How Polymarket and Kalshi price control of the U.S. Senate after the 2026 midterms — the same event on two platforms, with settlement rules explained. Data-only research, not trading advice.
PolyKal Research · Published 2026-09-28 · Data as of 2026-10-12 22:28 ET · Independent research, not affiliated with Polymarket or Kalshi. Not trading advice.
Which party holds a majority after Nov 3 · trader prices, not forecasts
Gap 2.0 ptsas of 02:25 UTC
As of 2026-10-12, Polymarket's most-likely Senate control outcome is “Democratic Party” at 63.5%.
After fees, Polymarket is cheaper on “Republican Party”; Kalshi is cheaper on “Democratic Party”, so the cheaper venue flips by outcome — that fits each platform's fee schedule and liquidity more than a real disagreement.
For the same “Democratic Party” outcome, Kalshi is currently cheaper after fees. The market's read right now is “Democratic Party” at 63.5%. To follow which party controls the Senate on November 3, generic-ballot polling and the closest state races (e.g. North Carolina, Maine, and Texas) are commonly watched. This page helps you read the board and compare costs — it does not tell you which side to take.
Market prices for the leading option in each race. No ratings, no poll averages, no "likely winner".
No races match this filter.
Checked = market and rule text checked by hand on both platforms; Auto-matched = paired automatically by state, office and date; Market missing = no option is listed on both platforms. Gap = difference between the two platforms' prices for the same option.
Trader prices, not probabilities. No events are drawn on this chart.
| Day (UTC) | Polymarket | Kalshi |
|---|---|---|
| 2026-10-13 | 63.5% | — |
| 2026-10-12 | 63.5% | 61.0% |
| 2026-10-11 | 62.5% | 60.0% |
| 2026-10-10 | 62.5% | 60.0% |
| 2026-10-09 | 62.5% | 62.0% |
| 2026-10-08 | 64.5% | 63.0% |
| 2026-10-07 | 64.5% | 64.0% |
| 2026-10-06 | 65.5% | 65.0% |
| 2026-10-05 | 67.5% | 63.0% |
| 2026-10-04 | 64.5% | 64.0% |
| 2026-10-03 | 64.5% | 63.0% |
| 2026-10-02 | 62.5% | 63.0% |
| 2026-10-01 | 62.5% | 63.0% |
| 2026-09-30 | 62.5% | 62.0% |
| 2026-09-29 | 62.5% | 62.0% |
| 2026-09-28 | 62.5% | 62.0% |
| 2026-09-27 | 62.5% | 62.0% |
| 2026-09-26 | 62.5% | 62.0% |
| 2026-09-25 | 62.5% | 61.0% |
| 2026-09-24 | 66.5% | 65.0% |
| 2026-09-23 | 65.5% | 63.0% |
| 2026-09-22 | 63.5% | 61.0% |
| 2026-09-21 | 60.5% | 60.0% |
| 2026-09-20 | 60.5% | 60.0% |
| 2026-09-19 | 60.5% | 59.0% |
| 2026-09-18 | 59.5% | 59.0% |
| 2026-09-17 | 58.5% | 56.0% |
| 2026-09-16 | 58.5% | 55.0% |
| 2026-09-15 | 53.5% | 52.0% |
| 2026-09-14 | 52.5% | 49.0% |
Daily prices from each platform's public price history (Polymarket daily prices, Kalshi daily candles), fetched when the page is built. Prices freeze 2026-11-03 22:30 UTC and are never replaced by settlement prices.
Prices use the same method as the Midterms pages: Polymarket shows the market's displayed Yes price. Kalshi shows the midpoint of the best Yes bid and ask when they are within 8¢ of each other, and otherwise the best Yes bid. Outcomes with no Yes bid show —.
Per-contract cost to buy Yes, taker fees from Fee schedule. Try your own size in the fee calculator.
Polymarket is cheaper on “Republican Party” after fees; Kalshi is cheaper on “Democratic Party”. The cheaper venue flips by outcome, which usually reflects each platform's fee schedule and where liquidity sits rather than a real disagreement. Work any size in the fee calculator; dated rates on the fee schedule.
Where each number on this page comes from, and what each status label means.
PolyKal Research. “2026 Senate control: how Polymarket and Kalshi compare.” PolyKal Research, September 28, 2026. https://polykal.net/topics/senate-control-2026/ (accessed the date you view this page).
How Polymarket and Kalshi price control of the U.S. Senate after the 2026 midterms — the same event on two platforms, with settlement rules explained. Data-only research, not trading advice.
PolyKal Research · Published 2026-09-28 · Data as of 2026-10-12 22:28 ET · Independent research, not affiliated with Polymarket or Kalshi. Not trading advice.
Which party holds a majority after Nov 3 · trader prices, not forecasts
Gap 2.0 ptsas of 02:25 UTC
As of 2026-10-12, Polymarket's most-likely Senate control outcome is “Democratic Party” at 63.5%.
After fees, Polymarket is cheaper on “Republican Party”; Kalshi is cheaper on “Democratic Party”, so the cheaper venue flips by outcome — that fits each platform's fee schedule and liquidity more than a real disagreement.
For the same “Democratic Party” outcome, Kalshi is currently cheaper after fees. The market's read right now is “Democratic Party” at 63.5%. To follow which party controls the Senate on November 3, generic-ballot polling and the closest state races (e.g. North Carolina, Maine, and Texas) are commonly watched. This page helps you read the board and compare costs — it does not tell you which side to take.
Market prices for the leading option in each race. No ratings, no poll averages, no "likely winner".
No races match this filter.
Checked = market and rule text checked by hand on both platforms; Auto-matched = paired automatically by state, office and date; Market missing = no option is listed on both platforms. Gap = difference between the two platforms' prices for the same option.
Trader prices, not probabilities. No events are drawn on this chart.
| Day (UTC) | Polymarket | Kalshi |
|---|---|---|
| 2026-10-13 | 63.5% | — |
| 2026-10-12 | 63.5% | 61.0% |
| 2026-10-11 | 62.5% | 60.0% |
| 2026-10-10 | 62.5% | 60.0% |
| 2026-10-09 | 62.5% | 62.0% |
| 2026-10-08 | 64.5% | 63.0% |
| 2026-10-07 | 64.5% | 64.0% |
| 2026-10-06 | 65.5% | 65.0% |
| 2026-10-05 | 67.5% | 63.0% |
| 2026-10-04 | 64.5% | 64.0% |
| 2026-10-03 | 64.5% | 63.0% |
| 2026-10-02 | 62.5% | 63.0% |
| 2026-10-01 | 62.5% | 63.0% |
| 2026-09-30 | 62.5% | 62.0% |
| 2026-09-29 | 62.5% | 62.0% |
| 2026-09-28 | 62.5% | 62.0% |
| 2026-09-27 | 62.5% | 62.0% |
| 2026-09-26 | 62.5% | 62.0% |
| 2026-09-25 | 62.5% | 61.0% |
| 2026-09-24 | 66.5% | 65.0% |
| 2026-09-23 | 65.5% | 63.0% |
| 2026-09-22 | 63.5% | 61.0% |
| 2026-09-21 | 60.5% | 60.0% |
| 2026-09-20 | 60.5% | 60.0% |
| 2026-09-19 | 60.5% | 59.0% |
| 2026-09-18 | 59.5% | 59.0% |
| 2026-09-17 | 58.5% | 56.0% |
| 2026-09-16 | 58.5% | 55.0% |
| 2026-09-15 | 53.5% | 52.0% |
| 2026-09-14 | 52.5% | 49.0% |
Daily prices from each platform's public price history (Polymarket daily prices, Kalshi daily candles), fetched when the page is built. Prices freeze 2026-11-03 22:30 UTC and are never replaced by settlement prices.
Prices use the same method as the Midterms pages: Polymarket shows the market's displayed Yes price. Kalshi shows the midpoint of the best Yes bid and ask when they are within 8¢ of each other, and otherwise the best Yes bid. Outcomes with no Yes bid show —.
Per-contract cost to buy Yes, taker fees from Fee schedule. Try your own size in the fee calculator.
Polymarket is cheaper on “Republican Party” after fees; Kalshi is cheaper on “Democratic Party”. The cheaper venue flips by outcome, which usually reflects each platform's fee schedule and where liquidity sits rather than a real disagreement. Work any size in the fee calculator; dated rates on the fee schedule.
Where each number on this page comes from, and what each status label means.
PolyKal Research. “2026 Senate control: how Polymarket and Kalshi compare.” PolyKal Research, September 28, 2026. https://polykal.net/topics/senate-control-2026/ (accessed the date you view this page).