The Prediction Markets

When will the next UK parliamentary by-election be called?

Closes
Jan 1, 2028, in 15 months
Traded
$10K
Venues
Kalshi
Prices updated
3 min ago
Share

What the markets expect

Before Jul 1, 2027 82%

Next is Before Jan 1, 2028 at 52%. Only Kalshi lists this market, so there is no second price to compare.

Odds by venue

Consensus blends each venue’s last price, weighted by how much has traded there. Best Yes price is the cheapest ask across venues, and the payout is what a winning $100 stake returns before fees. Open a row for each venue’s contract name, bid and ask, and how closely their rules match.

Prices come from our regular polls of each venue, the oldest 3 min ago. Ages are as of when this page was built.

  • Kalshi
Before Jul 1, 2027
82%
Kalshi 82%polled, 3 min agoBest Yes 86¢ on Kalshi, $100 pays $116 (1.16x)
Kalshi
Contract
Before Jul 1, 2027
Last price
82%
As of
Polled 3 min ago
Buy Yes
86¢
Sell Yes
66¢
$100 on Yes pays
$116 (1.16x)
Volume
$5K
Trade this on Kalshi
Before Jan 1, 2028
52%
Kalshi 52%polled, 3 min agoBest Yes 99¢ on Kalshi, $100 pays $101 (1.01x)
Kalshi
Contract
Before Jan 1, 2028
Last price
52%
As of
Polled 3 min ago
Buy Yes
99¢
Sell Yes
5¢
$100 on Yes pays
$101 (1.01x)
Trade this on Kalshi
Before Apr 1, 2027
48%
Kalshi 48%polled, 3 min agoBest Yes 50¢ on Kalshi, $100 pays $200 (2.00x)
Kalshi
Contract
Before Apr 1, 2027
Last price
48%
As of
Polled 3 min ago
Buy Yes
50¢
Sell Yes
3¢
$100 on Yes pays
$200 (2.00x)
Volume
$5K
Trade this on Kalshi
Before Jan 1, 2027
35%
Kalshi 35%polled, 3 min agoBest Yes 36¢ on Kalshi, $100 pays $278 (2.78x)
Kalshi
Contract
Before Jan 1, 2027
Last price
35%
As of
Polled 3 min ago
Buy Yes
36¢
Sell Yes
3¢
$100 on Yes pays
$278 (2.78x)
Volume
$5
Trade this on Kalshi
Before Nov 1, 2026
11%
Kalshi 11%polled, 3 min agoBest Yes 13¢ on Kalshi, $100 pays $769 (7.69x)
Kalshi
Contract
Before Nov 1, 2026
Last price
11%
As of
Polled 3 min ago
Buy Yes
13¢
Sell Yes
2¢
$100 on Yes pays
$769 (7.69x)
Volume
$12
Trade this on Kalshi

Who resolves this market

Kalshi
Kalshi resolves via:
Kalshi (CFTC-regulated exchange), source: Clerk of the Crown in Chancery, Clerk of the Crown for Northern Ireland

How the odds have moved

The top 3 outcomes on both venues, with the consensus between them. Hover for exact values.

  • Before Jul 1, 2027
  • Before Jan 1, 2028
  • Before Apr 1, 2027

Order books

Each venue’s resting orders for the selected outcome’s Yes contract, side by side. Top of book streams live; depth refreshes every 15 seconds.

Kalshi

Open on Kalshi ↗

Top of book

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Best bid
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Spread
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Best ask
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Depth · top 8 levels

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Recent trades

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What your stake buys

Enter a stake to see where it buys the most after fees, using each venue’s live order book.

$
Buy

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Buys at the asks resting now (taker orders), cheapest after fees first, from order-book snapshots up to 15 seconds old. Fees: Kalshi 0.07 × price × (1 − price) per share, rounded up to the cent; Polymarket 0.04 × price × (1 − price) per share (politics rate). Fee calculator. Estimates only, not advice.

About this market

Live prediction market odds for "When will the next UK parliamentary by-election be called?". Before Jul 1, 2027 leads at 82%. Next is Before Jan 1, 2028 at 52%. $10K has traded across 5 outcomes on Kalshi. The market is expected to resolve by Jan 1, 2028.

Questions

What does the consensus price mean?

It is the price of a Yes contract that pays $1 if the outcome happens. A 14¢ price means traders put the chance near 14%. Where two venues list the same outcome, we blend their last prices, weighting the venue with more trading volume more heavily (neither counts for less than a quarter). When only one outcome can win, each venue’s prices add up to a little over 100% (its margin); the fair chance removes that margin so the outcomes add up to exactly 100%.

How is the payout worked out?

A Yes contract pays $1 if it wins, so at the best ask a $100 stake buys 100 ÷ ask contracts. At 18¢ that is about 555 contracts, paying $556 (5.56x) if Yes happens. Venue fees and price slippage on larger orders are not included.

Why do the venues show different prices?

Each venue has its own traders, fees and order book. Contracts can also settle on slightly different terms, which is why each row lists how closely the rules match.

Is a price gap an arbitrage?

Only when you can buy Yes on one venue below what someone pays for Yes on the other, after fees, and both contracts settle the same way. We show the executable bid and ask so you can check.

How fresh are these prices?

Venue prices refresh every few minutes, and the order book and live quotes stream continuously. Each venue’s card shows when we last observed it.

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