Optical-interconnect name Credo led the AI-compute basket on analyst bullishness as the broader semi tape made records, while SK hynix fell in its own Seoul session on profit-taking.

The leader was Credo Technology (CRDO), up 6.3% to $182.28 on the optical-interconnect chokepoint — the active-electrical-cable and SerDes rung that moves data between accelerators as copper runs out of reach. The move was sentiment and analyst-driven rather than an earnings print: the Street stayed loudly bullish into a volatile name (beta ~3.25, consensus Moderate Buy with an average target near $263, well above Wednesday's close), on a tape where the Dow and S&P 500 set records and the Nasdaq Composite rose 1.05% to 26,702.86. Credo's relevance to the vertical is structural — its last quarter grew revenue ~115% year over year to $479 million on AI-cluster connectivity demand. The rest of the optical rung followed: Lumentum (LITE) +3.4% to $850.70, Coherent (COHR) +2.5% to $237.53, Arista (ANET) +1.7% and Marvell (MRVL) +1.8% to $244.76.

The laggard was SK hynix (000660.KS), down 5.5% to ₩1,223,000 in its most recent Seoul session, on the HBM-and-memory-bandwidth chokepoint — the tightest single strait in the AI stack. This was a home-market move on its own calendar, not the US tape: the stock gave back the prior session's gain on profit-taking off record highs ahead of its imminent Q3 report, where consensus looks for another record quarter on HBM4 volume. The US-listed memory rung did not follow — Micron (MU) rose 2.0% to $913.67 — underscoring that this was a Korea-session, flows-driven pullback rather than a demand signal turning.

The advanced-packaging rung, the back-end bottleneck that gates HBM stacking, was the day's real strength: BE Semiconductor (BESIY) +5.4% to $184.00 on hybrid bonding, Amkor (AMKR) +4.9% to $43.73 and Camtek (CAMT) +4.1% to $133.09. The power-and-grid rung — the datacenter's binding physical constraint — rallied hard with the nuclear complex: Constellation (CEG) +4.6% to $270.74, GE Vernova (GEV) +4.0% to $925.92 and Vistra (VST) +3.9% to $156.14, with cooling firm (Vertiv (VRT) +4.2% to $212.15). Lithography held up (ASML (ASML) +2.8% to $1,676.69) even as Lam Research (LRCX) slipped 1.0%; the accelerator anchors were mixed (NVDA +2.5% to $221.97, Broadcom (AVGO) +1.0%, TSMC's ADR (TSM) +1.6% to $431.89), CoreWeave (CRWV) −0.5%, and Merck KGaA's ADR (MKKGY) −2.6% was the soft spot in substrates.

The near calendar stays thin: the next dated milestone with structural weight is the year-end window for Intel's 14A external-customer decision, the domestic leading-edge validation the foundry rung awaits, opening December 31. Until then the memory signal controls the narrative — whether SK hynix's late-October print confirms the bandwidth chokepoint is tightening — while the power and advanced-packaging rungs, not raw chip demand, carry the session-to-session tape.