Kalshi vs Polymarket on ATP tennis matches: where the prices disagree today
5 ATP tennis matches priced on both Kalshi and Polymarket right now, $233k traded in 24 hours. The widest disagreement is Alexander Blockx at 0.0 pp. Updated every 45 seconds.
| Event | Outcome | Kalshi | Polymarket | Gap (K − P) | Net edge | |
|---|---|---|---|---|---|---|
| US Open ATP: Francisco Cerundolo vs Alexander Blockx Sep 7, 11:00 AM ET | Alexander Blockx | 60¢ | 60¢ | 0.0 pp | -3.20¢ | Kalshi · Polymarket |
| US Open ATP: Alex Michelsen vs Tomas Etcheverry Sep 6, 2:30 PM ET | Alex Michelsen | 73¢ | 74¢ | -1.0 pp | -2.99¢ | Kalshi · Polymarket |
| US Open ATP: Ben Shelton vs Stefanos Tsitsipas Sep 6, 7:00 PM ET | Ben Shelton | 70¢ | 70¢ | 0.0 pp | -4.07¢ | Kalshi · Polymarket |
| US Open ATP: Daniil Medvedev vs Frances Tiafoe Sep 6, 3:00 PM ET | Daniil Medvedev | 59¢ | 59¢ | 0.0 pp | -4.21¢ | Kalshi · Polymarket |
| US Open ATP: Tommy Paul vs Carlos Alcaraz Sep 6, 2:00 PM ET | Carlos Alcaraz | 84¢ | 84¢ | 0.0 pp | -2.67¢ | Kalshi · Polymarket |
How this is built
Every event listed on both exchanges is matched outcome by outcome: games by team codes and date, multi-outcome markets by name. Prices are mid-market: Polymarket from its live order book, Kalshi from its public API. Gap is Kalshi minus Polymarket in percentage points. Thin books (spread over 10¢) and near-certain favorites are excluded from this table.
Net edge
Buy one side on one venue and the other side on the other, both at the ask. Edge is $1 minus total cost minus taker fees, Kalshi ⌈0.07·P·(1−P)⌉ per contract and Polymarket 0.05·P·(1−P) on sports. Not advice; nothing here places orders.
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