The extreme rarity of magnitude 10.0 earthquakes drives the 98.6% market-implied probability against occurrence before 2027. No such event has been recorded in modern seismology; the largest measured was 9.5 during the 1960 Valdivia quake, limited by the physical constraints of fault rupture area and slip on subduction zones per USGS and peer-reviewed moment-magnitude scaling. Great earthquakes (8.0+) occur roughly once every 5–10 years globally, making a 10.0 threshold in the remaining months statistically remote even under peak tectonic stress. Any shift would require an unprecedented rupture exceeding historical maxima, which monitoring networks like the USGS Global Seismographic Network would detect immediately if conditions aligned.