# Will Green Party receive at least 5% of the popular vote in the 2026 Holborn and St Pancras by-election

> Liquidity-weighted aggregate at 42% across 20 contracts — refreshed 49 min ago.

URL: https://simplefunctions.dev/odds/holbornvote
Updated: 2026-09-07T11:21:05.470Z
Category: politics · Topic: election-2026
Status: active
Closes: 2027-12-31

## Headline

- Probability: 42% (liquidity-weighted across 20 contracts)
- Venue: Kalshi (20 contracts)
- 24h volume: $0

## Bound contracts (20)

| Outcome | Price | 24h | Volume | Venue | Slug |
|---|---|---|---|---|---|
| At least 10% | 90¢ | −1pp | $0 | kalshi | /markets/will-green-party-receive-at-least-10-of-the-popula-kalshi-kxholbornvote-26dec31grn-10 |
| At least 15% | 88¢ | ±0 | $0 | kalshi | /markets/will-green-party-receive-at-least-15-of-the-popula-kalshi-kxholbornvote-26dec31grn-15 |
| At least 20% | 74¢ | −3pp | $0 | kalshi | /markets/will-green-party-receive-at-least-20-of-the-popula-kalshi-kxholbornvote-26dec31grn-20 |
| At least 25% | 63¢ | +3pp | $0 | kalshi | /markets/will-green-party-receive-at-least-25-of-the-popula-kalshi-kxholbornvote-26dec31grn-25 |
| At least 30% | 40¢ | −2pp | $0 | kalshi | /markets/will-green-party-receive-at-least-30-of-the-popula-kalshi-kxholbornvote-26dec31grn-30 |
| At least 35% | 27¢ | −1pp | $0 | kalshi | /markets/will-green-party-receive-at-least-35-of-the-popula-kalshi-kxholbornvote-26dec31grn-35 |
| At least 40% | 13¢ | −4pp | $0 | kalshi | /markets/will-green-party-receive-at-least-40-of-the-popula-kalshi-kxholbornvote-26dec31grn-40 |
| At least 5% | 94¢ | −2pp | $0 | kalshi | /markets/will-green-party-receive-at-least-5-of-the-popular-kalshi-kxholbornvote-26dec31grn-5 |
| At least 20% | 93¢ | ±0 | $0 | kalshi | /markets/will-labour-party-receive-at-least-20-of-the-popul-kalshi-kxholbornvote-26dec31lab-20 |
| At least 30% | 87¢ | — | $0 | kalshi | /markets/will-labour-party-receive-at-least-30-of-the-popul-kalshi-kxholbornvote-26dec31lab-30 |
| At least 35% | 67¢ | — | $0 | kalshi | /markets/will-labour-party-receive-at-least-35-of-the-popul-kalshi-kxholbornvote-26dec31lab-35 |
| At least 40% | 40¢ | ±0 | $0 | kalshi | /markets/will-labour-party-receive-at-least-40-of-the-popul-kalshi-kxholbornvote-26dec31lab-40 |
| At least 45% | 22¢ | ±0 | $0 | kalshi | /markets/will-labour-party-receive-at-least-45-of-the-popul-kalshi-kxholbornvote-26dec31lab-45 |
| At least 50% | 10¢ | ±0 | $0 | kalshi | /markets/will-labour-party-receive-at-least-50-of-the-popul-kalshi-kxholbornvote-26dec31lab-50 |
| At least 55% | 5¢ | +1pp | $0 | kalshi | /markets/will-labour-party-receive-at-least-55-of-the-popul-kalshi-kxholbornvote-26dec31lab-55 |
| At least 65% | 3¢ | +1pp | $0 | kalshi | /markets/will-labour-party-receive-at-least-65-of-the-popul-kalshi-kxholbornvote-26dec31lab-65 |
| At least 12% | 14¢ | −6pp | $0 | kalshi | /markets/will-reform-uk-receive-at-least-12-of-the-popular-kalshi-kxholbornvote-26dec31ruk-12 |
| At least 15% | 6¢ | −5pp | $0 | kalshi | /markets/will-reform-uk-receive-at-least-15-of-the-popular-kalshi-kxholbornvote-26dec31ruk-15 |
| At least 20% | 4¢ | −1pp | $0 | kalshi | /markets/will-reform-uk-receive-at-least-20-of-the-popular-kalshi-kxholbornvote-26dec31ruk-20 |
| At least 25% | 3¢ | +1pp | $0 | kalshi | /markets/will-reform-uk-receive-at-least-25-of-the-popular-kalshi-kxholbornvote-26dec31ruk-25 |

## 30-day trajectory

| Day | Aggregate |
|---|---|
| 2026-09-02 | 33 |
| 2026-09-03 | 36 |
| 2026-09-04 | 29 |
| 2026-09-05 | 36 |
| 2026-09-06 | 49 |

_5 days of price history captured. Each row is the daily mean of intraday 5-min captures._

## What moved the line

- 2026-09-03 · At least 15% +25pp 38→63¢ · kalshi
- 2026-09-03 · At least 20% +25pp 19→44¢ · kalshi
- 2026-09-04 · At least 20% +24pp 44→68¢ · kalshi
- 2026-09-04 · At least 25% +20pp 29→49¢ · kalshi
- 2026-09-04 · At least 30% +16pp 15→31¢ · kalshi

## Analysis

This probability reflects traders' assessment that the Green Party will secure at least 5% of the vote share in the Holborn and St Pancras by-election. The 40% odds suggest meaningful uncertainty about Green performance, likely driven by the party's historical vote share in this particular constituency and broader national polling trends. The contract ladder shows traders assign substantially lower probability to higher thresholds—the 10% barrier sits at 72¢ while 25% drops to just 15¢—indicating a consensus view that Green will most likely finish between 5-10%. The upcoming by-election result will definitively resolve this, with the winner and vote totals determined on polling day. Current trading volume is low, suggesting limited market confidence in price discovery.

### Key factors

- Green Party's performance in the 2024 general election in Holborn and St Pancras relative to the 5% threshold
- Current national polling for the Green Party and their trajectory in recent months
- Candidate quality and campaign intensity specific to this by-election compared to typical contests
- Local demographic and political composition of the Holborn and St Pancras constituency
- Turnout patterns in recent by-elections and whether they typically favor or disadvantage minor parties like the Greens

## Methodology

Probability is **liquidity-weighted** across all bound Kalshi/Polymarket contracts: Σ(price × volume) ÷ Σ(volume). 30-day trajectory uses the daily mean of intraday 5-min captures. 24h delta = today's mean − yesterday's mean. Movement events are ≥3pp daily moves in the last 7 days.

## How to use this data

- HTML: https://simplefunctions.dev/odds/holbornvote
- JSON: https://simplefunctions.dev/api/public/odds?slug=holbornvote
- Topic hub: https://simplefunctions.dev/predictions/election-2026

## License

CC-BY-4.0. Attribute "SimpleFunctions" with a link to https://simplefunctions.dev. See https://simplefunctions.dev/legal for terms.