The AI-power trade cracked — SMR developers and enrichers were dumped as investors demanded proof of delivery, while the profitable utilities held up.

The "leader" tells the story by how little it moved: Japan Steel Works (JPSWY), the reactor-pressure-vessel forging supplier at the construction chokepoint, was the vertical's top mark at just +0.9% to $26.50. Nothing else in the basket was meaningfully green. This was a sector-wide de-rating, not a rotation within it — the whole complex that had traded as a levered call on datacenter power demand got sold as the AI trade cooled.

The laggard was NANO Nuclear Energy (NNE), down 9.3% to $16.20, at the front of a broad developer rout: Oklo (OKLO) −8.7% to $41.70 and NuScale (SMR) −8.6% to $7.64 fell with it. The driver was explicit — investors rotating out of Wall Street's most expensive AI-linked trades and shifting from enthusiasm about future power demand to scrutiny of whether advanced-reactor companies can actually hit their timelines. Oklo has now shed roughly 28% in a month; NuScale sits far off its highs. Enthusiasm is being repriced into execution risk.

The fuel-and-enrichment layer went with the developers: X-Energy (XE) −8.2% to $13.83, Uranium Energy (UEC) −7.7% to $9.33, Denison (DNN) −7.8%, and merchant-power name Talen (TLN) −8.0% to $368.29. But the split that defines the sector held: the cash-flowing utilities took far less damage — Constellation (CEG) −2.5% to $251.77 and Vistra (VST) −4.8% to $152.56 — because their earnings are real today, not a 2030s option. When the trade de-risks, the market keeps paying for delivered megawatts and dumps the promise of future ones.

The next reads are dated and dense. GE Vernova reports July 22, NextEra July 29, Constellation July 30 and Cameco July 31 (with Westinghouse-equity color); Talen, BWXT and Centrus follow in early August, then Oklo on August 10, NuScale August 12 and X-Energy on the 13th — the developer prints where the timeline-versus-cash-burn question this selloff was pricing gets its first hard test. Watch the DOE reactor-pilot criticality milestones and the NRC's Xe-100 construction-permit review (18-month mark December 16) as the execution proof points the tape is now demanding.