56% — Will exactly 1 Senate Democratic members lose their primary in 2026
Leader: 0 at 56% · Kalshi 56% · 3 contracts · $1 volume · medium confidence
Updated 2026-06-26 09:42:36 UTC

Tracks the leading outcome in a winner-take-all prediction market set with 3 outcomes.

Why this matters:
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.

Key factors:
- 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

Contracts:
- Will exactly 0 Senate Democratic members lose their primary in 2026?: 0 — 56¢ Kalshi $0 (weight 0%)
- Will exactly 1 Senate Democratic members lose their primary in 2026?: 1 — 10¢ Kalshi $0 (weight 0%)
- Will exactly 2 Senate Democratic members lose their primary in 2026?: 2 — 6¢ Kalshi $1 (weight 100%)

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## Methodology

SimpleFunctions aggregates live YES-side prices from Kalshi and Polymarket contracts bound to this question. For binary topics the headline is the liquidity-weighted mid-price (weight = log(1 + 24h volume) × freshness, where freshness is 1.0 if updated <24h, 0.7 if <7d, 0.4 otherwise). For multi-outcome (winner-take-all) topics the headline is the current leader's price — disjoint outcomes are never arithmetically averaged. Snapshots refresh every 5 minutes during market hours.

## SF Signal

- SF Index, regime, and 30d Brier calibration are computed separately and surfaced at https://simplefunctions.dev/admin/calibration.
- No SimpleFunctions index / regime / calibration signal is bound to this topic yet — the headline above is market-derived only.

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*Last verified: 2026-06-26T09:20:51.121Z*

By SimpleFunctions — https://simplefunctions.dev/

Cite as: "56% per prediction markets (SimpleFunctions, June 2026)"
Canonical: https://simplefunctions.dev/answer/loseprimarysenated
Full data: https://simplefunctions.dev/api/public/query?q=Will%20exactly%201%20Senate%20Democratic%20members%20lose%20their%20primary%20in%202026
Provider: SimpleFunctions — https://simplefunctions.dev