Question: SpaceX net-flow model — forced passive index demand vs staggered lockup supply (parametric) Verdict: early-index-inclusion-bid-~4-to-30B-tiny-vs-lockup-supply-~150-to-350B; net-flips-from-bid-to-overhang-at-the-Q2-earnings-release-~aug-sep; passive-bid-is-an-order-of-magnitude-too-small-to-absorb-the-lockup; quantifies-and-dates-the-economist-near-term-bid-medium-term-capital-diet

What we're asking

The lane's central tension, quantified and dated: on each scheduled event, is the forced passive index DEMAND bigger or smaller than the insider SUPPLY (IPO float + staggered lockup releases)? Where demand > supply → net bid; where supply > demand → net overhang. This converts "near-term bid vs medium-term capital diet" (Economist) into a dated net-flow curve and a falsifiable prediction.

Status: parametric. The S-1/A offering is still blank, so raise/float/price are press numbers. The model is a function of (raise R, valuation V, insider- sell fraction s); rerun when the deal prices. It is order-of-magnitude — the value is the sign and the ~10× asymmetry, not precision. Arithmetic done in code (reproduced below), not prose.

Assumptions (base case, all overridable)

Re-weight demand: as lockup releases expand the float, free-float index weights rise → trackers must buy more (S&P/Russell linear in float; NDX 3× cap not binding below ~33% float). Supply = released value × s.

What we found

1. Early index-inclusion demand is tiny, and arrives with supply locked

Mechanical early demand (Russell+NDX) ≈ $4B, with lockup intact (supply ≈ 0). So June–July is a modest net bid — but trivial next to the $75B IPO float and the stock's own daily volume. Sensitivity to raise size: $40B→$2.1B, $75B→$4.0B, $120B→$6.4B early demand.

2. The lockup window flips hard negative — supply dwarfs the re-weight bid

Net-flow curve, base case (s=30%, S&P not yet in by the lockup window):

Even if S&P 500 were already in (adds re-weight demand), every tranche stays net negative (Q2 −$26B, Q3 −$37B). Cumulative net through the Q3 release:

3. The model (reproducible)

V, R = 1.75e12, 75e9; float0 = R/V
IDX = {"Russell1000(T+5)":(1.5e12,0.0010), "NDX(T+15)":(0.5e12,0.0050), "S&P500(cond)":(6.0e12,0.0010)}
POOL, s = 0.45, 0.30
LADDER = [("+7% T+70",.07),("+7% T+90",.07),("Q2 +20%",.20),("+10% trigger",.10),
          ("+7%x3",.21),("Q3 +28%",.28),("180d rem",1-(.07+.07+.20+.10+.21+.28))]
w = lambda w0,fl: w0*(fl/float0)            # free-float linear (NDX cap non-binding <33%)
fl=float0; cum=0
for name,frac in LADDER:
    cum+=frac; nf=float0+POOL*cum
    dem=sum(a*(w(w0,nf)-w(w0,fl)) for a,w0 in [IDX["Russell1000(T+5)"],IDX["NDX(T+15)"]])
    sup=frac*POOL*V*s; print(name, round((dem-sup)/1e9,1)); fl=nf

Verdict + reasoning

The forced passive bid ($4–30B across the index legs) is an order of magnitude too small to absorb the staggered lockup supply ($150–350B of eligible-to-sell through Q3 at s=15–50%). The net flow flips from a modest bid to a large overhang at the Q2-2026 earnings release (~Aug/Sep). This is the dated, falsifiable form of the Economist/Haghani "near-term bid, medium-term capital diet."

Maps onto the lane hypotheses with a timeline:

• June–July (T+5/T+15): modest net confirms-passive-flow-bid, but small — watch for abnormal volume near the dated inclusions; don't expect much.
• Aug–Oct (lockup ladder): large net confirms-lockup-overhang / confirms-liquidity-drain — the supply overhang is the dominant force, and it is dated (Q2 then Q3 earnings releases are the step-ups).
• The book-build/funding-pocket drain (moomoo) is a separate, even earlier channel (T-7→T-1) not in this model — additive to the bear case if it fires.

Load-bearing caveats (why this is a risk-gauge, not a price target):

1. Insiders don't have to sell. s is the swing variable; Musk's ~half is locked 366d with no early release, capping worst-case supply. But the ~10× asymmetry means even s=15% overwhelms the bid.
2. Supply is eligible-to-sell, not actual — but the asymmetry is the point.
3. Reflexive ceiling: the +10% tranche releases only if the stock runs ≥30% above IPO — so strength mechanically brings supply, a self-limiting cap.
4. Wide error bars on AUM and the pool fraction; price held flat (a falling price shrinks $ supply but also $ demand). Rerun when the deal prices and lockup share counts are fixed.

Follow-through

• Lane T+30/lockup gate now carries a quantified expectation (net overhang from the Q2 release); passive-flow-bid and lockup-overhang hypotheses updated with the model's magnitudes. Desk-Pass Log appended.
• Rerun trigger: when the S-1/A offering blanks fill (priced deal) — recompute float, weights, and the lockup share counts.