July Inflation US - Monthly

Platform comparison

Market context

The Bureau of Labour Statistics will release the seasonally adjusted Consumer Price Index for July 2026 on 12 August 2026 at 8:30 AM ET. This monthly figure measures the one-month percentage change in prices paid by urban consumers across the full basket of goods and services. The current 0% implied probability across prediction platforms suggests traders expect either a flat reading or are pricing in extreme uncertainty ahead of the release. Comparing book structures, Polymarket displays this as a binary YES/NO contract with decimal odds conversion, whilst Kalshi typically offers tighter spreads on US economic data through its regulated derivatives framework. Betfair and Smarkets present fractional odds natively, which can obscure the precise probability threshold at which the market settles.

Monthly CPI changes have historically ranged between −0.1% and +0.8% in the post-pandemic period, with most readings clustering between 0.2% and 0.5%. The six-month trend through early 2026 showed disinflation momentum, though seasonal adjustments in summer months can produce volatile month-on-month swings. A flat or negative reading would align with the disinflationary narrative that has dominated Federal Reserve communications since late 2023.

Traders should monitor energy prices and wage growth data released in the weeks before 12 August, as both drive the final CPI print. The Producer Price Index report (scheduled mid-August) will arrive after settlement, so it offers no predictive edge. Fee structures vary materially: Polymarket charges 2% on net profits, Kalshi takes 0.5% per side, and Betfair's commission scales with volume. On a low-liquidity economic data market, fee drag becomes meaningful for small positions.

Methodology

We read July Inflation US - Monthly from four platform perspectives: Polymarket (on-chain CLOB), Kalshi (CFTC-regulated exchange), Betfair Exchange (sports book exchange), Smarkets (peer-to-peer betting exchange). Polymarket's live mid is the canonical probability; the side-by-side columns benchmark fees, KYC, settlement currency and deposit rails so you can choose the venue that fits your jurisdiction and trade size.

Resolution & payout

Settlement is the biggest difference between the four platforms: Polymarket on-chain in USDC (instant), Kalshi USD via CFTC (T+1), Betfair and Smarkets in local currency via bank withdrawal (T+1 to T+3). On-chain settlement clears in minutes — the fastest payout path of the four.

FAQ

What does Polymarket cost vs Kalshi?

Polymarket: 0% fees, only Polygon network costs (~$0.01/trade). Kalshi: up to 7% per trade plus spread. For high-frequency traders, Polymarket is dramatically cheaper.

Which platform has the deepest liquidity?

Polymarket — by a wide margin. Top markets reach $50-500M volume, Kalshi ~$200M cumulative, Betfair similar. Deeper liquidity means your trade moves the quote less.

What about Smarkets as an alternative?

Smarkets is a UK betting exchange with a lower default commission (2%) than Betfair. Liquidity on political markets is below Polymarket, comparable to Kalshi. Geo-blocked in many jurisdictions.

Which platform is accessible globally?

Polymarket is geo-blocked in the US/UK/EU. Kalshi is US-only. Betfair and Smarkets are UK-restricted. Robinhood Prediction Markets has a different geo footprint and routes to Polymarket's order book at 0% fees.

Which platform supports Klarna/SOFORT?

Directly: none. Polymarket accepts only USDC on Polygon. Robinhood Prediction Markets offers a fiat on-ramp via Klarna or SOFORT (DE/AT/CH) and converts internally to USDC for the Polymarket order book. T+1 processing.