What if a 30-year Treasury auction draws a record tail?
A record auction tail is a pure term-premium / real-rate shock: 30y yields gap higher, and long-duration tech (Nasdaq, high-multiple semis like Arm) de-rates hardest as the discount rate rises. Rhymes with the autumn-2023 supply-driven selloff that pushed 10y to ~5% and crushed duration. The mechanism is dealer balance-sheet indigestion; the forward angle is that QT-shrunken dealer capacity makes tails fatter than the 2010s — buy-the-dip in duration only once a concession is built.
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 0–6 months 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 30-year Treasury auction draws record tail and lowest bid-to-cover, spiking long-end yields. The trigger decomposes into signed root‑shocks — Credit spreads ▲ · Real yields ▲ — which propagate through our causal graph to the markets below.