Polymarket$2.32BOIOpen interest: sum of pool liquidity across all active markets, reported by the Polymarket API.
Kalshi$350.67MOIOpen interest: total contracts outstanding across all active markets, reported by the Kalshi API.
Limitless$18.48MOIOpen interest: estimated from total volume traded (USDC). Limitless does not report a separate OI metric.Compare 2026 National League Championship prediction market odds side by side across Polymarket, Kalshi. Platforms show similar odds, with an average spread of just 0.8pp. Close agreement often signals strong market consensus. With $7.3K in combined trading volume across 15 outcomes, this is one of the notable cross-platform prediction markets.
Pittsburgh PiratesKalshiPolymarketCost: 97¢ per pair → pays $1 at resolution. Gross spread 3.2pp before fees.
View all arbs| Outcome | Polymarket | Kalshi | Spread |
|---|---|---|---|
Los Angeles Dodgers | 42%-0.5 | 43%±0 | 1.0pp spread |
New York Mets | 12%— |
12%+1.0 |
| 0.5pp spread |
Philadelphia Phillies | 10%+0.5 | 11%+1.0 | 1.0pp spread |
Chicago Cubs | 9%— | 9%±0 | 0.5pp spread |
Atlanta Braves | 8%— | 7%±0 | 1.0pp spread |
Milwaukee Brewers | 5%+0.5 | 6%±0 | 1.3pp spread |
San Diego Padres | 5%— | 5%±0 | 0.4pp spread |
Pittsburgh Pirates | 6%— | 3%±0 | 3.2pp spread |
San Francisco Giants | 3%-0.7 | 4%±0 | 0.5pp spread |
Arizona Diamondbacks | 2%±0 | 3%±0 | 0.8pp spread |
Cincinnati Reds | 2%±0 | 3%±0 | 1.1pp spread |
Colorado Rockies | 1%±0 | 1%±0 | 0.1pp spread |
St. Louis Cardinals | 1%+1.2 | 1%±0 | 0.3pp spread |
Miami Marlins | 1%±0 | 1%±0 | 0.5pp spread |
Washington Nationals | 0%+3.4 | 1%±0 | 0.6pp spread |
