Indexes
The companies building AI, measured together: how they are doing, how much of the market they are, and how much the market pays for their profits.
US AI 100
3,246.35
+0.10%Close Oct 1, 2026
How are the companies building AI doing, together, weighted by size?
AI share of US market cap
41.9%
−0.01%Close Oct 1, 2026
How concentrated is the market in AI companies?
AI valuation premium
1.38×
−0.01%Close Oct 1, 2026
How much extra am I paying for AI? A widening premium needs stronger growth or more durable profits to justify it.
AI P/E ratio
33.9×
+0.10%Close Oct 1, 2026
How much actual profit am I buying? Compare semiconductors, software and hardware separately.
US AI 100
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Values before Oct 2, 2026 are back-tested: the editors' list of that day, run backwards. Company filings and exchange prices; calculations by The Inference.