How accurate are prediction markets?

In July 2026, 64% of the 39 highest-volume Polymarket markets resolved to the outcome that was priced above 50% a day before close, with a Brier score of 0.245.

What is a Brier score?

The average squared difference between the forecast probability and the outcome (1 if it happened, 0 if not). Lower is better; a constant 50% forecast scores 0.25.

Which markets are included?

Resolved Polymarket events with more than $50K of volume in the selected window, up to 40 per month, graded on the price one day and one week before close.

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Resolved markets

Prediction market scorecard: July 2026

For every high-volume market that resolved, we record what Polymarket priced the eventual outcome at one day and one week before close. This is the record, good and bad.

Updated 2026-11-06 01:50 UTC · Source: Polymarket · 18+

Last 30 days Nov 2026 Oct 2026 Sep 2026 Aug 2026 Jul 2026 Jun 2026

Favorites that won

64%

25 of 39 markets where the eventual result was priced above 50% a day before

Brier score (1 day out)

0.245

0 is perfect, 0.25 is a coin flip

Markets graded

highest-volume resolutions, July 2026

Resolved markets, July 2026

Market	Result	1 day before	7 days before	Volume
World Cup Winner resolved July 20, 2026	Spain	59.1%	20.6%	$4.33B
2026 NBA Champion resolved June 14, 2026	New York Knicks	80.8%	78.3%	$426.9M
Fed Decision in July? resolved July 29, 2026	No change	76.9%	76.6%	$144.0M
Spain vs. Argentina - More Markets resolved July 19, 2026	Argentina	80.1%	–	$85.9M
France vs. Spain - More Markets resolved July 14, 2026	Spain	80.4%	–	$78.2M
World Cup: Golden Boot Winner resolved July 20, 2026	Kylian Mbappe	93.5%	56.5%	$76.7M
Spain vs. Argentina - Exact Score resolved July 19, 2026	Spain 0 - 0 Argentina	10.5%	–	$66.4M
England vs. Argentina - More Markets resolved July 15, 2026	Argentina	84.9%	–	$65.6M
Belgium vs. Senegal resolved July 1, 2026	Draw (Belgium vs. Senegal)	29.5%	–	$59.7M
Norway vs. England - More Markets resolved July 11, 2026	England	91.1%	–	$59.4M
France vs. Morocco - More Markets resolved July 9, 2026	France	35.5%	–	$57.5M
Argentina vs. Egypt - More Markets resolved July 7, 2026	Egypt	56.5%	–	$57.0M
Mexico vs. England - More Markets resolved July 6, 2026	England	88.5%	–	$55.8M
France vs. Spain resolved July 14, 2026	Spain	29.9%	–	$52.0M
France vs. England - More Markets resolved July 18, 2026	England	70.5%	–	$51.2M
Canada vs. Morocco resolved July 4, 2026	Morocco	53.5%	–	$51.0M
Paraguay vs. France - More Markets resolved July 4, 2026	France	99.4%	–	$49.6M
Argentina vs. Cabo Verde resolved July 4, 2026	Draw (Argentina vs. Cabo Verde	11.5%	–	$49.0M
Norway vs. England resolved July 12, 2026	Draw (Norway vs. England)	26.1%	–	$48.2M
Spain vs. Argentina resolved July 19, 2026	Draw (Spain vs. Argentina)	31.6%	–	$47.1M
Switzerland vs. Colombia resolved July 7, 2026	Draw (Switzerland vs. Colombia	31.5%	–	$43.5M
Brazil vs. Norway - More Markets resolved July 5, 2026	Norway	71.5%	–	$43.3M
France vs. England resolved July 18, 2026	England	24.5%	–	$42.3M
United States vs. Belgium - More Markets resolved July 7, 2026	Belgium	83.5%	–	$42.1M
Argentina vs. Cabo Verde - More Markets resolved July 4, 2026	Cabo Verde	35.5%	–	$41.7M
Argentina vs. Egypt resolved July 7, 2026	Argentina	71.5%	–	$41.0M
Spain vs. Belgium resolved July 10, 2026	Spain	59.4%	–	$38.9M
Spain vs. Belgium - More Markets resolved July 10, 2026	Belgium	66.6%	–	$38.5M
Argentina vs. Switzerland - More Markets resolved July 12, 2026	Switzerland	69.6%	–	$38.5M
England vs. Argentina resolved July 15, 2026	Argentina	31.9%	–	$38.5M
Mexico vs. England resolved July 6, 2026	England	39.5%	–	$38.2M
Switzerland vs. Colombia - More Markets resolved July 7, 2026	Colombia	90.5%	–	$37.3M
Portugal vs. Spain - More Markets resolved July 6, 2026	Spain	91.5%	–	$36.7M
France vs. Morocco resolved July 9, 2026	France	62.5%	–	$35.6M
What price will Bitcoin hit in June? resolved June 2, 2026	↓ 70,000	–	–	$34.9M
Argentina vs. Switzerland resolved July 12, 2026	Draw (Argentina vs. Switzerlan	26.9%	–	$34.7M
Belgium vs. Senegal - More Markets resolved July 1, 2026	Senegal	78.5%	–	$33.5M
Netherlands Parliamentary Election resolved November 2, 2025	D66	99.4%	7.5%	$32.8M
England vs. Argentina - Exact Score resolved July 15, 2026	England 1 - 2 Argentina	7.5%	–	$32.1M
Portugal vs. Spain resolved July 6, 2026	Spain	50.5%	–	$32.1M

"1 day before" is the Polymarket price of the outcome that eventually happened, 24 hours before the market was closed for resolution. Brier score averages (1 - price)² over graded markets.

How to read the scorecard

Calibration, not hit rate, is the real test: a market is doing its job if outcomes priced at 70% happen about 70% of the time, which means favorites should lose roughly 30% of the time at that price. A Brier score near 0.1 across a month is strong; 0.25 is no better than a coin flip. Sample sizes here are small, so treat one month as a snapshot. Methodology and the full court and enforcement data live in the tracker and editorial standards.

Frequently asked questions

How accurate are prediction markets?: In July 2026, 64% of the 39 highest-volume Polymarket markets resolved to the outcome that was priced above 50% a day before close, with a Brier score of 0.245.
What is a Brier score?: The average squared difference between the forecast probability and the outcome (1 if it happened, 0 if not). Lower is better; a constant 50% forecast scores 0.25.
Which markets are included?: Resolved Polymarket events with more than $50K of volume in the selected window, up to 40 per month, graded on the price one day and one week before close.