The Prediction Markets

Market comparison

Boulter vs Ishii

2 venues · 17 outcome rows · 1 comparable lines · event identity linked · 0 verified parity · active

Polymarket

Open venue ↗

16 outcomes · $1K reported volume

Observed 3m ago

Recorded venue end date: Oct 31, 2026

Kalshi

Open venue ↗

2 outcomes · $1K reported volume

Observed 26s ago

Recorded venue end date: Nov 7, 2026

Check settlement rules before comparing contracts. Matched outcomes may settle differently. These venues also report end dates more than 48 hours apart; event identity does not mean the contracts close or settle together. These are stored prices; record update times do not certify live quotes. Differences exclude fees and available size.

Known rule differences between venues

  • Postponement: Kalshi resolves to a fair price if the game does not start within 48 hours of the scheduled time (tennis: not finished within two weeks); Polymarket stays open until the game is played and resolves 50-50 only if it is cancelled with no make-up (UFC/tennis: ~14 days).
  • Ties and draws in two-way sports (NFL, college football, UFC no-contest): both venues pay 50/50.
  • Soccer: both settle on 90 minutes plus stoppage time; extra time and penalties excluded.
  • Tennis: Kalshi requires a ball to be played and pays the winner; Polymarket pays the player who advances, including on retirement. A pre-match walkover is a fair price on Kalshi, 50-50 on Polymarket.
  • UFC: Kalshi ignores result changes after expiry; Polymarket follows the official UFC result.
  • Polymarket two-way moneylines are one contract priced on the first-named side; the other side is its complement (recorded as a derived relation, not a link).

A shared identity alone does not make a price difference executable.

Boulter

Partial parity

Payoffs match in ordinary outcomes; see the rule differences above.

Polymarket

50.5%

Bid 50.0% · Ask 51.0%

Pan Pacific Open, Qualification: Katie Boulter vs Sayaka Ishii

Open Polymarket ↗

Kalshi

55.0%

Bid 50.0% · Ask 55.0%

Katie Boulter

Open Kalshi ↗

Price difference 4.5 pp

Completed Match

Not aligned

No persisted outcome identity connects these venue contracts.

Polymarket

33.5%

Bid 1.0% · Ask 66.0%

Completed Match

Open Polymarket ↗

Kalshi

—

Pan Pacific Open, Qualification: Katie Boulter vs Sayaka Ishii Set 1 Winner

Not aligned

No persisted outcome identity connects these venue contracts.

Polymarket

62.5%

Bid 46.0% · Ask 79.0%

Set Handicap: Sayaka Ishii (-1.5) vs Katie Boulter (+1.5)

Open Polymarket ↗

Kalshi

—

Pan Pacific Open, Qualification: Katie Boulter vs Sayaka Ishii Set 1 Winner

Not aligned

No persisted outcome identity connects these venue contracts.

Polymarket

50.5%

Bid 48.0% · Ask 53.0%

Pan Pacific Open, Qualification: Katie Boulter vs Sayaka Ishii Set 1 Winner

Open Polymarket ↗

Kalshi

—

Pan Pacific Open, Qualification: Katie Boulter vs Sayaka Ishii Set 1 Winner

Not aligned

No persisted outcome identity connects these venue contracts.

Polymarket

50.0%

Bid — · Ask 100.0%

Pan Pacific Open, Qualification: Katie Boulter vs Sayaka Ishii Set 2 Winner

Open Polymarket ↗

Kalshi

—

Pan Pacific Open, Qualification: Katie Boulter vs Sayaka Ishii Set 1 Winner

Not aligned

No persisted outcome identity connects these venue contracts.

Polymarket

50.0%

Bid 3.0% · Ask 97.0%

Pan Pacific Open, Qualification: Katie Boulter vs Sayaka Ishii Total Sets: O/U 2.5

Open Polymarket ↗

Kalshi

—

Pan Pacific Open, Qualification: Katie Boulter vs Sayaka Ishii Set 1 Winner

Not aligned

No persisted outcome identity connects these venue contracts.

Polymarket

49.5%

Bid 2.0% · Ask 97.0%

Set Handicap: Katie Boulter (-1.5) vs Sayaka Ishii (+1.5)

Open Polymarket ↗

Kalshi

—

Pan Pacific Open, Qualification: Katie Boulter vs Sayaka Ishii Set 1 Winner

Not aligned

No persisted outcome identity connects these venue contracts.

Polymarket

49.0%

Bid 1.0% · Ask 97.0%

Pan Pacific Open, Qualification: Katie Boulter vs Sayaka Ishii Match O/U 22.5

Open Polymarket ↗

Kalshi

—

Pan Pacific Open, Qualification: Katie Boulter vs Sayaka Ishii Set 1 Winner

Not aligned

No persisted outcome identity connects these venue contracts.

Polymarket

49.0%

Bid 1.0% · Ask 97.0%

Pan Pacific Open, Qualification: Katie Boulter vs Sayaka Ishii Match O/U 21.5

Open Polymarket ↗

Kalshi

—

Pan Pacific Open, Qualification: Katie Boulter vs Sayaka Ishii Set 1 Winner

Not aligned

No persisted outcome identity connects these venue contracts.

Polymarket

49.0%

Bid 1.0% · Ask 97.0%

Pan Pacific Open, Qualification: Katie Boulter vs Sayaka Ishii Match O/U 23.5

Open Polymarket ↗

Kalshi

—

Pan Pacific Open, Qualification: Katie Boulter vs Sayaka Ishii Set 1 Winner

Not aligned

No persisted outcome identity connects these venue contracts.

Polymarket

48.5%

Bid — · Ask 97.0%

Pan Pacific Open, Qualification: Katie Boulter vs Sayaka Ishii Set 1 O/U 9.5

Open Polymarket ↗

Kalshi

—

Pan Pacific Open, Qualification: Katie Boulter vs Sayaka Ishii Set 1 Winner

Not aligned

No persisted outcome identity connects these venue contracts.

Polymarket

48.5%

Bid — · Ask 97.0%

Pan Pacific Open, Qualification: Katie Boulter vs Sayaka Ishii Set 1 O/U 10.5

Open Polymarket ↗

Kalshi

—

Pan Pacific Open, Qualification: Katie Boulter vs Sayaka Ishii Set 1 Winner

Not aligned

No persisted outcome identity connects these venue contracts.

Polymarket

48.5%

Bid — · Ask 97.0%

Pan Pacific Open, Qualification: Katie Boulter vs Sayaka Ishii Set 1 O/U 8.5

Open Polymarket ↗

Kalshi

—

Pan Pacific Open, Qualification: Katie Boulter vs Sayaka Ishii Set 1 Winner

Not aligned

No persisted outcome identity connects these venue contracts.

Polymarket

48.0%

Bid — · Ask 96.0%

Pan Pacific Open, Qualification: Katie Boulter vs Sayaka Ishii Set 2 O/U 9.5

Open Polymarket ↗

Kalshi

—

Pan Pacific Open, Qualification: Katie Boulter vs Sayaka Ishii Set 1 Winner

Not aligned

No persisted outcome identity connects these venue contracts.

Polymarket

48.0%

Bid — · Ask 96.0%

Pan Pacific Open, Qualification: Katie Boulter vs Sayaka Ishii Set 2 O/U 8.5

Open Polymarket ↗

Kalshi

—

Pan Pacific Open, Qualification: Katie Boulter vs Sayaka Ishii Set 1 Winner

Not aligned

No persisted outcome identity connects these venue contracts.

Polymarket

48.0%

Bid — · Ask 96.0%

Pan Pacific Open, Qualification: Katie Boulter vs Sayaka Ishii Set 2 O/U 10.5

Open Polymarket ↗

Kalshi

—

Sayaka Ishii

Not aligned

No persisted outcome identity connects these venue contracts.

Polymarket

—

Kalshi

42.0%

Bid 42.0% · Ask 48.0%

Sayaka Ishii

Open Kalshi ↗

Prices are shown as percentages of a $1 payout. “pp” means percentage points. A dash means data is unavailable.

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