FormFactor led the back-end test rung on an Nvidia probe-card win as money rotated out of the data-center power names.

FormFactor (FORM) led the vertical, up 9.6% to $149.31, on the back-end test-and-probe-card rung. Deutsche Bank initiated the stock at Buy with a $200 target, and FORM was confirmed as a second qualified probe-card supplier for Nvidia GPUs built at TSMC. Probe cards are the contact interface that screens every AI accelerator at wafer test — a low-profile but genuine chokepoint, since a second-source qualification at the dominant GPU customer entrenches FORM on the packaging-and-test rung the whole compute buildout depends on. It extended a strong run that has carried the stock toward its 52-week high.

The laggard was Constellation Energy (CEG), down 4.0% to $254.02 — notable because it fell on the same day Constellation and Amazon were reported to have signed a 20-year power deal supporting a Maryland nuclear plant. The decline was valuation-driven; CEG trades at a rich multiple, and the whole power-for-data-centers rung de-rated with it. The signal is a rotation out of the energy layer, not a crack in compute demand.

That rotation defined the tape. The power, cooling and thermal names were broadly red: Vistra −1.8% to $138.35, Vertiv −2.8% to $241.31, and GE Vernova −1.2% to $950.49 alongside CEG. Advanced-packaging/OSAT softened too, with Amkor −3.3% to $52.38 and SoftBank's ADR −2.2% to $65.75. The bid instead went to memory and manufacturing capacity: SK Hynix rose 3.2% in Seoul on the HBM rung, Intel added 3.7% to $120.23, Lam Research +1.4% to $328.51, Camtek +1.6% to $155.25 (cooling from the prior session's 7.2% jump), Credo +1.3% to $194.79, and Modine +1.9% to $187.20 on liquid cooling. The neocloud rung held, CoreWeave +1.4% to $87.12. The through-line: on a quarter-end session where the Nasdaq rose 0.2%, conviction sat in test, equipment and memory — the true bottleneck — rather than the electrons.

The catalysts ahead are consolidation- and conference-driven. Ecolab's roughly $4.75 billion CoolIT acquisition is expected to close this quarter, tightening the liquid-cooling rung. OCP Global Summit (Oct 12–15, San Jose) and SEMICON West (Oct 13–15, San Francisco) are the next hardware and equipment showcases — the latter the venue where FormFactor is co-hosting its CEO Investor Summit and where advanced-packaging and cooling roadmaps get set. The OpenAI Q4 IPO window remains the private-compute wildcard, and Intel's 14A external-customer decision window opens at year-end, the domestic-foundry validation signal the whole vertical is watching.