August 2026 CPI Report (Sept 11 Release): Core CPI 0.3% MoM, 2.4% YoY
The BLS released August 2026 CPI data on Friday, September 11 at 8:30 a.m. ET: headline +0.4% MoM and +3.4% YoY, core CPI +0.3% MoM and +2.4% YoY. How the Polymarket markets settled, the Fed repricing, and the October 14 next release are below.
Published July 18, 2026 · Substantially updated September 11, 2026 (post-release) · Next CPI: October 14, 2026 · Next planned refresh: October 12, 2026 (pre-release)
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The August 2026 CPI report was released Friday, September 11, 2026 at 8:30 a.m. ET (release USDL-26-1496): headline CPI rose +0.4% month over month and +3.4% year over year; core CPI rose +0.3% MoM and +2.4% YoY. Gasoline (+3.9%) accounted for over a third of the monthly all-items increase. At the September 11, 14:01 UTC snapshot, Polymarket’s August core CPI markets had settled in trading to the 0.3% MoM and 2.4% YoY buckets at 99.95¢ — the YoY favorite (46¢) won, while the MoM favorite 0.2% (55.5¢ on September 8) lost to a hotter print. The next CPI report is Wednesday, October 14, 2026, covering September data. The full print, settlement tables, and the Fed repricing to 80.5¢ on a hike are below.
August 2026 results: the official print and how the markets settled
The BLS released the August 2026 Consumer Price Index on Friday, September 11 at 8:30 a.m. ET (release USDL-26-1496; checked September 11, 2026 at 14:02 UTC). Four published values anchor every CPI market that resolves from this report:
Headline CPI MoM
+0.4%, seasonally adjusted, after +0.1% in July. Gasoline rose 3.9% and accounted for over one third of the monthly all-items increase; energy rose 2.1%.
Headline CPI YoY
+3.4%, before seasonal adjustment — unchanged from July. Energy is up 16.3% over the 12 months ending August; food is up 2.7%.
Core CPI MoM
+0.3%, seasonally adjusted, after +0.2% in July. This is the series the Polymarket month-over-month market resolves on; it came in one tenth above the 0.2% favorite.
Core CPI YoY
+2.4%, before seasonal adjustment, down from +2.5% in July — matching the bucket the year-over-year market had priced as its favorite.
Settlement pricing (14:01 UTC snapshot, ~90 minutes after the print)
Both August core CPI event groups moved to a resolved pricing pattern within minutes of the 8:30 a.m. ET print. The tables below are a timestamped snapshot taken September 11, 2026 at 14:01 UTC; both groups remained technically open pending official settlement at that moment. “Displayed Yes” is the last traded price; losing buckets sit at the 0.05¢ display floor.
Core CPI month over month — August 2026 (settled to 0.3%)
| Outcome bucket | Displayed Yes (post-print) | Bucket volume |
|---|---|---|
| 0.3% — printed value | 99.95¢ | $12,635 |
| 0.2% (September 8 favorite at 55.5¢) | 0.05¢ | $20,054 |
| 0.4% | 0.05¢ | $8,066 |
| 0.1% | 0.45¢ | $7,718 |
| 0.0% or less | 0.05¢ | $5,598 |
| 0.5% | 0.05¢ | $3,750 |
| 0.6% or more | 0.05¢ | $2,223 |
Event totals at the snapshot: $60,044 cumulative volume · $131,867 liquidity. View the month-over-month event →
Core CPI year over year — August 2026 (settled to 2.4%)
| Outcome bucket | Displayed Yes (post-print) | Bucket volume |
|---|---|---|
| 2.4% — printed value | 99.95¢ | $17,006 |
| 2.5% (September 8: 13¢) | 0.05¢ | $5,262 |
| 2.3% (September 8: 26.5¢) | 0.05¢ | $3,042 |
| 2.6% | 0.05¢ | $2,745 |
| 2.2% | 0.05¢ | $2,063 |
| 2.7% | 0.05¢ | $1,432 |
| 2.8% | 0.05¢ | $1,360 |
| 2.1% | 0.05¢ | $845 |
| 2.0% or less | 0.05¢ | $781 |
| 2.9% or more | 0.05¢ | $870 |
Event totals at the snapshot: $35,405 cumulative volume · $150,699 liquidity. View the year-over-year event →
The favorite that lost
The month-over-month market had priced 0.2% as the favorite (55.5¢ on September 8) — and 0.2% was also the most-traded bucket at $20,054 in lifetime volume. The printed 0.3% had been the 35¢ second favorite. A favorite losing is a normal market outcome, not a malfunction: prices are odds, not guarantees.
The YoY favorite won
The year-over-year market’s 2.4% favorite (46¢ on September 8, $17,006 bucket volume) matched the printed value after core inflation cooled from 2.5% to 2.4% on an annual basis — the gradual-disinflation path the board had priced most likely.
No September-reference market listed yet
At this update no core CPI event group for the October 14 release (September reference month) had been listed on the recurring series. When one appears it is a new, separate contract window — this page will cover it in the October 12 pre-release refresh.
Official July 2026 CPI results published August 12
Headline CPI MoM
+0.1%, seasonally adjusted. Up from −0.4% in June. Shelter accounted for roughly two-thirds of the monthly increase; energy declined 1.5%.
Headline CPI YoY
+3.4%, before seasonal adjustment. Down from +3.5% in June. Energy rose 14.7% over the 12 months ending July, while food increased 3.0%.
Core CPI MoM
+0.2%, seasonally adjusted. Up from 0.0% in June. Medical care, airline fares, communication, education, and recreation increased; motor vehicle insurance decreased.
Core CPI YoY
+2.5%, before seasonal adjustment. Down from +2.6% in June. This is the same series family named by the reviewed year-over-year prediction market.
Polymarket core CPI markets: resolution summary
Both July core CPI event groups on Polymarket resolved to the matching outcome buckets after the BLS release. A Gamma API check on August 12, 2026 around 14:00 UTC confirmed all winning buckets traded at 99.95 cents (Yes) and all other buckets at 0.05 cents (No). Markets remained technically open pending official settlement but the pricing reflects a resolved outcome.
Core CPI MoM — 0.2% bucket wins
The 0.2% outcome bucket attracted the highest individual market volume at $56,808, well ahead of 0.3% ($39,842) and 0.1% ($38,444). Total event volume reached $173,068 with $298,764 in liquidity across all seven buckets.
Core CPI YoY — 2.5% bucket wins
The 2.5% outcome bucket won with $19,032 in individual volume. Total event volume reached $139,959 with $331,470 in liquidity across all ten buckets. The 2.4% bucket ($45,352) was the most-traded non-winning outcome, followed by 2.7% ($20,828).
Combined, the two event groups represented roughly $313,027 in cumulative volume and $630,234 in liquidity at the August 12 post-release snapshot — a substantial increase from the $187,336 cumulative volume recorded in the August 9 pre-release check.
What the August print means for the September Fed meeting
A hotter core print than priced
Core CPI rose 0.3% month over month — one tenth above both July’s reading and the market’s 0.2% favorite. The annual core rate still edged down, from 2.5% to 2.4%, but the monthly acceleration matters for a Fed weighing a hike.
The Fed board repriced hard
At the September 11, 14:01 UTC snapshot — roughly 90 minutes after the print — the September Fed decision event showed 80.5¢ on a 25-basis-point hike versus 18.5¢ on no change, with $123.0 million in cumulative volume and $10.8 million traded in 24 hours. On September 8 the same board was a near coin-flip (52.5¢ hike / 46.5¢ hold).
Energy pushed the headline
Gasoline (+3.9% MoM, +27.4% YoY) and energy (+2.1% MoM, +16.3% YoY) drove the 0.4% headline print. Energy is excluded from core CPI, which is why the headline and core monthly numbers diverged this month.
What settles it
The September 15–16 FOMC decision arrives five days after this print. The Fed event resolves on the actual policy move, not on CPI itself — see the September FOMC guide for the board, rules, and calendar, and the October 27–28 Fed meeting guide for the meeting after.
Remaining 2026 CPI release timeline
8:30 a.m. ET. Headline +0.1% MoM, +3.4% YoY. Core +0.2% MoM, +2.5% YoY. Both Polymarket core CPI markets resolved to winning buckets.
BLS schedule re-verified for the September 11 release; live August core CPI market snapshot added at 14:04 UTC, three days out.
8:30 a.m. ET. Headline +0.4% MoM, +3.4% YoY; core +0.3% MoM, +2.4% YoY. Both Polymarket core CPI markets settled in trading to 0.3% and 2.4%; this post-release update shipped the same day (~14:05 UTC).
8:30 a.m. ET, Wednesday. A new reference month and a separate contract window from the August release. Falls two weeks after the September 30 federal funding deadline — during the 2025 shutdown the Labor Department suspended BLS data releases (see the government shutdown October 2026 guide). A pre-release refresh is planned on this page around October 12.
8:30 a.m. ET, one week after the November 3 U.S. midterm election. Political timing does not alter the CPI series or its source.
8:30 a.m. ET. This is the final CPI publication listed on the BLS calendar for calendar year 2026.
June 2026 baseline (prior month for comparison)
The June release (published July 14) supplies the comparison point for July. These four figures use different seasonal and comparison conventions, so they should not be blended into one generic "inflation number."
Headline CPI, month over month
−0.4%, seasonally adjusted. BLS said the all-items decline was the largest one-month decrease since April 2020, with a 5.7% fall in the energy index the largest contributor.
Headline CPI, 12 months
+3.5%, before seasonal adjustment. This was the all-items change over the 12 months ending June.
Core CPI, month over month
0.0%, seasonally adjusted. "Core" here means all items less food and energy. This was the same series family named by the July month-over-month market.
Core CPI, 12 months
+2.6%, before seasonal adjustment. Down from +2.5% in July, showing the annual core rate fell over the month.
How the two core CPI events differed
One-month change
The month-over-month event used the seasonally adjusted change in core CPI-U from June to July. It asked how much the index changed over one month after the seasonal adjustment specified in the rules. Answer: 0.2%.
Twelve-month change
The year-over-year event used the change in core CPI-U over the 12 months ending July before seasonal adjustment. It did not ask for the one-month figure annualized. Answer: 2.5%.
Same release, different cells
Both events named the August 12 BLS report, but they resolved from different values in that report. A correct answer to one contract did not determine the other.
One-decimal precision
Both rule sets say BLS reports the relevant core measure to one decimal point and that this is the precision used for resolution. More precise private estimates do not replace the published value.
CPI market resolution: eight distinctions that matter
1. CPI-U is specified
The reviewed events use the Consumer Price Index for All Urban Consumers. CPI-W, chained CPI, PCE inflation, producer prices, and private inflation estimates are different series.
2. Core is not headline
Both reviewed events specify all items less food and energy. The headline all-items number can move differently and cannot substitute for core CPI at settlement.
3. MoM and YoY use different comparisons
The one-month event compares July with June on a seasonally adjusted basis. The 12-month event compares July with July a year earlier before seasonal adjustment.
4. July is the reference month
The data month is July even though the release date is August 12. Record both fields so an August-release question is not confused with August data due in September.
5. Precision is one decimal
The rule text explicitly ties resolution to BLS one-decimal reporting. A model or newswire carrying more decimals is not the named resolution source.
6. Edge buckets are inclusive
The first and last buckets use "or less" and "or more." Middle buckets are exact one-decimal values. Check the actual group title rather than inferring boundaries from a chart.
7. The official BLS release controls
Both events name the monthly BLS CPI news release and say resolution takes place when the data is released. Commentary, consensus surveys, and market prices are supporting context only.
8. Delay fallback is explicit
If BLS does not release the relevant figure on schedule, the rules allow the market to remain open until the next CPI release time; if the figure is still unavailable, they point to the most recent prior month with available data.
A repeatable CPI research workflow
Verify the release clock
Start with the live BLS schedule, record the reference month, and account for Eastern Time. Do not rely on a recycled calendar graphic.
Name the exact series
Write down CPI population, headline or core, comparison period, seasonal treatment, precision, and official source before opening an order book.
Read every outcome label
List the low edge, exact middle buckets, and high edge. Confirm inclusive wording and whether the market is one neg-risk group or separate binary books.
Timestamp market evidence
Capture bid, ask, spread, depth, volume, liquidity, and time together. Use the prediction-market odds guide before treating cents as a frictionless probability.
Map nearby catalysts separately
The 2026 jobs report calendar and September FOMC guide are useful context, but neither determines the CPI value or resolves these contracts. The October 27–28 Fed meeting guide extends the same calendar beyond September.
Keep the watchlist educational
The biggest-movers tool can flag repricing after the release. A move is a prompt to recheck facts, rules, and liquidity—not a recommendation.
Frequently asked questions
What was the August 2026 CPI report?
The BLS reported on September 11, 2026 that headline CPI rose 0.4% month over month and 3.4% year over year. Core CPI (all items less food and energy) rose 0.3% month over month and 2.4% year over year. Gasoline rose 3.9% in August, accounting for over a third of the monthly all-items increase.
How did the Polymarket August core CPI markets settle?
The Core CPI YoY market settled to its favorite, the 2.4% bucket (46 cents on September 8; 99.95 cents after the print). The Core CPI MoM market settled to 0.3% at 99.95 cents — the 0.2% favorite at 55.5 cents lost to a hotter print. Both groups remained technically open pending official settlement at the September 11, 14:01 UTC snapshot.
What was the July 2026 CPI report?
The BLS reported on August 12, 2026 that headline CPI rose 0.1% month over month and 3.4% year over year. Core CPI (all items less food and energy) rose 0.2% month over month and 2.5% year over year.
Did the Polymarket July core CPI prediction markets resolve correctly?
Yes. The July Core CPI MoM market resolved to the 0.2% bucket and the YoY market to the 2.5% bucket, both at 99.95 cents, with all other outcome buckets settling at No.
When is the next U.S. CPI report in 2026?
The next scheduled release is Wednesday, October 14, 2026 at 8:30 a.m. Eastern Time, covering September 2026 reference-month data.
What are the remaining 2026 CPI release dates?
The remaining scheduled dates are October 14, November 10, and December 10, all at 8:30 a.m. Eastern Time.
How does the August CPI report affect the September Fed meeting?
Core CPI came in hotter than the market favorite (0.3% versus 0.2% month over month). Roughly 90 minutes after the print, Polymarket’s September Fed decision event showed about 80.5 cents on a 25-basis-point hike versus 18.5 cents on no change — up from a 52.5/46.5 near coin-flip on September 8. The Fed decides September 15–16; that event resolves on the actual policy move, not on CPI itself.
Do CPI prediction markets resolve on headline or core CPI?
It depends on the contract. The events reviewed here specify core CPI-U, meaning all items less food and energy. A headline CPI value cannot be substituted for that series.
What is the difference between core CPI month over month and year over year?
The month-over-month event uses the seasonally adjusted change from the prior month. The year-over-year event uses the not-seasonally-adjusted change over the 12 months ending in the reference month. Both use one-decimal precision.
When will this 2026 CPI guide be refreshed again?
A pre-release refresh is planned for October 12, 2026, ahead of the October 14 release — including a check for newly listed September-reference markets — followed by a post-release update on October 14, 2026.
More live odds on this topic
📈 Every live Polymarket market on the topic: Inflation & CPI odds · Fed & Interest Rates odds
Sources and methodology
- BLS: Consumer Price Index Summary — August 2026 — official release USDL-26-1496, September 11, 2026. Headline +0.4% MoM / +3.4% YoY; core +0.3% MoM / +2.4% YoY; next release confirmed for October 14, 2026. Checked September 11, 2026 at 14:02 UTC.
- Polymarket Gamma: Fed decision — September 2026 — post-print snapshot September 11, 2026 at 14:01 UTC: +25bp bucket at 80.5¢, no-change 18.5¢; $123.0 million cumulative volume.
- BLS: Consumer Price Index Summary — July 2026 — official release USDL-26-1378, August 12, 2026. Headline and core values, monthly and 12-month changes, and sub-index detail. Checked August 12, 2026 at 14:00 UTC.
- BLS: Schedule of Releases for the Consumer Price Index — official reference months, release dates, and 8:30 a.m. ET times; checked September 11, 2026 (September reference month confirmed for October 14).
- BLS: Consumer Price Index Frequently Asked Questions — CPI scope, populations, seasonal adjustment, and methodology context.
- Polymarket Gamma: Core CPI MoM — July 2026 — post-release pricing confirms 0.2% bucket at Yes 99.95¢; $173,068 cumulative volume, $298,764 liquidity; checked August 12, 2026 at 14:00 UTC.
- Polymarket Gamma: Core CPI YoY — July 2026 — post-release pricing confirms 2.5% bucket at Yes 99.95¢; $139,959 cumulative volume, $331,470 liquidity; checked August 12, 2026 at 14:00 UTC.
- Polymarket Gamma: Core CPI MoM — August 2026 — post-release snapshot September 11, 2026 at 14:01 UTC: 0.3% bucket at 99.95¢ (the 0.2% favorite lost); $60,044 cumulative volume, $131,867 liquidity; official settlement pending.
- Polymarket Gamma: Core CPI YoY — August 2026 — post-release snapshot September 11, 2026 at 14:01 UTC: 2.4% bucket at 99.95¢ (the pre-release favorite); $35,405 cumulative volume, $150,699 liquidity; official settlement pending.
Next refresh: October 12, 2026 (pre-release check for the October 14 release, including whether September-reference Polymarket markets have been listed), then a post-release update on October 14 — or earlier if BLS changes the schedule.