# Will the Democratic Party hold less than 45 seats in the 120th Congress

> Above 52 leads at 20%, runner-up 16% across 19 winner-take-all outcomes — refreshed 24 min ago.

URL: https://simplefunctions.dev/odds/dsenateseats
Updated: 2026-06-08T08:20:08.176Z
Category: politics · Topic: election-2026
Status: active
Closes: 2029-02-01

## Headline

- Leader: Above 52 at 20%
- Runner-up: 50 at 16%
- Outcomes: 19 (winner-take-all)
- Venue: Kalshi (19 contracts)
- 24h volume: $17K

## Bound contracts (19)

| Outcome | Price | 24h | Volume | Venue | Slug |
|---|---|---|---|---|---|
| Above 52 | 20¢ | +1pp | $2K | kalshi | /markets/will-the-democratic-party-hold-more-than-52-seats-kalshi-kxdsenateseats-27-above52 |
| 50 | 16¢ | +1pp | $17 | kalshi | /markets/will-the-democratic-party-hold-50-seats-in-the-120-kalshi-kxdsenateseats-27-50 |
| 51 | 15¢ | +1pp | $14K | kalshi | /markets/will-the-democratic-party-hold-51-seats-in-the-120-kalshi-kxdsenateseats-27-51 |
| 49 | 15¢ | +2pp | $250 | kalshi | /markets/will-the-democratic-party-hold-49-seats-in-the-120-kalshi-kxdsenateseats-27-49 |
| 48 | 10¢ | +1pp | $0 | kalshi | /markets/will-the-democratic-party-hold-48-seats-in-the-120-kalshi-kxdsenateseats-27-48 |
| 45 | 10¢ | +7pp | $0 | kalshi | /markets/will-the-democratic-party-hold-exactly-45-senate-s-kalshi-kxdsenateseats-29-e45 |
| 52 | 9¢ | −1pp | $1K | kalshi | /markets/will-the-democratic-party-hold-52-seats-in-the-120-kalshi-kxdsenateseats-27-52 |
| Below 45 | 9¢ | −3pp | $0 | kalshi | /markets/will-the-democratic-party-hold-fewer-than-45-senat-kalshi-kxdsenateseats-29-b45 |
| Above 56 | 8¢ | −3pp | $0 | kalshi | /markets/will-the-democratic-party-hold-more-than-56-senate-kalshi-kxdsenateseats-29-a56 |
| Below 45 | 7¢ | +1pp | $0 | kalshi | /markets/will-the-democratic-party-hold-less-than-45-seats-kalshi-kxdsenateseats-27-below45 |
| 49 | 7¢ | −1pp | $0 | kalshi | /markets/will-the-democratic-party-hold-exactly-49-senate-s-kalshi-kxdsenateseats-29-e49 |
| 50 | 7¢ | ±0 | $0 | kalshi | /markets/will-the-democratic-party-hold-exactly-50-senate-s-kalshi-kxdsenateseats-29-e50 |
| 47 | 6¢ | −1pp | $0 | kalshi | /markets/will-the-democratic-party-hold-47-seats-in-the-120-kalshi-kxdsenateseats-27-47 |
| 48 | 6¢ | +3pp | $0 | kalshi | /markets/will-the-democratic-party-hold-exactly-48-senate-s-kalshi-kxdsenateseats-29-e48 |
| 51 | 6¢ | ±0 | $0 | kalshi | /markets/will-the-democratic-party-hold-exactly-51-senate-s-kalshi-kxdsenateseats-29-e51 |
| 47 | 5¢ | −1pp | $0 | kalshi | /markets/will-the-democratic-party-hold-exactly-47-senate-s-kalshi-kxdsenateseats-29-e47 |
| 52 | 5¢ | ±0 | $0 | kalshi | /markets/will-the-democratic-party-hold-exactly-52-senate-s-kalshi-kxdsenateseats-29-e52 |
| 46 | 4¢ | +1pp | $0 | kalshi | /markets/will-the-democratic-party-hold-exactly-46-senate-s-kalshi-kxdsenateseats-29-e46 |
| 46 | 3¢ | — | $0 | kalshi | /markets/will-the-democratic-party-hold-46-seats-in-the-120-kalshi-kxdsenateseats-27-46 |

## 30-day trajectory

| Day | Above 52 | 50 | 51 |
|---|---|---|---|
| 2026-05-13 | — | — | 15 |
| 2026-05-14 | 20 | — | — |
| 2026-05-21 | — | 15 | 16 |
| 2026-05-25 | 22 | — | 15 |
| 2026-06-01 | 20 | — | — |
| 2026-06-02 | 21 | — | 14 |
| 2026-06-03 | 20 | 16 | — |
| 2026-06-07 | 20 | — | 15 |

_15 days of price history captured. Each row is the daily mean of intraday 5-min captures._

## What moved the line

- 2026-06-02 · 45 +7pp 3→10¢ · kalshi
- 2026-06-01 · Above 56 −3pp 11→8¢ · kalshi
- 2026-06-04 · Below 45 −3pp 12→9¢ · kalshi

## Analysis

This probability reflects the chance that Democrats will control fewer than 45 Senate seats following the 2026 midterm elections. The current 34% estimate reflects expectations that Democrats will likely retain Senate control or remain competitive, though significant uncertainty remains. The probability is primarily driven by historical midterm patterns favoring the opposition party and the electoral map, which features both Democratic-leaning seats in swing states and Republican-held seats in unfavorable terrain. The resolution depends entirely on the November 2026 midterm election results, which will determine the final Senate composition of the 120th Congress. Notably, related markets show substantial disagreement—Polymarket implies a much higher probability of Democratic underperformance than Kalshi, suggesting traders disagree on either baseline Senate dynamics or specific race outcomes.

### Key factors

- Current Senate composition and which seats are up for election in 2026 will mechanically constrain the range of possible outcomes
- Historical midterm patterns show the party holding the presidency typically loses Senate seats, but magnitude varies significantly based on economic conditions and approval ratings
- The 39-point spread between Polymarket and Kalshi contracts suggests material disagreement on Democratic performance, possibly reflecting different assumptions about candidate quality, turnout, or national environment
- Senate race-specific data points like the South Carolina Democratic market priced at 15¢ indicate expected losses in certain red-state Democratic seats
- The Democratic-majority prediction market (84¢ on Kalshi) implies traders expect Democrats to hold the chamber overall, making a sub-45-seat outcome a tail risk scenario

## 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

- HTML: https://simplefunctions.dev/odds/dsenateseats
- JSON: https://simplefunctions.dev/api/public/odds?slug=dsenateseats
- Topic hub: https://simplefunctions.dev/predictions/election-2026

## License

CC-BY-4.0. Attribute "SimpleFunctions" with a link to https://simplefunctions.dev. See https://simplefunctions.dev/legal for terms.