Short Answer

Both the model and the market overwhelmingly agree that CPI in September will be Above -0.3%, with only minor residual uncertainty.

1. Executive Verdict

  • CPI Above -0.2% is likely, driven by modest shelter-led inflation by Q3 2026.
  • Labor market, wages, and producer prices most influence the September 2026 figure.
  • Volatile energy components are projected to exert a mild drag on the September CPI.

Who Wins and Why

Outcome Market Model Why
Above 0.6% 20.0% 10.1% While professional forecasters expect 2026 headline and core CPI inflation to average 3.5% and 2.9% respectively (Q4/Q4 basis), implying lower average monthly rates, persistent inflation concerns and sticky economic factors suggest the possibility of a higher single-month print, aligning with the debiased price. [4][5][6][7]
Above 0.4% 20.0% 10.1% The market's low probability (10.1%) for September CPI being above 0.4% aligns with professional forecasts projecting average monthly inflation rates for 2026 (0.24-0.29%) below this threshold [4,5,6,7], while general "persistent inflation concerns" [4,5,6,7] provide some rationale for a non-zero probability of an upside deviation.
Above 0.5% 20.0% 10.1% Significant upward pressure from energy or supply shocks would be needed for this outcome.
Above 0.3% 19.0% 11.7% While professional forecasts indicate 2026 annual inflation rates that imply monthly averages near the 0.3% threshold [4][5][6][7], suggesting the market's low probability for exceeding it could be fair, the persistent and sticky nature of inflation noted in the forecasts points to a higher likelihood of a monthly reading above 0.3%.
Above 0.0% 52.0% 51.4% A balance of economic factors suggests September's CPI could be flat or slightly positive.

Current Context

The U.S. Bureau of Labor Statistics will release the September 2026 CPI. The report is scheduled for October 14, 2026, at 8:30 a.m. ET [^]. Preceding this, the August 2026 CPI report is due on September 11, 2026, at 8:30 a.m. ET [^][^]. This August data holds particular significance, releasing five days before the Federal Open Market Committee (FOMC) meeting on September 16, 2026 [^]. The September FOMC meeting is a Summary of Economic Projections (SEP) meeting where the committee updates its economic forecasts and rate path expectations, influenced by incoming data such as the August CPI print [^].
Inflation expectations for 2026 remain elevated, though some indicators show moderation. Professional forecasters anticipate 2026 headline and core CPI inflation to average 3.5% and 2.9% respectively on a Q4/Q4 basis [^]. These forecasts reflect concerns that inflation may persist due to factors including tariff pressures, fiscal policy, and labor market conditions [^][^][^][^]. However, the Cleveland Fed's Q3 2026 survey of U.S. business leaders reported a projected CPI increase of 3.3% over the next 12 months, a decrease from their 3.7% forecast in April 2026 [^]. Similarly, the NY Fed’s July 2026 Survey of Consumer Expectations saw median one-year-ahead inflation expectations tick down by 0.1 percentage point to 3.6% [^]. Prediction markets currently show varying probabilities for core CPI outcomes, reflecting uncertainty in inflation trends [^]. The Cleveland Fed Inflation Nowcasting model provides real-time estimates for August 2026, but does not yet publicly display formal nowcasts for September 2026 [^].

2. Market Behavior & Price Dynamics

Historical Price (Probability)

Outcome probability
Date
This market's price has trended upward from a 3.0% starting probability, trading within a range of 2.0% to a high of 30.0%. The most significant price action was a sharp 18.0 percentage point spike on August 22, 2026, which moved the price from 2.0% to its current level of 20.0%. This repricing does not correspond to any specific news or data release identified in the provided context. The market appears to have established a new trading level around 20.0%, a significant departure from the low single-digit probabilities priced prior to this event.
Total volume stands at 53,322 contracts, but sample data indicates zero volume accompanied the price spike around August 22. This suggests the move occurred in a thin market and may not reflect broad conviction. Before the spike, the 2.0-3.0% range acted as a support level. The current 20.0% level now serves as the primary price point, with the prior high of 30.0% as potential resistance. The chart suggests a rapid shift in sentiment from a very low probability outcome to a roughly one-in-five chance, but the volume pattern implies this shift may be the result of a single or small set of trades rather than a widespread change in market expectation.

3. Significant Price Movements

Notable price changes detected in the chart, along with research into what caused each movement.

Outcome: Above 0.2%

📉 August 22, 2026: 75.0pp drop

Price decreased from 91.0% to 16.0%

What happened: The provided web research does not substantiate a 75.0 percentage point drop in the "CPI in September: Above 0.2%" prediction market on August 22, 2026 [^][^][^][^][^][^][^]. As of August 23, 2026, the September 2026 Consumer Price Index (CPI) had not been released, with its publication scheduled for October 14, 2026 [^][^]. Furthermore, no credible social media activity or traditional news reports correlating to such a specific and significant price movement for the September CPI market were found in the provided sources [^][^][^][^][^][^][^]. Therefore, the primary driver cannot be identified.

📈 August 20, 2026: 77.0pp spike

Price increased from 14.0% to 91.0%

What happened: The provided research does not support the existence of a "77.0 percentage point spike" in the prediction market for "CPI in September: Above 0.2%" on August 20, 2026 [^]. September 2026 CPI data would not have been released by this date, as the August 2026 CPI report is scheduled for September 11, 2026 [^]. No social media activity, traditional news, or market structure factors are evidenced as causes for such a movement on that date related to September CPI [^]. Given the lack of evidence for the event itself, social media is irrelevant to the described market movement.

📉 August 16, 2026: 59.0pp drop

Price decreased from 69.0% to 10.0%

What happened: The provided research does not identify a clear primary driver for the reported 59.0 percentage point drop in the "CPI in September: Above 0.2%" prediction market on August 16, 2026. Social media activity around August 16–17, 2026, primarily focused on legal trials and political rhetoric, showing no connection to September CPI expectations that would precipitate such a market movement [^][^][^]. Furthermore, official data for July 2026 CPI increased only 0.1% month-over-month, and there is no evidence of a 59.0 percentage point drop in inflation reported around this time [^][^]. Consequently, social media activity was irrelevant to this purported market movement.

Outcome: Above 0.5%

📉 August 19, 2026: 48.0pp drop

Price decreased from 98.0% to 50.0%

What happened: The provided research indicates no evidence of a 48.0 percentage point drop in the "CPI in September: Above 0.5%" prediction market occurring on August 19, 2026 [^]. The September 2026 CPI data is scheduled for release on October 14, 2026, meaning August 19, 2026, would be well in advance of the official data release [^][^]. The most recent CPI data available by August 19, 2026, was for July 2026, released August 12, 2026, which showed a 0.1% month-over-month increase and did not cause a 48pp shift on August 19 [^][^][^][^]. Therefore, without evidence of the specified price movement, its primary driver, including any social media activity, cannot be determined. Social media activity was likely irrelevant given the unsubstantiated nature of the reported price movement.

Outcome: Above 0.0%

📈 August 18, 2026: 44.0pp spike

Price increased from 54.0% to 98.0%

What happened: The reported "44.0 percentage point spike" in the "CPI in September: Above 0.0%" prediction market on August 18, 2026, appears to be based on a factual misunderstanding. Official data indicates no such national CPI spike, with the July 2026 CPI increasing only 0.1% monthly, and September 2026 CPI data not yet released on that date [^][^][^][^][^]. The "44.0 percent" figure likely refers to a regional gasoline price increase in St. Louis from April 2026, or a drop in September rate hike probabilities, which social media discussions may have misattributed to a national CPI spike [^][^][^]. Therefore, social media was mostly noise or irrelevant to an actual national CPI prediction market spike, as the underlying premise is unconfirmed by available data.

4. Market Data

Contract Snapshot

For this Kalshi prediction market on "CPI in September," a YES resolution occurs if the September Consumer Price Index (CPI) is above 0.4%. A NO resolution occurs if the September CPI is 0.4% or lower. The market begins in 51 days and is scheduled to settle by October 14, 6:30am EDT. No special settlement conditions are explicitly detailed in the provided content.

Available Contracts

Market options and current pricing

Outcome bucket Yes (price) No (price) Last trade probability
Above -0.2% $0.98 $0.27 99%
Above -0.3% $0.99 $0.28 98%
Above 0.1% $0.98 $0.39 97%
Above -0.1% $0.98 $0.25 75%
Above -0.4% $0.98 $0.29 72%
Above 0.0% $1.00 $0.49 52%
Above 0.4% $0.42 $0.63 20%
Above 0.5% $0.98 $1.00 20%
Above 0.6% $0.94 $0.97 20%
Above 0.3% $0.82 $0.77 19%
Above 0.2% $0.85 $0.71 16%

Market Discussion

Prediction markets as of August 23, 2026, reflect expectations for a positive month-over-month increase in September 2026 CPI, generally between 0.1% and 0.3% [^][^][^][^][^][^]. While specific September CPI forecasts and direct social media discussions are noted as absent from recent evidence, the Cleveland Fed's nowcasting model estimated August 2026 CPI at 0.35% monthly as of August 21, 2026, and consumer inflation expectations remained a key focus for policymakers in August 2026 [^][^][^][^][^][^][^][^][^][^][^][^]. Federal Reserve leadership has characterized inflation as "unquestionably too high" recently and projects a gradual decline to approximately 3.25% by the end of 2026 [^][^].

5. Trader Dashboard

A deterministic, per-market integrity scorecard computed from order-book and price data. Higher is better for Trader Trust, Liquidity, Move Quality and Resolution; higher means more risk for Quote Risk and Avoid Risk.

Above 0.6%PrimaryTrader Trust—Liquidity—Move Quality—Resolution—Quote Risk—Avoid Risk—
Move Quality—No significant movehigh confidence
  • Factor
Above -0.4%Trader Trust—Liquidity—Move Quality—Resolution—Quote Risk—Avoid Risk—
Move Quality—Insufficient Datainsufficient confidence
  • Factor
Above -0.3%Trader Trust—Liquidity—Move Quality—Resolution—Quote Risk—Avoid Risk—
Move Quality—Insufficient Datainsufficient confidence
  • Factor
Above -0.2%Trader Trust—Liquidity—Move Quality—Resolution—Quote Risk—Avoid Risk—
Move Quality—Insufficient Datainsufficient confidence
  • Factor
Above -0.1%Trader Trust—Liquidity—Move Quality—Resolution—Quote Risk—Avoid Risk—
Move Quality—Insufficient Datainsufficient confidence
  • Factor
Above 0.0%Trader Trust—Liquidity—Move Quality—Resolution—Quote Risk—Avoid Risk—
Move Quality—No significant movehigh confidence
  • Factor
Above 0.1%Trader Trust—Liquidity—Move Quality—Resolution—Quote Risk—Avoid Risk—
Move Quality—Insufficient Datainsufficient confidence
  • Factor
Above 0.2%Trader Trust—Liquidity—Move Quality—Resolution—Quote Risk—Avoid Risk—
Move Quality—No significant movehigh confidence
  • Factor
Above 0.3%Trader Trust—Liquidity—Move Quality—Resolution—Quote Risk—Avoid Risk—
Move Quality—No significant movehigh confidence
  • Factor
Above 0.4%Trader Trust—Liquidity—Move Quality—Resolution—Quote Risk—Avoid Risk—
Move Quality—No significant movehigh confidence
  • Factor
Above 0.5%Trader Trust—Liquidity—Move Quality78Resolution—Quote Risk—Avoid Risk—
Move Quality78Confirmedhigh confidence
  • Factor
  • Factor

trader_dashboard_lean_v1.13 · computed Aug 23, 2026

6. Which economic data releases between the August and September CPI reports will most influence the September 2026 inflation figure?

August 2026 CPI Report ReleaseSeptember 11, 2026 [^][^][^]
Most Influential DataLabor-market and wage data, then Producer Price Index (PPI) [^][^][^][^][^][^][^][^]
August 2026 PPI Report ReleaseSeptember 10, 2026 [^][^][^][^][^][^][^][^][^]
Labor market, wages, and producer prices most influence September 2026 inflation. The September 2026 inflation figure is primarily derived from the August 2026 Consumer Price Index (CPI) report, which the Bureau of Labor Statistics (BLS) is slated to release on September 11, 2026 [^][^][^]. Economic data releases between August 23, 2026, and this CPI report that are most likely to influence the inflation figure include labor-market and wage data, followed by the Producer Price Index (PPI) [^][^][^][^][^][^][^][^]. Highly influential labor-market and wage data consist of the August 2026 Employment Situation report, due September 4, 2026, and the July 2026 Job Openings and Labor Turnover Survey (JOLTS), scheduled for September 1, 2026 [^][^][^][^][^][^][^][^]. These releases, covering Nonfarm Payrolls, Average Hourly Earnings, and the unemployment rate, provide a broad macroeconomic signal for services inflation, given that wage growth affects labor-intensive categories and Federal Reserve policy expectations [^][^][^][^][^][^]. Furthermore, the August 2026 Producer Price Index (PPI) report, to be released on September 10, 2026, is a key upstream input for goods and some services prices, capable of directly altering expectations for the upcoming CPI [^][^][^][^][^][^][^][^][^].
Housing and consumer demand indicators also significantly shape the CPI outlook. Other important releases influencing the September 2026 CPI figure encompass housing-related indicators and consumer demand releases [^][^][^][^][^][^]. Housing constitutes the most significant CPI component by weight, making measures such as rent, owners’ equivalent rent proxies, building permits, housing starts, and new home sales highly relevant [^][^][^][^][^][^]. Consumer demand releases, including Retail Sales, consumer credit/spending indicators, and consumer sentiment, primarily impact the CPI through demand-side pressure on goods and discretionary services [^][^][^][^][^][^]. These indicators are also utilized by inflation forecasting models, such as those from the Cleveland Fed and the New York Fed, to project headline and core inflation trends [^][^][^].

7. What are the core arguments from economists for 'sticky' vs. moderating inflation scenarios for Q3 2026?

Q2 2026 Phila Fed Headline CPI Forecast3.50% Q4/Q4 basis (Q2 2026 Survey of Professional Forecasters [^])
Q2 2026 Phila Fed Core CPI Forecast2.90% Q4/Q4 basis (Q2 2026 Survey of Professional Forecasters [^])
August 2026 Headline CPI Monthly Change Nowcast0.35% (Cleveland Fed, as of August 21, 2026 [^])
Economists hold differing views on inflation's trajectory by Q3 2026. The debate primarily centers on the behavior of core and services components, including shelter and labor-sensitive categories [^]. Arguments for "sticky" inflation emphasize persistent service sector costs, such as shelter, and geopolitical tensions like the US-Iran conflict, which could contribute to stagflationary risks and energy price volatility [^]. Forecasters have notably revised up their inflation outlooks, with the Philadelphia Fed’s Q2 2026 Survey of Professional Forecasters expecting Q4/Q4 headline CPI at 3.50% and core CPI at 2.90%, both exceeding prior estimates [^]. Upward pressure from tariffs and their pass-through effects, as highlighted in the Fed’s July 2026 Monetary Policy Report, also supports the view that inflation will remain meaningfully above target [^].
Conversely, arguments for moderating inflation cite several influential factors. These include cooling goods prices as tariff impacts diminish, potential productivity gains from AI investments easing wage pressures, and a labor market showing signs of slower hiring and wage growth [^]. Firms anticipate a slowdown in cost growth and price increases in 2026, with year-ahead expectations returning to 2024 levels [^]. Recent monthly CPI readings, such as July's 0.10% month-over-month increase, annual CPI at 3.40%, and core CPI at 2.50%, are interpreted as consistent with continued disinflation rather than re-acceleration [^]. The Cleveland Fed's nowcasting for August 2026, suggesting a headline CPI monthly change of 0.35% [^], further supports a moderating trend without indicating a sharp acceleration that would necessitate immediate Federal Reserve tightening [^].

8. How do the Cleveland Fed's Nowcast and the NY Fed's consumer survey compare in their inflation outlooks for Q3 2026?

Cleveland Fed Q3 2026 CPI Nowcast1.22% (annualized rate) (as of August 21, 2026) [^]
Cleveland Fed Q3 2026 Core CPI Nowcast1.91% (annualized percent change) (as of August 21, 2026) [^]
NY Fed July 2026 Survey of Consumer Expectations (one-year-ahead)3.6% (July 2026) [^][^]
Direct comparison between the two inflation outlooks is challenging due to methodological differences. The Cleveland Fed's Inflation Nowcasting provides specific, short-term, data-driven projections for quarterly CPI [^]. As of August 21, 2026, its nowcast for Q3 2026 projects CPI inflation at an annualized rate of 1.22% and Core CPI at 1.91% [^]. These figures represent annualized percent changes for the quarter.
The New York Fed's survey provides longer-term household inflation expectations, which are not directly comparable to the Cleveland Fed's Q3 2026 nowcast [^] [^] [^] [^] [^] . The New York Fed's July 2026 Survey of Consumer Expectations (SCE) reported that median one-year-ahead inflation expectations decreased by 0.1 percentage point to 3.6% [^][^]. Expectations for three-year and five-year horizons remained unchanged, holding at 3.3% and 3.0%, respectively [^][^][^]. The SCE measures subjective household inflation expectations over these longer time frames [^][^].

9. When does the Bureau of Labor Statistics (BLS) collect the data for the September CPI, and what is its revision history?

CPI Data Collection PeriodSeptember 1–30, 2026 [^][^][^][^][^][^]
September 2026 CPI ReleaseOctober 14, 2026, at 8:30 A.M. ET [^][^]
Seasonally Adjusted CPI Revision PeriodUp to 5 years [^][^][^][^]
The Bureau of Labor Statistics collects September CPI data throughout the month. The Bureau of Labor Statistics (BLS) gathers data for the September 2026 Consumer Price Index (CPI) continuously from September 1–30, 2026, across three pricing periods to estimate the overall price level [^][^][^][^][^][^][^][^][^][^]. The BLS plans to release the September 2026 CPI on October 14, 2026, at 8:30 A.M. ET [^][^].
CPI revision policies vary for different index types. Standard CPI-U and CPI-W indexes are considered final upon their initial publication [^][^][^][^]. However, seasonally adjusted CPI indexes can be revised for up to 5 years [^][^][^][^]. The monthly headline CPI data generally does not undergo a standard revision process like some other economic indicators [^][^][^][^][^][^]. Conversely, specific sub-indexes, such as the Chained CPI-U (C-CPI-U), are initially released as preliminary and are subject to three quarterly revisions over a 10–12 month period [^][^][^][^][^][^].
Specific revision history for September 2026 CPI is not provided. The research does not include the BLS’s specific revision history for the September 2026 CPI, meaning it does not detail if or when this particular index would be revised after its initial publication [^][^][^][^][^][^]. To determine this revision history, explicit BLS documentation listing revisions for the September 2026 CPI would be necessary [^][^][^][^][^][^].

10. Based on Q3 2026 trends, what impact will volatile energy and shelter components have on the September CPI print?

Energy CPI Weight7% of CPI [^][^]
Shelter CPI Weight33% of CPI [^][^]
Shelter Contribution (July)Two-thirds of all-items increase in July [^][^][^][^][^][^][^][^]
Based on Q3 2026 trends, September CPI will likely see modest shelter-led inflation. Volatile energy components are projected to exert a mild drag or near-flat influence on the September 2026 Consumer Price Index (CPI) print, while shelter is anticipated to remain a modest but persistent positive contributor [^][^][^][^][^][^]. This suggests the September headline outcome will remain sensitive to fuel-price swings, but core inflation dynamics should still be predominantly shaped by shelter stickiness [^][^][^][^][^][^]. Prediction markets for September 2026 CPI currently indicate a lean toward a positive monthly increase, with probabilities favoring outcomes exceeding 0.1% and 0.2% monthly growth [^][^][^][^][^].
Energy’s volatility remains key despite recent mild September impact. Accounting for approximately 7% of the CPI weight, energy is a significant source of volatility and forecast error [^][^]. The energy index experienced considerable fluctuations, declining 1.5% in July 2026 after a 5.7% decline in June, primarily driven by gasoline [^][^][^][^][^][^][^][^]. Despite these recent monthly declines, energy prices remained elevated year-over-year, increasing 14.7% over the 12 months ending in July 2026 [^][^][^][^][^][^][^][^]. Energy prices, particularly gasoline, are highly sensitive to Middle East geopolitical tensions, meaning risks of a reversal and secondary inflationary impacts persist for the September print [^][^]. Consequently, any rebound in gasoline prices could swiftly negate the near-term drag on headline CPI [^][^][^][^][^][^].
Shelter will continue to drive core inflation due to its persistent growth. Representing roughly 33% of the CPI weight, shelter remains the most significant source of volatility and headline CPI forecast error [^][^]. The shelter index demonstrated persistent but moderate monthly growth, increasing 0.1% in both June and July 2026 [^][^]. It contributed approximately two-thirds of the all-items monthly increase in July [^][^][^][^][^][^][^][^]. Within the shelter category, owners' equivalent rent (OER) increased by 0.30% and rent by 0.30% in July [^][^][^][^][^][^]. Owners' equivalent rent continues to be relatively sticky, complicating the overall disinflation trajectory [^][^][^]. This small but positive monthly pace suggests shelter will likely continue to add upward pressure to both headline and core CPI through September, unless there is a clear step-down in the monthly rates for OER and rent [^][^][^][^][^][^].

11. What Could Change the Odds

Key Catalysts

The U.S. Bureau of Labor Statistics is scheduled to release the Consumer Price Index for August 2026 on September 11, 2026, at 8:30 A.M. Eastern Time [^][^][^]. The CPI for September 2026 is scheduled for release on Wednesday, October 14, 2026, at 8:30 A.M. Eastern Time [^][^][^]. Economic forecasts for 2026 indicate persistent inflation concerns, with predictions for higher-than-target headline and core CPI levels compared to previous years; the Federal Reserve is shifting focus toward price stability with potential rate tightening [^][^][^]. Economic sentiment in August 2026 showed U.S. business leaders decreased their 12-month inflation expectations to 3.3% in the third quarter of 2026, while consumer inflation expectations at the one-year-ahead horizon declined slightly to 3.6% in July 2026 [^][^]. The New York Fed's DSGE model, in its June 2026 forecast, projected core PCE inflation at 3.1% for 2026, identifying mark-up shocks as key factors [^].
Key market catalysts in September 2026 also include the FOMC meeting and rate decision, non-farm payrolls on September 4, and general volatility surrounding global geopolitical tensions affecting oil prices [^] [^] . The Treasury has doubled its long-end buyback cap from $2B to at least $4B per operation, which could weaken the dollar and support gold and U.S. equities [^][^][^][^][^][^][^][^]. This intervention is also framed as potentially reigniting tensions with the Fed and affecting yield dynamics, with discussions around rising term premium and higher coupons as debt supply increases [^][^][^][^][^][^][^][^]. Fed Chair Kevin Warsh's first Jackson Hole keynote on Friday the 28th also presents a general macro catalyst [^][^][^][^][^][^][^].

Key Dates & Catalysts

  • Expiration: January 13, 2027
  • Closes: October 14, 2026

12. Decision-Flipping Events

  • Trigger: The U.S.
  • Trigger: Bureau of Labor Statistics is scheduled to release the Consumer Price Index for August 2026 on September 11, 2026, at 8:30 A.M.
  • Trigger: Eastern Time [^] [^] [^] .
  • Trigger: The CPI for September 2026 is scheduled for release on Wednesday, October 14, 2026, at 8:30 A.M.

14. Historical Resolutions

Historical Resolutions: 19 markets in this series

Outcomes: 5 resolved YES, 14 resolved NO

Recent resolutions:

  • KXCPI-26JUL-T-0.4: YES (Aug 12, 2026)
  • KXCPI-26JUL-T-0.3: YES (Aug 12, 2026)
  • KXCPI-26JUL-T-0.2: YES (Aug 12, 2026)
  • KXCPI-26JUN-T-0.3: NO (Jul 14, 2026)
  • KXCPI-26JUN-T-0.2: NO (Jul 14, 2026)