Earthquake magnitude scales directly with fault rupture length and area, and no known tectonic feature on Earth approaches the roughly 10,000-kilometer scale needed for a 10.0 event. USGS analyses confirm the physical upper bound lies near 9.5–9.7 along the longest subduction zones, matching the 1960 Valdivia, Chile quake—the largest instrumentally recorded. With fewer than 18 months until 2027 and no new seismic data, modeling updates, or tectonic observations suggesting larger ruptures, trader consensus correctly prices the outcome as effectively impossible under current geophysical constraints. Only an unforeseen discovery of a previously unknown planet-spanning fault could alter this assessment.