The European Central Bank raises interest rates at its December 2026 meeting.

Question

Six frontier AI models put this at 70% by 12 Dec 2026. Full reasoning from every model.

WillHappen.ai · Accepted Answer

70% — the median of 6 frontier models, resolving by 2026-12-12.

Answer

Gemini (Google): 74% — The ECB must hike to anchor expectations after headline inflation rebounded to double its 2% target. Governing Council communication is pre-committed to acting if headline inflation persists above 3.5% through Q4. Central banks rarely back down within a one-month window once public signaling for a specific meeting rate rise is given. A severe plunge in November flash HICP or a banking panic before December 10 would be the only triggers to pause.

Answer

Claude (Anthropic): 28% — Hinges on whether October's inflation spike holds or looks transitory by the December 17-18 Governing Council meeting. ECB has held rates steady for most of 2025-2026, favoring a wait-and-see stance before reversing course. A single 4.0% inflation print after a long pause usually prompts verbal signaling before an actual hike, needing confirmation from November data. Central banks typically move gradually; a surprise December hike would require clear persistence in core inflation and hawkish consensus across the Council.

Answer

GPT (OpenAI): 63% — The call hinges on whether November inflation and wage data keep the ECB’s projected return to 2% implausible. The 4.0% October reading and explicit ECB signaling make a December move more likely than the usual late-cycle hike base rate. The Governing Council must agree on 10–11 December after receiving November HICP flash data and updated staff projections. A sharp November inflation fall or weak activity data would most likely turn a signaled hike into a hold.

Answer

Grok (xAI): 72% — Whether incoming data still justify the hike the Governing Council already flagged. Governing Council decides 10 Dec 2026; Oct HICP at 4 % already double the 2 % target. They publicly teed up a December move, so the default is a 25 bp hike unless data collapse. A sudden euro-area recession print or energy-price plunge before the meeting would most change the call.

Answer

DeepSeek (DeepSeek): 68% — It hinges on whether the December 2026 staff projections show inflation holding near 4% despite the growth drag. The Governing Council decides on 2026-12-10; Lagarde's October signal plus 4.0% HICP makes a hike the default unless projections break lower. Base rate: when the ECB explicitly flags a move a month out, it usually delivers — but 2022-23 hikes came with growth, and this cycle's downside risk is real. A November flash HICP print below 3.5% or a dovish Governing Council leak would flip me; absent that, a 25bp hike is the path of least resistance.

Answer

Qwen (Alibaba): 79% — ECB forward guidance with 4% inflation one month out makes a hike likely but not locked in. When the ECB signals a move one meeting ahead, follow-through historically exceeds 85%, but 'potential' is weaker language than a commitment. One month of data (November flash CPI, PMIs) could shift the calculus if inflation drops sharply or growth deteriorates materially. A financial-stability shock or sudden credit tightening would be the most plausible reason to delay; absent that, the 4% print alone sustains the case.

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