What if an index-fund concentration unwind cascades through mega-cap stocks?
A passive-concentration unwind is mechanical: a vol spike forces risk-parity/vol-target deleveraging that sells highest-beta first, so Nasdaq and crypto (BTC, MSTR) lead the S&P lower as credit gaps wider. Rhymes with Feb 2018 Volmageddon and the March 2020 vol-target cascade. Forward angle: record index concentration in a handful of mega-caps means the reflexive feedback loop is more violent now than in 2018, with thinner single-name liquidity to absorb forced sales.
Every number ships with its receipt — the odds, the range, the precedents, and a public grade at Reality Check. The statistical machinery that produces it is proprietary.
The butterfly cascade
How this trigger trickles across markets, left → right — the root shock, its first‑order moves, then the ripple effects. Drag any node; tap a market for its real price history.
Resolution timeline — how this probability is moving
Our model's odds (electric blue) over time vs the market's (Polymarket, amber), from the past toward the 1–3 years horizon. Each dot is a real macro event that nudged the probability — green pushed it up, red pushed it down. Tap a dot for the source. Loading the probability audit trail…
What it would mean
If this plays out, it is a risk-off shock. A passive/index-fund concentration unwind cascades through mega-cap weights. The trigger decomposes into signed root‑shocks — Risk appetite ▼ · Volatility (VIX) ▲ — which propagate through our causal graph to the markets below.