Reason: PLTR led the basket this week (+6.22%) and is still its weakest name over twelve months — +0.38% on the year with alpha -14.64, the only name here that has not kept pace with the index. MRVL stays the structural leader: +229.04% on the year, +54.2% against its 200-day, still -25.96% below its high — a deep pullback inside an intact trend, not a breakdown. ARM did the most on the month (+10.54%) and carries the widest unrecovered drawdown (-39.12%). NVDA and TSM marked time. AMZN was the only red name on the week (-1.2%) and keeps the group's only other negative one-year alpha (-5.29). Roster unchanged.

Price/RSI Table

Status reads the 200-day trend first and RSI second; Action is a trend-hold lens — an extended name is never an entry, and a name below its 200-day with a negative year is not a dip.

What Changed Since 2026-09-11

• PLTR had the best week and has the flattest year: +6.22% since September 11, +0.38% over twelve months, alpha -14.64. Short-window strength has not become long-horizon leadership. Its news file was last pulled August 8 — news not pulled for this week's move.
• MRVL +3.45% on the week, +229.04% on the year, +54.2% against its 200-day and -25.96% off its high. A September 17 portal summary on its pull credits AI-infrastructure demand and an expanded manufacturing partnership; no filing on file carries either, so the cause stays unconfirmed.
• ARM +4.09% on the week and +10.54% on the month, +33% against its 200-day, yet still -39.12% below its high — the largest gap to old highs in the group.
• NVDA (+1.82%) and TSM (+0.33%) marked time, both in uptrend at +12% and +14.6% against their 200-days with one-year alpha of +11.1 and +46.79.
• AMZN is the only decliner: -1.2% on the week, -4.56% on the month, +9.72% on the year at alpha -5.29 — the clearest index laggard here.
• Roster unchanged since September 11: no entrants, no dropouts. TSM's last completed pull is July 21 and PLTR's August 8, so neither week's move has news behind it; NVDA, ARM, MRVL and AMZN pulls completed September 17-18 and return quote and overview pages with nothing dated behind the moves. Nothing for these names sits in the desk's event record this week.

Sources

• Tape data (price, RSI, returns, one-year change and alpha, distance to the 200-day): pre-computed summaries as of the 2026-09-18 close — ai-infra (Schwab).
• Prior edition (format and roster only): 2026-09-11-ai-infra.
• News checks: latest (pulled 2026-09-18), .../NVDA/news/latest.json, .../ARM/news/latest.json, .../AMZN/news/latest.json (all pulled 2026-09-17), .../PLTR/news/latest.json (2026-08-08), .../TSM/news/latest.json (2026-07-21).