Kalshi vs Polymarket on ATP tennis matches: where the prices disagree today
19 ATP tennis matches priced on both Kalshi and Polymarket right now, $742k traded in 24 hours. The widest disagreement is Nikoloz Basilashvili at +$0.01. Updated every 45 seconds.
| Event | Outcome | Kalshi | Polymarket | Gap, + = Kalshi higher | Edge after fees | |
|---|---|---|---|---|---|---|
| Almaty Open: Facundo Acosta vs Nikoloz Basilashvili Oct 21, 4:00 AM ET | Nikoloz Basilashvili | $0.68 | $0.67 | +$0.01 | -3.11% | Kalshi · Polymarket |
| Almaty Open: Adrian Mannarino vs Andrey Rublev Oct 21, 5:30 AM ET | Andrey Rublev | $0.77 | $0.76 | +$0.01 | -2.91% | Kalshi · Polymarket |
| European Open: Mariano Navone vs Tallon Griekspoor Oct 21, 7:00 AM ET | Tallon Griekspoor | $0.61 | $0.61 | $0.00 | -3.19% | Kalshi · Polymarket |
| Lyon Open: Corentin Moutet vs Felix Balshaw Oct 21, 9:30 AM ET | Felix Balshaw | $0.54 | $0.53 | +$0.01 | -3.25% | Kalshi · Polymarket |
| Almaty Open: Mattia Bellucci vs Tomas Etcheverry Oct 21, 2:35 AM ET | Mattia Bellucci | $0.56 | $0.56 | $0.00 | -4.23% | Kalshi · Polymarket |
| Almaty Open: James Duckworth vs Luciano Darderi Oct 21, 2:35 AM ET | Luciano Darderi | $0.52 | $0.52 | $0.00 | -4.25% | 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, in dollars on a contract that pays $1 if the outcome happens: Polymarket from its live order book, Kalshi from its public API. Gap is Kalshi minus Polymarket. Thin books (spread over $0.10) and near-certain favorites are excluded from this table.
Edge after fees
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, as a percent of the $1 payout. Not advice; nothing here places orders.
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