Geophysical constraints on fault rupture length and slip make a magnitude 10.0 earthquake physically impossible on Earth, anchoring the 98.8% market-implied probability for "No." The largest instrumentally recorded event reached 9.5 in Chile in 1960, with USGS catalogs confirming no 9.0+ events in recent years and typical global maxima near 8. No subduction zone or fault system provides the ~1,000+ km rupture dimensions required for 10.0, per established scaling relationships. With only months remaining until the December 2026 resolution and continuous USGS monitoring showing baseline seismic activity, trader consensus reflects this evidence. Only an unprecedented revision to magnitude estimation methods or an undetected deep event could theoretically alter the outcome, though both remain outside observed geophysical limits.