Every upcoming NFL fixture on Polymarket and every forecastable market on it — the whole board, uncapped. Keyless, live, cached a few minutes. A market is tradeable when its spread is ≤ 5¢ and ≥ $100 sits within 2¢ of the ask.
Every resolved NFLmarket the favorite-longshot backtest could reconstruct point-in-time from Polymarket's price history: 2,679 markets across 580 fixtures. The question is whether the market itself is mispriced — buy every favorite and win. It isn't, and you don't.
Calibration — is the price the probability?
Each bucket: what the market charged, versus how often it actually happened. The gap averages 2.62c — the price is the probability.
market price
n
actually won
gap
0.153
53
0.094
−0.059
0.257
147
0.231
−0.025
0.438
1,285
0.456
+0.018
0.555
1,081
0.586
+0.030
0.749
98
0.673
−0.076
Back the favorite — the one rumoured edge
Buy every favorite priced ≥ 70c, net of ~2c cost, significance clustered by fixture. In NFL moneylines it comes to −5.61c per $1 (t = -0.75). Negative after cost, and nowhere near significant — no free structural edge.
Everything here is generated from public market data and provided for information only. It is not betting advice, not a recommendation to wager, and not a claim that any edge exists. Live prices move; the snapshot is minutes old by the time you read it.
— across all market types, −7.42c (t = -1.17)
market type
bets
fixtures
net edge
t (clustered)
Moneyline
88
84
−5.61c
-0.75
Totals
—
—
—
—
Both teams to score
—
—
—
—
Spread
14
11
−32.39c
-1.89
All types
104
94
−7.42c
-1.17
“—” means fewer than 8 favorites of that type — too thin to test. A real edge would need net > 0 andt > ~2.5 in a type that isn't just near-certain totals, and would have to survive out-of-sample.
