The U.S. Consumer Price Index for September 2026 rises month-over-month when released on October 13, 2026.

Question

Six frontier AI models put this at 77% by 24 Oct 2026. Full reasoning from every model.

WillHappen.ai · Accepted Answer

77% — the median of 6 frontier models, resolving by 2026-10-24.

Answer

Gemini (Google): 82% — Persistent shelter costs and sticky core services make month-over-month headline CPI prints positive over 80% of the time historically. BLS seasonally adjusted monthly headline CPI has increased in roughly 82% of all months over the last two decades. A negative print requires severe energy price deflation to overpower steady baseline inflation in services and housing. A sharp sudden crash in late-September crude oil prices would be the primary catalyst pushing the monthly print to zero or below.

Answer

Claude (Anthropic): 93% — Monthly CPI almost always rises MoM absent deflationary shocks; this is a base-rate call. Historically MoM CPI is positive in roughly 90-95% of months outside recessions or oil price collapses. No current signals point to a deflationary September 2026 given tariff-related and sticky services inflation pressures in 2025-2026. Main risk to 'no' would be a sharp energy price drop or major data revision, which is uncommon but not impossible.

Answer

GPT (OpenAI): 71% — The outcome chiefly depends on whether core services and housing inflation offset any September energy-price drop. BLS needs only publish its scheduled September CPI release on October 13; no policy or legislative action is required. Since 2010, headline CPI has increased in roughly three quarters of months, making a positive print the normal outcome. A sharp September gasoline decline or broad goods-price deflation would most materially lower the odds.

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Grok (xAI): 82% — September CPI MoM is positive unless energy/food collapse in the remaining week. BLS prints SA MoM on Oct 13 using data through Sep 30; only the last 6 days of September remain unobserved. Historically ~80-85% of months show positive SA CPI MoM outside deep recessions or oil crashes; August already +0.2%. A late-month gasoline plunge or shelter miss would flip it; neither is priced in current futures or rents.

Answer

DeepSeek (DeepSeek): 72% — Monthly CPI prints are positive far more often than not; the question is whether September's energy and shelter components break that pattern. BLS has reported positive month-over-month headline CPI in roughly 7 of every 10 months since 2010, so the base rate sits near 70% before any current-conditions… September typically brings modest seasonal softness in energy and used vehicles, but shelter and services inflation have been sticky enough in 2026 to keep headline… The single development that would most change this is a sharp September crude oil price drop or an unusually large seasonal decline in gasoline, which could pull the…

Answer

Qwen (Alibaba): 68% — CPI MoM is positive ~70% of months historically; tariff pass-through and shelter stickiness keep the base rate elevated. Since 2020, CPI MoM has been positive in roughly 75% of readings; the 0.2% August print confirms ongoing upward drift. Tariff effects from 2025 are still feeding through to goods prices, and shelter OER lags keep services inflation positive. A negative print would require a sharp energy drop (oil below ~$60) or a deflationary goods shock, neither of which is priced in.

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