# How many Democratic House Incumbents will not win their Primary — >15

> 7-9 leads at 43%, runner-up 40% across 6 winner-take-all outcomes — refreshed 6 min ago.

URL: https://simplefunctions.dev/odds/how-many-democratic-house-incumbents-not-win-their-primary
Updated: 2026-05-09T05:05:41.884Z
Category: general · Topic: election-2026
Status: active
Closes: 2026-08-31

## Headline

- Leader: 7-9 at 43%
- Runner-up: 4-6 at 40%
- Outcomes: 6 (winner-take-all)
- Venue: Polymarket (6 contracts)
- 24h volume: $13

## Bound contracts (6)

| Outcome | Price | 24h | Volume | Venue | Slug |
|---|---|---|---|---|---|
| 7-9 | 43¢ | +4pp | $5 | polymarket | /markets/how-many-democratic-house-incumbents-will-not-win-polymarket-0x92d9b1b2184185bcd2f636f8b1c00d2e8900037541c5530b31cd241a2eab239b |
| 4-6 | 40¢ | −1pp | $0 | polymarket | /markets/how-many-democratic-house-incumbents-will-not-win-polymarket-0xd8eabfa8f66981b8d3a6eb675bb8af14c5f6efe031b4a5c32df905759f223879 |
| <3 | 28¢ | −1pp | $0 | polymarket | /markets/how-many-democratic-house-incumbents-will-not-win-polymarket-0x26d14a0493969677b36b61f22d36675350c18794efe409a1b596a70ab8dde460 |
| >15 | 4¢ | ±0 | $0 | polymarket | /markets/how-many-democratic-house-incumbents-will-not-win-polymarket-0xa30d0d62ddebe5a59d1567e5a95445b8e1dda8c9884f4342b4680000205d5f58 |
| 13-15 | 4¢ | −35pp | $0 | polymarket | /markets/how-many-democratic-house-incumbents-will-not-win-polymarket-0x47fd8303835d9108252343069ada769162976137e4e1c22b94b1cb305cd35d8a |
| 10-12 | 3¢ | ±0 | $8 | polymarket | /markets/how-many-democratic-house-incumbents-will-not-win-polymarket-0x3b32ef6897c33e7cac03641f3b16f25de3bbba86c48193ae7250b81bd5dc8e36 |

## 30-day trajectory

| Day | 7-9 | 4-6 | <3 |
|---|---|---|---|
| 2026-04-09 | — | — | 24 |
| 2026-04-10 | — | 71 | — |
| 2026-04-21 | 25 | 65 | 13 |
| 2026-04-25 | 26 | 60 | 15 |
| 2026-05-02 | 41 | 42 | 49 |
| 2026-05-09 | 45 | 38 | 29 |

_26 days of price history captured. Each row is the daily mean of intraday 5-min captures._

## What moved the line

- 2026-05-07 · 13-15 −35pp 38→3¢ · polymarket
- 2026-05-06 · <3 −20pp 49→29¢ · polymarket
- 2026-05-03 · 4-6 −6pp 42→36¢ · polymarket
- 2026-05-09 · 7-9 +4pp 41→45¢ · polymarket
- 2026-05-06 · 4-6 +4pp 36→40¢ · polymarket

## Analysis

This probability estimates the likelihood that more than 15 Democratic House incumbents will lose their primary elections in 2026. At 24%, the market suggests this is a relatively unlikely outcome, though not negligible. Primary defeat rates for incumbents are historically low—typically under 5% nationally—so exceeding 15 losses would represent a significant departure from the norm. The current pricing reflects several competing dynamics: potential vulnerability from redistricting effects, primary challenges from progressive candidates in certain districts, and retirements that reduce the total pool of incumbents running. The market appears to weight historical incumbent resilience heavily against speculation about heightened primary activity. The outcome will become clearer as primary election dates approach in summer 2026 and filing deadlines pass, with the cumulative results fully resolved by November 2026.

### Key factors

- Historical primary defeat rates for House incumbents average 1-3%, making >15 losses a statistical outlier that would require unprecedented primary activity
- The total number of Democratic House incumbents running in 2026 remains uncertain; if fewer than 250-280 run, the >15 threshold becomes proportionally harder to reach
- Primary challenge intensity varies significantly by region and district competitiveness, with progressive primary challenges concentrated in specific districts rather than broadly distributed
- Retirement decisions by incumbents directly affect the denominator and resolved count—ongoing retirements through summer 2026 will clarify the realistic threshold
- Competitive primary outcomes depend on candidate quality, fundraising, and local political dynamics in specific districts, which remain fluid rather than predetermined

## Methodology

Headline is the **leader's price**, not an arithmetic mean — averaging disjoint winner-take-all outcomes is meaningless. Per-outcome prices come from the venue's last-traded mid; cross-venue values are simple means across contracts on each venue.

## How to use this data

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- Topic hub: https://simplefunctions.dev/predictions/election-2026

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