The source of Thursday's selloff hit compute hardest — SoftBank off 9.9% and the AI-optics complex down double digits, with Applied Optoelectronics the laggard at -13.6%; only cooling and power held.

The compute vertical was the epicenter of the session. The trigger hit this basket directly: a Financial Times report that OpenAI's annualized revenue was running near $50bn — below the roughly $70bn investors had assumed — repriced the entire AI-capex thesis the vertical maps. SoftBank (SFTBY), OpenAI's largest outside backer, took the most direct hit, down 9.9% to $17.83, and CoreWeave (CRWV), the neocloud rung whose demand is OpenAI-adjacent, fell 7.8% to $81.58. The only green of note was defensive and well off the accelerator: Ecolab (ECL) rose 1.3% to $281.69 on the datacenter water-and-cooling chokepoint, with GE Vernova (GEV) roughly flat (+0.2% to $999.35) as capital rotated toward the lowest-beta infrastructure rungs.

The laggard was Applied Optoelectronics (AAOI), down 13.6% to $105.90, at the front of an AI-optics selloff. AAOI sits on the optical-interconnect rung — the transceivers and fiber plumbing between accelerators — and that bottleneck trades as the highest-beta expression of the datacenter buildout. Coherent (COHR) −9.6% to $302.35 and Lumentum (LITE) −5.6% to $1,048.60 fell with it. No company-specific catalyst drove any of them; the move was the sector, and the interconnect names led the unwind precisely because they had led the thesis.

Memory gave back the prior session's record: Micron (MU) fell 4.8% to $1,035.84, after leading this basket up 4.1% to a record handle on HBM scarcity just a day earlier. The electricity chokepoint — the power rung the datacenter thesis leans on — sold too: Vistra (VST) −6.3% to $156.14, Talen Energy (TLN) −5.0% to $359.22, and Constellation Energy (CEG) −4.8% to $285.07, though GE Vernova held flat. Accelerators and leading-edge foundry came off with the chip gauge: Broadcom (AVGO) −4.3% to $360.14, NVIDIA (NVDA) −2.9% to $230.48, and TSMC's ADR (TSM) −3.0% to $457.99.

The near-term calendar lands squarely on the rungs that moved. OCP Global Summit (San Jose, Oct 12–15) and SEMICON West (San Francisco, Oct 13–15) back up against each other next week — the venues where interconnect, advanced-packaging and power-delivery roadmaps get set, and the most likely next catalyst for the optics and power names that just sold off. Further out, Intel's 14A external-customer decision window opens at year-end (estimated), the domestic-foundry validation signal the leading-edge rung is still waiting on.