TOTAL VOLUME:
$154.5b
24H VOL:
$271,200,656
24H TRANSACTIONS:
2,984,640,614
OPEN INTEREST:
$1,922,627,141
420,368
Markets across
40,352
events
MATCHED EVENTS:
4,484
PLATFORM COVERAGE:
5
Polymarket:
37%
VS.
Kalshi:
63%
Closed: Oct 9, 10:38 AM EST
Polymarket
Description
This group forecasts the Labour Party's vote share in the 2026 Holborn and St Pancras by-election, triggered by Keir Starmer's resignation. Markets exist across platforms with varying approaches to defining success, ranging from specific percentage thresholds to questions about winning less than 30% of the vote.
PredictionHero - Resolution Divergence Alerts (RDA)
Divergence Detected
Issue: Kalshi offers multiple markets with different thresholds, while Polymarket asks specific range-based questions. This creates SKU risk as traders need to understand the precise question being asked on each platform.Hero tip: Carefully consider the specific question being asked on each platform. Kalshi's markets are range-based (e.g., >30%), while Polymarket's are interval-based (e.g., 30-35%).Critical divergence points:
- Polymarket: Polymarket presents markets asking if Labour will win a specific percentage range of the vote (e.g., 30-35%). Resolution depends on whether the actual vote share falls within that range. "If the reported value falls exactly between two brackets, then this market will resolve to the higher range bracket."
- Kalshi: Kalshi offers multiple markets, each resolving YES if the Labour vote share is within a specified range (e.g., 40%-100%). Resolution is straightforward based on whether the vote share meets the threshold. "If the certified percentage of the popular vote received by Labour Party in the 2026 Holborn and St Pancras by-election is 40% to 100%, inclusive of both endpoints, then the market resolves to Yes."
Polymarket
A by-election for the United Kingdom parliamentary constituency of Holborn and St Pancras is scheduled to be held on October 8, 2026, following the resignation of incumbent Sir Keir Starmer. This market will resolve according to the percentage of valid votes received by the Labour Party candidate in the Holborn and St Pancras by-election. The percentage will be measured as the number of valid votes received by the Labour Party candidate divided by the total number of valid votes cast in the by-election. Valid vote percentages will be counted only where the official results attribute them to the candidate standing for the Labour Party. Votes attributed to other candidates or party designations will not count, regardless of endorsements or electoral cooperation. If the reported value falls exactly between two brackets, then this market will resolve to the higher range bracket. If the results of this by-election are not definitively known by June 30, 2027, 11:59 PM ET, this market will resolve to the lowest range bracket. This market will resolve based on the results of this by-election as indicated by a consensus of credible reporting. If there is ambiguity, this market will resolve based solely on the official results as published by Camden Council (https://www.camden.gov.uk/).
Kalshi
The event determines whether the Labour Party achieves specified vote percentage thresholds in the 2026 Holborn and St Pancras by-election. Each market resolves to 'Yes' if the certified percentage of votes received by Labour falls within the inclusive range defined for that market (from 20% to 65%). The vote percentage is calculated as the number of votes for Labour divided by the total valid votes cast, multiplied by 100 and rounded. Certified or official results are used, with unofficial results permitted only under specific conditions. Write-in votes are included in the calculation, while invalid, spoiled, or rejected ballots are excluded. If multiple rounds of voting occur, the specified round or the first round is used unless otherwise stated. Should the election be cancelled, suspended, or postponed before conclusion, or if no certified results are available by the expiration date, the market resolves 'NO,' unless modified by the Fully-Conducted Elections provision. Any recount altering the certified percentage before expiration will use the most recent certified figure.
Frequently asked questions
Prediction market odds often provide a different perspective than traditional polling averages. While polls capture a snapshot of current voter intentions, this market reflects what traders believe will *actually* happen, incorporating a wider range of information and anticipating potential shifts in sentiment. Discrepancies can arise due to factors like differing methodologies, weighting, and the ability of market participants to trade on inside information or nuanced understandings of the electorate. This market can be a valuable complement to polling data, offering a forward-looking assessment of the by-election.