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Kalshi / Polymarket / ProphetX

Iga Swiatek vs. Marta Kostyuk

WTA·2026-08-08

Best price · tap to trade

Marta Kostyuk77¢1.30x

Iga Swiatek22¢4.55x

About This Market

Traders give Marta Kostyuk about a 38.7% chance. Iga Swiatek follows at 60.9%. Compare prices from Kalshi, Polymarket, and ProphetX. The largest cross-platform price difference is 78.1 percentage points.

Iga Swiatek vs. Marta Kostyuk — WTA Tennis match scheduled for 2026-08-08. Compare live prediction market odds from Kalshi, Polymarket, and more on Prediction Hunt.

Learn more:How to Read Prediction Market Prices Compare Fees Before You Trade New to Polymarket?

Live Markets

3 platforms

Moneyline

OutcomeConsensus

Kalshi

Polymarket

ProphetX

Best price

Iga SwiatekARB

22%

100¢

22¢

4.58x22¢

Platform	Implied %	Yes bid / ask		No bid / ask
Kalshi	99.0%	0¢	100¢	0¢	100¢
Polymarket	—	100¢			0¢
ProphetX	21.9%	22¢	22¢	77¢	77¢

Marta Kostyuk

77%

100¢

77¢

1.29x77¢

Platform	Implied %	Yes bid / ask		No bid / ask
Kalshi	1.0%	0¢	100¢	0¢	100¢
ProphetX	77.4%	77¢	77¢	22¢	22¢

Kalshi

Polymarket

ProphetX

Best price among US-regulated venues.

Market RulebooksOfficial settlement criteria and edge cases

Official settlement criteria, resolution sources, and edge cases across Kalshi and Polymarket and ProphetX.

Rules for Candidate:

Kalshi

Primary Rule

If Marta Kostyuk wins the Kostyuk vs Swiatek professional tennis match in the 2026 WTA Toronto Round Of 16 after a ball has been played, then the market resolves to Yes.

Edge Cases

The following market refers to the Kostyuk vs Swiatek professional tennis match in the 2026 WTA Toronto Round Of 16 after a ball has been played. If the match does not occur (signaled by a ball being played) due to a player injury, walkover, forfeiture, or any other cancellation (all before the match starts), the market will resolve to a fair price in accordance with the rules. If this match is postponed or delayed, the market will remain open and close after the rescheduled match has finished (within two weeks). Kalshi is not affiliated, associated, authorized, endorsed by, or in any way officially connected with the Governing League. All trademarks, logos, and brand names are the property of their respective owners.

Resolution Oracles

Kalshi Rules

Polymarket

Primary Rule

This market refers to the tennis match between Marta Kostyuk and Iga Swiatek in the National Bank Open, originally scheduled for August 9, 2026 at 10:00AM ET. This market will resolve to 'Marta Kostyuk' if Marta Kostyuk advances against Iga Swiatek. This market will resolve to 'Iga Swiatek' if Iga Swiatek advances against Marta Kostyuk. If the match is canceled (not played at all), ends in a tie, or is delayed beyond 7 days from the scheduled date without a winner determined, this market will resolve to 50-50. If the match begins but is not completed, and one player advances due to the opponent's retirement, default, or disqualification, this market will resolve to the player who advances. If the match ends in a walkover (player withdraws before the start and the other advances automatically), this market will resolve to 50-50. The primary resolution source will be official information from the WTA Tour. A consensus of credible reporting may also be used.

Resolution Oracles

UMA Optimistic OracleConsensus of Sources

ProphetX

Primary Rule

Sports moneyline - resolves based on official game outcome per ProphetX Prediction Rules

Resolution Oracles

ProphetX Rules

Frequently Asked Questions

What does the Iga Swiatek vs. Marta Kostyuk prediction market track?

The outcomes listed above show how traders are pricing this question. Compare outcome prices from Kalshi, Polymarket, ProphetX in one place. Each price reflects the market’s implied probability, not a guaranteed result.

What are the latest Iga Swiatek vs. Marta Kostyuk odds?

The latest available prices are Marta Kostyuk: 1.0¢ on Kalshi, 0.1¢ on Polymarket, 77.4¢ on ProphetX; Iga Swiatek: 99.0¢ on Kalshi, 99.9¢ on Polymarket, 21.9¢ on ProphetX. Prices are quoted in cents per $1 share. Check the venue for executable prices and available liquidity.

Why do Iga Swiatek vs. Marta Kostyuk odds vary across prediction markets?

The largest price difference shown across venues is 78.1 percentage points. Venues have different traders, liquidity and fees, so their prices can differ. A price gap alone does not establish an executable arbitrage opportunity; compare settlement rules and the actual buy and sell prices.

How do Iga Swiatek vs. Marta Kostyuk prediction market payouts work?

For example, Marta Kostyuk at 38.7¢ implies about a 38.7% chance. For a standard $1 contract, a share pays $1 if its outcome settles as correct and $0 if it settles as incorrect. A winning share bought at 40¢ earns 60¢ before fees. Check each venue’s settlement rules, fees and eligibility before trading.

Iga Swiatek vs. Marta Kostyuk

About This Market

Iga Swiatek vs. Marta Kostyuk

About This Market

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Frequently Asked Questions

Iga Swiatek vs. Marta Kostyuk

About This Market

Iga Swiatek vs. Marta Kostyuk

About This Market

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Zane Stevens vs. Shintaro Imai

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Live Markets

Moneyline

Smart Trade Router

Resolution Oracles

Market Rulebook: Iga Swiatek vs. Marta Kostyuk

Frequently Asked Questions