What if Apple blocks all cross-app ad tracking on the iPhone?
Killing all cross-app identifiers vaporizes mobile ad-targeting — a direct revenue hit to Meta/Snap/adtech, hence the deeper risk-off and VIX bid. The exact analogue is Apple's 2021 ATT rollout, which erased an estimated $10bn from Meta's 2022 revenue and halved Snap's stock in a day. Forward angle: this time first-party data and on-device AI modeling are more mature, so walled-garden incumbents (Meta, Amazon) relatively gain share as open-web adtech bears the loss.
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. New iOS privacy default blocks all cross-app identifiers, vaporizing mobile ad-targeting and adtech valuations. The trigger decomposes into signed root‑shocks — Risk appetite ▼ — which propagate through our causal graph to the markets below.