What if a large nonbank mortgage servicer fails under margin calls?
A nonbank servicer failing on margin calls against servicing advances disrupts MBS cashflows and spikes mortgage-basis/agency-MBS spreads as advance funding dries up. Rhymes with the spring-2020 servicer-advance scare (Ginnie Mae forbearance) that briefly threatened names like Mr. Cooper before liquidity facilities calmed it. Skeptic's note: this is a plumbing/advance-funding shock, not a credit-loss shock — the cleaner trade is the MBS basis and mortgage REITs, not broad HY.
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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 6–18 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 large nonbank mortgage servicer fails under margin calls on servicing advances, disrupting payments to MBS holders and homeowners alike. The trigger decomposes into signed root‑shocks — Credit spreads ▲ · Financial conditions ▲ · Risk appetite ▼ — which propagate through our causal graph to the markets below.