The artificial intelligence bottleneck is the most important theme in the stock market, right now.

That's the view of J.P. Morgan analysts, who said their bullish outlook on equities hinged on the AI momentum narrative.

The bottleneck theme includes just a handful of companies with "the scale, expertise, and access to supply the critical components that keep the AI economy running," they added.

Supply constraints are most acute in high-bandwidth memory chips, dominated by SK Hynix, Micron, and Samsung; photonics by Broadcom and Coherent; and cooling management, where they cited Vertiv and Modine. They also mentioned energy generation and grid infrastructure.

"These companies are not just suppliers, they are critical to the next phase of AI growth, with market power and technical barriers that are not easily overcome."

All of those stocks have enjoyed stellar gains so far this year--Micron and SK Hynix are up more than 200%, Samsung has jumped 190% and thermal technology company Modine has climbed more than 100%. Data-center equipment maker Vertiv and optical networking company Coherent have almost doubled, while semiconductor giant Broadcom is up around 30% in 2026.

But the cohort could be in for even more gains if the supply shortages persist.

"Investors are shifting focus from capex spenders to firms that control these bottlenecks," the analysts added. "In this cycle, the real winners will be those who own the bottleneck, as relentless demand turns scarcity into outsized returns."