# How many Democratic Senate Incumbents will not win their Primary? : 0

> 0 leads at 76%, runner-up 16% across 6 winner-take-all outcomes — refreshed 1 min ago.

URL: https://simplefunctions.dev/odds/how-many-democratic-senate-incumbents-not-win-their-primary
Updated: 2026-05-09T04:20:41.171Z
Category: general · Topic: election-2026
Status: active

## Headline

- Leader: 0 at 76%
- Runner-up: 3 at 16%
- Outcomes: 6 (winner-take-all)
- Venue: Polymarket (6 contracts)
- 24h volume: $8

## Bound contracts (6)

| Outcome | Price | 24h | Volume | Venue | Slug |
|---|---|---|---|---|---|
| 0 | 76¢ | −4pp | $0 | polymarket | /markets/how-many-democratic-senate-incumbents-will-not-win-polymarket-0x21ac6c0f306c50f07c5ab8486b36b67320598e69350fda84b6dad1c69805fa4a |
| 3 | 16¢ | −11pp | $0 | polymarket | /markets/how-many-democratic-senate-incumbents-will-not-win-polymarket-0x646a41d4d0d87eb241ec4f3cbd6d04c0d6635152f120be5d7f506cee17186609 |
| 2 | 12¢ | −3pp | $0 | polymarket | /markets/how-many-democratic-senate-incumbents-will-not-win-polymarket-0x694830be50496910a77449d1f1b7bb9b9096649284cff696caab7c4171ecf129 |
| 1 | 11¢ | −5pp | $0 | polymarket | /markets/how-many-democratic-senate-incumbents-will-not-win-polymarket-0x8bc2cc2e5ae5b2be9a2d9af2d7f0253195a7295ca851b01c9e2ae3f3edb1b7f9 |
| >4 | 9¢ | −3pp | $0 | polymarket | /markets/how-many-democratic-senate-incumbents-will-not-win-polymarket-0xaafd8a84a1ec1e5fe305606ad753fe69e15b78fa1eb34cc4d2d8b2c53a2f23f0 |
| 4 | 3¢ | ±0 | $8 | polymarket | /markets/how-many-democratic-senate-incumbents-will-not-win-polymarket-0x71aeaa0cfad6d0e5aaaf395fd9e1e6f6b4cb0a13ab3e8fe5adc0642114b857d6 |

## 30-day trajectory

| Day | 0 | 3 | 2 |
|---|---|---|---|
| 2026-04-09 | 78 | — | 10 |
| 2026-04-11 | 78 | 5 | 7 |
| 2026-04-25 | 86 | 3 | 2 |
| 2026-05-02 | 78 | 3 | 3 |
| 2026-05-08 | 74 | 9 | 10 |

_27 days of price history captured. Each row is the daily mean of intraday 5-min captures._

## What moved the line

- 2026-05-06 · 3 +15pp 3→18¢ · polymarket
- 2026-05-08 · 3 −11pp 20→9¢ · polymarket
- 2026-05-06 · 1 −8pp 20→12¢ · polymarket
- 2026-05-07 · 1 +8pp 12→20¢ · polymarket
- 2026-05-06 · >4 −8pp 17→9¢ · polymarket

## Analysis

This contract estimates a 25% probability that no Democratic Senate incumbents will lose their primary races in 2026. Primary challenges to sitting senators are relatively uncommon, but the probability reflects meaningful uncertainty about whether any current Democratic senators will face successful primary opposition this cycle. The main factors influencing this level are the overall strength of the Democratic caucus, any controversial policy positions that might invite primary challenges, and the fundraising capacity of potential challengers. The key dates that will resolve this uncertainty are the individual state primary elections throughout 2026, with major contests occurring in spring and summer months. Early filing deadlines and candidate announcement periods in each state are already underway and will clarify which incumbents face real primary threats.

### Key factors

- No Democratic Senate incumbent has failed to win renomination since 2010, suggesting structural advantages for sitting senators in their parties
- The Democratic caucus currently includes members with voting records that could invite progressive or moderate challenges in specific states, though the likelihood remains low
- Primary challenge success historically correlates with incumbent unpopularity ratings, fundraising disadvantages, or retirement decisions rather than announced candidacies
- State-by-state filing deadlines in 2026 range from winter 2025 through spring 2026, providing real-time data on actual challenge threats versus speculation
- Comparison data shows Republican Senate incumbents face similar primary dynamics in 2026, with market pricing these scenarios at measurably different probabilities

## 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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