Will the ECB announce a 25 bps increase at the September 2026 meeting?

Logged 2 Sept 2026, 12:48 UTC · Brier 0.0036

• My knowledge ends well before September 2026, so I cannot independently verify the inflation path, OIS pricing, or ECB forward guidance; my estimate rests almost entirely on the outside view that well-telegraphed ECB decisions this close to the meeting are rarely surprises (the ECB in particular prizes predictability and 'effective communication' of its reaction function).
• The meaningful tail risk is concentrated in the final week: an inflation print surprise, energy/geopolitical shock, or a sudden shift in Governing Council signaling could produce a hold, a 50 bps move, or a pause — historically these tail events occur perhaps 3–8% of the time even when a move is near-fully priced a week out.
• The market price of 99.1% is above my 94% independent estimate; the divergence is plausibly explained by traders having real-time access to September 2026 OIS pricing, ECB speakers' pre-blackout commentary, and the August inflation print — information I structurally lack — so I treat the gap as a signal of my ignorance rather than clear market overconfidence, but I still shave a few points off 99% to account for genuinely unforecastable last-week shocks.

What would change it: A late-breaking inflation or energy shock in early September 2026 causing the ECB to hold or move by a different increment than 25 bps, announced in the September 9–10 statement.

-5.1 probability points from the market at generation · low confidence · Polymarket

Base rate: When a specific central bank rate move is fully priced by OIS/forward markets one week before a meeting, the move is delivered roughly 90–97% of the time, with misses coming from late data shocks or abrupt guidance shifts.

Chosen by hand.