPI surged 4.32% in a single day to 7,822.24 points, triggering buy-side flow during the session. SK Hynix soared nearly 12%, with its market cap surpassing Eli Lilly for the first time, ranking 14th globally.
Retail investors fell into “Hynix FOMO,” and overseas funds increased their chip stock holdings through DRAM ETFs.
The momentum behind US stock AI trading is shifting from “shorts being squeezed” to “retail FOMO,” with the narrative moving from the Nasdaq to the KOSPI.