Press note

Fed Decision Odds, Scored: Polymarket vs Kalshi at Every 2026 FOMC Meeting

87.5%Hike priced an hour before the decision

Both venues, 16 September 2026 17:00 UTC; the Fed raised 25 bp to 3.75–4.00% at 18:00 UTC. Multi-outcome Brier 0.029 Polymarket, 0.031 Kalshi, lower is better. The original 6 September study read the same Polymarket contract at 49.5%.

How Polymarket and Kalshi priced each 2026 FOMC decision, scored against the outcome. Both venues had the 16 September hike at 87.5% an hour out; the multi-outcome Brier was 0.029 on Polymarket and 0.031 on Kalshi. The FOMC raised the target range 25 basis points to 3.75–4.00% at 18:00 UTC on 16 September 2026. The two checkpoints below were locked by the forecast record before the announcement — 24 hours out and one hour out. The 14-day and 7-day checkpoints are absent because the record opened on 12 September. Both venues had the hike as the clear favourite at both checkpoints, and what was left over sat almost entirely on “hold” rather than on a cut. Polymarket scored a little better at both, 0.029 against Kalshi’s 0.037 a day out and 0.031 an hour out, but the two sums run over different contract sets, so the gap is narrow rather than decisive.

Observed 2026-09-15 to 2026-09-16, population: Polymarket and Kalshi September 2026 FOMC decision contracts.

Supporting figures

49.0% — Kalshi, 25 bp hike — 6 SepOriginal study, observed 2026-09-06 07:00 UTC. Hold 49.0%, cut 1.0%: last hourly candle close on KXFEDDECISION-26SEP.
3.5¢ — Largest daily gap, 30 days to 6 SepPolymarket minus Kalshi on the hike contract. The study's illustrative two-leg taker estimate at 50 cents was 2.75 cents; see the fees section for what that does and does not establish.
5,120 — Wallets on the three contracts, 7 days to 6 Sep13,659 fills, $5.90M notional; the round-the-clock cohort was 131 wallets making 19.8% of trades

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How to cite

Vultax Research, Fed Decision Odds, Scored: Polymarket vs Kalshi at Every 2026 FOMC Meeting, 2026-09-16, https://vultax.com/research/fed-september-decision-coin-flip-polymarket-kalshi

Published 2026-09-06, last revised 2026-09-16. Figures are the published study; live screens move. Plain-text version · Use our data