September CPI ladder resolves: Kalshi 0.6% threshold settles NO as BLS prints 0.59%

The September Consumer Price Index ladder on Kalshi resolved on Wednesday the way the bracket math said it should, and the margin is the whole story. BLS reported a 0.59% seasonally adjusted monthly rise for September, which put the headline between two settled thresholds: the 0.5% contract paid out YES while the 0.6% contract settled NO. Traders who held the boundary got the sliver right, because 0.59% clears 0.5% and stops short of 0.6%.

The resolution closes a five contract ladder that had been live since mid September. On the day the desk first priced the print, the 0.5% contract carried an implied probability of 58.5%, the 0.6% threshold priced near 14%, and the 0.7% threshold near 0.5%. The settled outcomes line up with those pre-release prices: the 0.5% contract resolved YES at a final last price near 0.68, the 0.6% contract resolved NO, and the 0.7% contract resolved NO. A market can be wrong about a point estimate and still bracket the outturn correctly, and that is what happened here.

Related reading: September CPI market: Kalshi 0.5% contract settles YES, October Fed hike odds jump to 36.5%.

The year over year leg resolved the same way. The 3.6% annual threshold settled YES after BLS put the twelve month rate at 3.74%, up from the 3.4% August reading this desk tracked in the run up to the release. The index itself, seasonally adjusted, came in at 336.940 for September against 324.800 a year earlier, a 3.74% annual gain that the CPI YoY contract captured cleanly.

What matters for the event market is what the print did to the October Federal Reserve pricing. Kalshi's KXFED-26OCT ladder, which settles after the October 28 FOMC decision, currently prices about a 23.5% chance that the upper bound of the federal funds rate ends above 4.00%, with the 4.25% threshold bid at essentially zero. That is a materially different reading from the 36.5% October hike probability the desk quoted from Polymarket's hold contract before the data settled, a divergence worth flagging for anyone who treats the two venues as interchangeable.

For the broader framework, see our Fed policy coverage.

Related reading: CPI Market Prices a 58.5% Chance of a 0.5% Rise.

The divergence is a reminder that identifier screens differ. Polymarket's October contract asks directly whether the Fed holds in October, and its market cleared near a 62.5% hold probability on the day of the print. Kalshi's ladder expresses the same question as a set of rate level thresholds, and the distribution it implies is a touch more centered on no change. Neither venue is a prediction; both are a price, and the gap between them is information in its own right.

The situs of the disagreement matters for the next two weeks. The October meeting is a live event on Kalshi with a close time of 2026-10-28T17:55Z, and the ladder's shape suggests participants see the balance of risk tilted toward holding through October and reassessing at the December meeting. A hot core print like the one just resolved, plus a 10 year Treasury near 5.19%, keeps a November or December hike priced, but the October threshold pricing does not look like a market braced for an imminent move.

Related reading: Kalshi CPI Ladder: The 0.5% Threshold Slips to 58.5% as Neighboring Brackets Narrow.

The calibration takeaway is worth stating plainly. A single settled print measures one market at one moment, not its forecasting skill. The Buffalo Bills win market at 39% that settled YES two days after this desk filed its track record entry, and now the CPI ladder that resolved across four monthly thresholds, both settle correctly at the boundaries the underlying data dictated. Ladder structures, where a single release resolves several contracts at once, are where event market calibration is actually observable, and the September CPI ladder was a clean case: three of its settled outcomes matched the bracket math exactly.

The next dated event on the calendar is the October FOMC decision on October 28, followed by the December meeting. The desks will track those thresholds as they move. For retail readers, the honest framing is that these contracts are expectations markets, not recommendations, and the spread between Kalshi's level screen and Polymarket's hold screen is the most useful number to watch between now and the decision.

Related reading: September FOMC: Kalshi's Rate Ladder Priced the Hike at 87 Percent and Missed by Two Cents.

Disclosure: this piece is analysis of prediction market odds and movements only. It is not a recommendation to buy or sell any contract, and prediction market prices are not forecasts of future events. This content is for informational purposes only and does not constitute financial advice. Past performance is not indicative of future results. Consult a qualified financial advisor before making investment decisions.

Resolutions

Kalshi KXCPI-26SEP-T0.4, September CPI above 0.4%, settled YES after BLS reported a 0.59% monthly rise.

Kalshi KXCPI-26SEP-T0.5, September CPI above 0.5%, settled YES after BLS reported a 0.59% monthly rise.

Kalshi KXCPI-26SEP-T0.6, September CPI above 0.6%, settled NO because the 0.59% print did not clear the threshold.

Kalshi KXCPI-26SEP-T0.7, September CPI above 0.7%, settled NO because the 0.59% print did not clear the threshold.

Kalshi KXCPIYOY-26SEP-T3.6, September CPI year over year above 3.6%, settled YES after BLS reported 3.74%.