Reason: ARM was the desk's biggest mover of the week: +36.31% over five sessions and +39.27% on the month, RSI now 71.1, part of Monday's broad chip rally the desk's own tape called a "CPU day." MRVL still owns the group's real structure — +249.64% on the year, +62.2% against its 200-day, still -20.91% below its high. PLTR added another 10.01% and remains the year's laggard at +5.06% (alpha -10.71). NVDA (+5.43%) and TSM (+6.91%) both extended quietly. AMZN (+1.35%) keeps the group's other negative one-year alpha (-2.83). 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 2026-09-18

• ARM +36.31% on the week, RSI up from 71.1 with 39.27% on the month and 58.2% against its 200-day — the tape now reads this name as intact but fully priced. Monday's session was documented by the desk's own brief as a broad chip and "agent-trade" rally (Intel, AMD and Arm all ran hard on that session, with Arm up over 17% on 3.2x normal volume) spilling out of buzz around a consumer AI-agent app; ARM's own news pull, refreshed September 22, returns only aggregator pages and names nothing company-specific.
• MRVL +13.58% week, +13.79% month, +62.2% against its 200-day, +249.64% on the year — no dated cause on file; its own pull (refreshed September 22) returns quote pages and points back to the August 31 earnings call as the last real event.
• PLTR +10.01% week; its news pull (refreshed September 19) resurfaces a recap of the already-known early-August earnings beat, nothing new dated to this week. Still the group's flattest year at +5.06%, alpha -10.71.
• NVDA (+5.43%) and TSM (+6.91%) both extended with no new dated cause; both pulls (refreshed September 22 and July 21 respectively) name nothing behind this week's moves.
• AMZN -4.88% on the month remains the one clear index laggard here at alpha -2.83; its pull (refreshed September 22) returns only a recap of the July earnings report.
• Roster unchanged since September 18: no entrants, no dropouts.

Sources

• Tape data (price, RSI, returns, one-year change and alpha, distance to the 200-day): pre-computed summaries as of the 2026-09-23 close — ai-infra (Schwab).
• Prior edition (format and roster only): 2026-09-18-ai-infra.
• Monday's chip/agent-trade session: 2026-09-21-market-brief.
• News checks: latest and .../MRVL/news/latest.json and .../NVDA/news/latest.json and .../AMZN/news/latest.json (all pulled 2026-09-22), .../PLTR/news/latest.json (pulled 2026-09-19), .../TSM/news/latest.json (pulled 2026-07-21, stale).