Pope Leo XIV’s sustained catechesis series on Vatican II documents and the September 2026 release of a major note reaffirming Nostra Aetate have reinforced trader consensus around the 91% “No” probability by signaling a clear priority on deeper implementation of the prior council rather than convening a new one. Ongoing Synod on Synodality work, with diocesan and continental stages planned through 2028 assemblies, further channels reform energy into existing structures without requiring an ecumenical council. Historical patterns show such gatherings are rare, publicly prepared well in advance, and absent from current Vatican calendars or consistory agendas. A late-year surprise announcement or papal pivot amid global church pressures remains a low-probability swing factor that could still test the market’s strong conviction.