How many Democratic Senate Incumbents will not win their Primary? : 0
Leader sits at 76% across 6 bound outcomes, runner-up at 43%. This is a winner-take-all market — the headline is the leader’s price, not an arithmetic mean.
Leader probability
0
Outcomes
6
winner-take-all
Runner-up
43¢
3
Spread
33pp
contested
24h volume
$8
thin orderbook
Closes
—
not derived
Venue
Polymarket
6 bound
30-day trend
Bracket family
How the bracket ladder is priced.
Each row is one outcome on the venue. Sorted by 24h volume — the heaviest book is at the top.
Cluster 1
How many Democratic Senate Incumbents will not win their Primary
How many Democratic Senate Incumbents will not win their Primary? : 4
0x71aeaa…57d6
How many Democratic Senate Incumbents will not win their Primary? : >4
0xaafd8a…23f0
How many Democratic Senate Incumbents will not win their Primary? : 3
0x646a41…6609
How many Democratic Senate Incumbents will not win their Primary? : 2
0x694830…f129
How many Democratic Senate Incumbents will not win their Primary? : 1
0x8bc2cc…b7f9
How many Democratic Senate Incumbents will not win their Primary? : 0
0x21ac6c…fa4a
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.
- ›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
What moved the line
- May 63↑15pp3→18¢ · Polymarket
- May 83↓11pp20→9¢ · Polymarket
- May 61↓8pp20→12¢ · Polymarket
- May 71↑8pp12→20¢ · Polymarket
- May 6>4↓8pp17→9¢ · Polymarket
Recently closed in election 2026
- Will a reconciliation bill passed the Senate before May 20, 2026last 94% · 1d
- Will John Fetterman leave the Democratic party before Jun 1, 2026last 16% · 1d
- Will the Democratic National Committee release a comprehensive post-election report of the 2024 election before Aug 1, 2026last 67% · 1d
- Balance of Power: 2026 Midterms: D Senate, R Houselast 3% · 1d
- What will any participating candidate say during California Governor Debatenolast 55% · 1d
These markets stopped trading. Last odds and any captured outcome are shown above — full settlement detail lives at the venue.
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How we compute these odds
SimpleFunctions aggregates live prediction-market contracts from Kalshi and Polymarket. Each slug groups contracts that resolve on the same underlying event, identified by venue event_id.
For binary slugs, the headline probability is the liquidity-weighted mid-price across all bound contracts. For multi-outcome slugs (e.g. elections with 3+ candidates), the headline is the leader’s price; we never arithmetically average disjoint outcomes — that would produce a number with no real-world meaning.
Snapshots refresh every 5 minutes during market hours; daily aggregates are computed at 04:00 UTC. The 30-day sparkline is drawn from per-ticker daily means stored in market_indicator_daily; 24h delta and movement events are derived from the same source.
Last updated on this page: 6 min ago.