SimpleFunctions
Winner-take-all · 3 outcomes3 contractsKalshirefreshed 3 min agoCloses Nov 3, 2026 · 178d

Will exactly 1 Senate Democratic members lose their primary in 2026

Leader sits at 79% across 3 bound outcomes, runner-up at 14%. This is a winner-take-all market — the headline is the leader’s price, not an arithmetic mean.

Leader probability

79%

0

runner-up 14¢leader 79¢

Outcomes

3

winner-take-all

Runner-up

14¢

1

Spread

65pp

dominant leader

24h volume

$81

thin orderbook

Closes

Nov 3, 2026

178 days

Venue

Kalshi

3 bound

30-day trend

0%50%100%-30d-3w-2w-1wtoday0: 80% (17 days, 11 points)0: 80% on 2026-05-071: 16% (17 days, 10 points)1: 16% on 2026-05-082: 5% (17 days, 3 points)2: 5% on 2026-05-06
080¢116¢25¢
Top 3 candidates by current price · 17d

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.

Analysis

This market estimates an 83% probability that exactly one Democratic senator will lose their primary election in 2026. Primary losses among incumbent senators are relatively rare, particularly within a single party in one cycle. The high probability reflects expectations of strong Democratic incumbency advantages and limited primary challenges, though it could shift if high-profile primaries develop or if incumbent senators face unexpected internal-party opposition. The outcome will be definitively settled after all Senate primaries conclude in late 2026, with most states holding primaries between August and September.

  • Number of vulnerable Democratic incumbents facing organized primary opposition as of spring 2026
  • Fundraising and polling performance of Democratic senators relative to potential challengers in their respective states
  • Turnout levels in Democratic primaries, which could amplify or diminish the impact of anti-incumbent sentiment
  • Timing and intensity of internal party dynamics, particularly around policy disagreements or controversial votes
  • Completion of all Senate Democratic primaries by November 2026, which will directly determine the outcome

What moved the line

  • May 816pp1016¢ · Kalshi
  • May 214pp128¢ · Kalshi
  • May 604pp8480¢ · Kalshi

Recently closed in election 2026

These markets stopped trading. Last odds and any captured outcome are shown above — full settlement detail lives at the venue.

More like this

Other questions in election 2026.

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: 3 min ago.