Refresh vs Sep 9 brief: Bloomberg/Yahoo cite late-Fri Nasdaq GIW pro forma SPCX weight ~1.28%→~2.82%; final weight later this month; Sep 21 effective still methodology-consistent; no IR results PDF yet; supersedes attributed JPM ~1.51%/$12.4B path.

SPCX Nasdaq-100 September 2026 rebalance refresh — GIW pro forma ~1.28%→~2.82% (post–Sep 11)

Generated by Grok Bot research on 2026-09-14. WebSearch + fetch ladder + one native-X attempt. Treat as raw material — review before promoting. Attach to existing pages only: spacex, spacex-lockup-calendar, spacex-ipo-index-inclusion-mechanic. Do not re-file Sep 9–10 unlock table (PR 144). Do not duplicate day-105 Sep 24 (~328.4M) calendar row. No buy/sell/size — Gage owns judgment. No encyclopedia.

Summary

Versus the Sep 9 vault brief (research-clip://spcx-n100-rebalance-sep-2026 / PR #210), the load-bearing change is not a new Nasdaq IR results release — that still appears unpublished as of 2026-09-14 — but a late-Friday Global Index Watch daily pro forma path reported by Bloomberg and fully retrieved via Yahoo Finance / Business Times / The Star syndications: SPCX NDX weight expected to rise to about 2.82% from roughly 1.28%, with the final weighting determined later this month. That path supersedes the prior attributed desk/JPM band of ~1.25%→~1.51% / ~$12.4B (secondary). Methodology still maps effective Mon Sep 21 open (first trading day after third Friday Sep 18) and announce Fri Sep 11 after close (sixth trading day prior); GIW circulation timing matches the announce window, but GIW pro forma is explicitly indicative / subject to change, and no primary dollar-flow figure is published — only qualitative “billions” of passive buying. Prior JPM $12.4B must stay attributed secondary and must not be recomputed against the new Δweight in this clip.

Findings

What changed vs the Sep 9 brief

Item	Sep 9 brief (PR #210)	This refresh (2026-09-14)
Weight path	Attributed secondary: desk/JPM Min Moon via Briefs ~1.25%→~1.51%	Bloomberg syndication citing Nasdaq GIW pro forma: ~1.28%→~2.82%
Dollar flow	Attributed secondary ~$12.4B (plus unreconciled ~$15.5B noise in HTX reprint)	No primary $ figure. Syndicated copy: “billions” of new buying only
Announce / effective	Methodology-mapped Fri Sep 11 AC / Mon Sep 21 BO — provisional (no IR release yet)	Same calendar mapping; GIW said circulated late Fri Sep 11; final weight later this month; IR September results release still not found
GIW / pro forma	Not yet observed	Cited by Bloomberg; raw GIW SPCX row not independently retrieved (login wall)

Sources for the new path: Yahoo Finance — Bloomberg syndication, 2026-09-12; Business Times reprint (dates GIW to Fri Sep 11); The Star Bloomberg reprint, 2026-09-14. Bloomberg.com URL exists but body was robot-blocked this pass: bloomberg.com article.

Calendar status — confirmed vs still provisional

Methodology primary (unchanged): Rebalance Effective = market open on the first trading day following the third Friday in September; Announcement = after close on the sixth trading day prior to that effective date; Reference Date = last trading day of August. Source: Nasdaq-100 Index Methodology (NDX PDF).
September 2026 mapping: Third Friday = 2026-09-18 → effective Mon 2026-09-21 open; six trading days prior → Fri 2026-09-11 after close. Still the correct rule mapping.
IR results release: Attempted canonical URL for September 2026 quarterly-changes returned Page Not Found (2026-09-14). Web search still surfaces only the June 2026 quarterly changes IR as the latest NDX quarterly results release. Treat Sep 11 announce as methodology/GIW-timing-consistent, not IR-confirmed.
Bloomberg language: “final weighting will be determined later this month” — so even the 2.82% / 1.28% pair remains pro forma, not the locked official post-announce weights.

GIW pro forma nature (primary channel constraints)

Nasdaq’s public Weighting tab documents that Daily Pro Forma is updated ~midnight ET weekdays, “as-is,” indicative of the projected basket for up to T+5 calendar days, and subject to change. Public page: indexes.nasdaq.com NDX Weighting (constituent/weight table login-gated this pass).
Licensed access how-to: GIW Website — Daily Pro Forma Guide (PDF). This bot did not retrieve the SPCX pro forma weight row from GIW itself — figures below are Bloomberg-reported GIW, not a direct GIW PDF/API pull.

Weight / flow — primary vs secondary grain

Primary-adjacent (Bloomberg → syndication, citing GIW): expected rise to about 2.82% from roughly 1.28%; final later this month; passive funds expected to buy billions; QQQ cited at ~$481B; ~$1.7T NDX-tracking AUM end-Q2 “according to Nasdaq” (as quoted in syndication — not re-fetched from a Nasdaq AUM primary this pass). Sources: Yahoo, Business Times, The Star.
Superseded secondary (keep attributed, do not promote as current base case): Sep 9-era Briefs / JPM Min Moon ~1.25%→~1.51% and ~$12.4B. Δweight under GIW pro forma (~+1.54 pp) is much larger than the JPM +0.26 pp path; do not multiply 1.54 pp × $1.7T here to invent a new flow — that would be desk math, not primary.
Mechanical why float can move weight (issuer methodology, not a SPCX float audit): Modified Market Cap = lesser of listed TSO or 3× free-float shares while float ≤ ~33⅓%; float updates only at quarterly reviews; Nasdaq does not anticipate future lockups until effective and documented. Sources: Methodology_NDX.pdf; 2026 NDX Changes FAQ.
Narrative driver in syndication (secondary color on lockups): July Fast Entry weight was float-constrained; subsequent lockup expirations expand free float → higher NDX weight; further unlocks may lift weight again. No share-count table re-filed here.

Vault attach context (refusals honored)

Attach only to existing spacex, spacex-lockup-calendar, spacex-ipo-index-inclusion-mechanic — this is the post-inclusion quarterly float-reweight demand pulse, not another Fast Entry event.
Do not re-file Sep 9–10 unlock eligibility table (PR 144 / vault calendar).
Do not duplicate day-105 Sep 24 (~328.4M) calendar row; if needed for supply overhang color against the Sep 21 demand window, point to vault spacex-lockup-calendar only.
No buy/sell/size recommendation.

Contradictions and open questions

GIW ~2.82% vs prior JPM ~1.51%: Large disagreement. Prefer GIW-cited pro forma as the newer Nasdaq-channel signal, but it is still indicative until final weights / IR results land. JPM path is historical secondary, not current base case.
Announce status ambiguous: Methodology + GIW timing point at Sep 11 AC, yet no Nasdaq IR September quarterly-changes release found on 2026-09-14, and Bloomberg says final weight later this month. Clarify whether Sep 11 was full results announce vs GIW-only circulation.
No primary dollar flow: “Billions” is not an operational size. Prior ~$12.4B was for a much smaller Δweight and must not be silently reused.
Raw GIW miss: SPCX pro forma weights not read from indexes.nasdaq.com without credentials.
Bloomberg.com body unread (robot challenge); syndication bodies used instead.
Native X miss: user-X search_news returned 403 monthly spend cap — no permalinks.
Open for Gage: wait for final Nasdaq weights / IR release before treating Δweight or any $ flow as operational fact; judgment on net demand vs later unlock supply remains Gage’s.

Provenance

Method: Grok Bot / WebSearch / fetch ladder (WebFetch → curl) / native X (one attempt) Generated: 2026-09-14 Prior brief: research-clip://spcx-n100-rebalance-sep-2026 (PR #210)

Web sources (actually retrieved this pass):

Misses / blocked:

Bloomberg.com original — robot challenge
Nasdaq IR September 2026 quarterly-changes page — 404 / not published as of 2026-09-14
GIW SPCX pro forma weight row — login-walled
Native X — 403 monthly spend cap

X sources:

none found — spend-cap 403 on 2026-09-14

Grokipedia:

not used