Every upcoming MLB fixture on Polymarket and every forecastable market on it — the whole board, no per-fixture cap. 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 MLBmarket the favorite-longshot backtest could reconstruct point-in-time from Polymarket's price history: 10,213 markets across 361 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 0.70c — the price is the probability.
market price
n
actually won
gap
0.085
26
0.154
+0.069
0.159
1,265
0.173
+0.014
0.248
2,114
0.258
+0.010
0.399
4,303
0.403
+0.003
0.578
1,827
0.586
+0.008
0.755
674
0.760
+0.005
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.
No 57¢
Spread -2.5Yes 33¢No 68¢
Spread -1.5Yes 28¢No 73¢
Spread -2.5Yes 19¢No 82¢
$379.4k within 2¢8/8 tradeable
No 66¢
Spread -1.5Yes 38¢No 63¢
Spread -2.5Yes 28¢No 73¢
Spread -2.5Yes 27¢No 75¢
$450.3k within 2¢8/8 tradeable
No 62¢
Spread -1.5Yes 30¢No 71¢
Spread -2.5Yes 28¢No 73¢
Spread -2.5Yes 22¢No 80¢
$347.5k within 2¢8/8 tradeable
No 58¢
Spread -1.5Yes 28¢No 73¢
Spread -2.5Yes 20¢No 83¢
Spread -2.5Yes 33¢No 68¢
$432.1k within 2¢8/8 tradeable
No 64¢
Spread -1.5Yes 34¢No 67¢
Spread -2.5Yes 27¢No 74¢
Spread -2.5Yes 24¢No 77¢
$279.8k within 2¢8/8 tradeable
No 55¢
Spread -2.5Yes 36¢No 65¢
Spread -1.5Yes 26¢No 75¢
Spread -2.5Yes 19¢No 82¢
$282.3k within 2¢8/8 tradeable
No 66¢
Spread -2.5Yes 26¢No 75¢
Spread -1.5Yes 34¢No 67¢
Spread -2.5Yes 25¢No 77¢
$275.7k within 2¢8/8 tradeable
No 80¢
Spread -1.5Yes 40¢No 61¢
Spread -1.5Yes 31¢No 70¢
Spread -2.5Yes 30¢No 71¢
$277.0k within 2¢8/8 tradeable
No 62¢
Spread -2.5Yes 29¢No 72¢
Spread -1.5Yes 29¢No 72¢
Spread -2.5Yes 20¢No 81¢
$396.0k within 2¢8/8 tradeable
No 57¢
Spread -2.5Yes 19¢No 82¢
Spread -2.5Yes 32¢No 69¢
Spread -1.5Yes 27¢No 74¢
$254.2k within 2¢8/8 tradeable
No 72¢
Spread -1.5Yes 44¢No 57¢
Spread -2.5Yes 22¢No 80¢
Spread -2.5Yes 35¢No 66¢
$378.4k within 2¢8/8 tradeable
No 64¢
Spread -2.5Yes 28¢No 73¢
Spread -1.5Yes 34¢No 67¢
Spread -2.5Yes 24¢No 78¢
$206.4k within 2¢8/8 tradeable
No 61¢
Spread -2.5Yes 20¢No 82¢
Spread -1.5Yes 29¢No 72¢
Spread -2.5Yes 30¢No 71¢
$248.9k within 2¢8/8 tradeable
Yes 49¢
No 52¢
TotalsO/U 5.5Yes 99¢No 50¢
TotalsO/U 6.5Yes 99¢No 47¢
TotalsO/U 10.5Yes 48¢No 99¢
Spread -1.5Yes 44¢No 58¢
Spread -3.5Yes 42¢No 99¢
Spread -1.5Yes 38¢No 72¢
Spread -2.5Yes 50¢No 92¢
Spread -2.5Yes 80¢No 93¢
Spread -3.5Yes 91¢No 97¢
Spread -4.5Yes 91¢No 97¢
$22.6k within 2¢3/15 tradeable
Back the favorite — the one rumoured edge
Buy every favorite priced ≥ 70c, net of ~2c cost, significance clustered by fixture. In MLB moneylines it comes to too few high-priced favorites to test honestly — across all market types, −3.42c (t = -0.67). Null after cost — no free structural edge here either.
market type
bets
fixtures
net edge
t (clustered)
Moneyline
—
—
—
—
Totals
675
195
−3.15c
-0.55
Both teams to score
—
—
—
—
Spread
—
—
—
—
All types
678
195
−3.42c
-0.67
“—” 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.
