Electrical steel topped an AI-capex relief bounce — Cleveland-Cliffs +6.5% on a Wells Fargo upgrade and a grid-steel expansion — as the power and optics rungs rebounded; SK hynix lagged, -4.5% in Monday's Seoul session.

Cleveland-Cliffs (CLF) led the compute basket on Friday, up 6.5% to $12.98, on the power-grid-and-generation chokepoint. Two catalysts stacked: Wells Fargo upgraded the stock to Overweight and lifted its target to $14 from $12, and the company detailed a $200m grain-oriented electrical-steel expansion at Butler Works backed by roughly $75m from a Department of Energy award. Grain-oriented electrical steel is the transformer-core material the datacenter power buildout runs through — the domestic-supply rung of the grid chokepoint — and it frames CLF as an AI-infrastructure name, not just a commodity steelmaker, ahead of Q3 results on Oct 19 (management has guided to about $575m in adjusted EBITDA, nearly double Q2's $286m).

The laggard was SK hynix (000660.KS), down 4.5% on the HBM-and-memory-bandwidth rung — but the timing needs a flag: Korean markets were shut Friday for Hangeul Day, so SK hynix's most recent completed session is Monday's Seoul close, where it fell to ₩1,605,000 as the KOSPI dropped 3.65% on heavy foreign selling. The move was macro and sentiment-driven — foreign outflows, Treasury yields, global-semis caution — not a memory-demand signal; HBM fundamentals remain tight. Among US names that actually traded Friday, the steepest decliner was Amkor (AMKR), −3.7% to $49.12 on the advanced-packaging-and-CoWoS rung, while Micron held nearly flat at $1,029 (−0.7%).

Friday was the relief bounce for the rungs Thursday had crushed. The power rung led it back: Talen Energy +5.4% to $378.57, Constellation +4.6% to $298.07, and Vistra +3.4% to $161.48. The optical-interconnect rung — Thursday's worst-hit — rebounded hard: Lumentum +5.2% to $1,103.36, Applied Optoelectronics +3.5% to $109.64, and Coherent +3.4% to $312.62. The capex layer firmed on the OpenAI-revenue reset: Amazon +3.3% to $262.43, Arista +2.7% to $216.74, Microsoft +2.4% to $535.07, and Quanta Services +3.0% to $705.94. Accelerators and leading-edge foundry lagged the rally, as they did all week: NVIDIA −0.5% to $229.28, Broadcom +0.4% to $361.54, and TSMC's ADR −1.0% to $453.31, with SoftBank +1.2% to $18.04 and CoreWeave +0.6% to $82.08 steadying after Thursday's drop.

The calendar lands on the rungs that moved. OCP Global Summit (San Jose, Oct 12–15) and SEMICON West (San Francisco, Oct 13–15) run back-to-back this week — the venues where interconnect, advanced-packaging, cooling and power-delivery roadmaps get set, the most likely next catalysts for the optics and power names. CLF's Q3 print lands Oct 19. Further out, Intel's 14A external-customer decision window opens at year-end, the domestic-foundry validation the leading-edge rung is still waiting on.