The Prediction Markets

Which party will win the Senate in 2026?

Starts in 12 daysKickoff
Traded
$24.6M
Venues
Polymarket, Kalshi
Prices updated
7 h ago
Share

What the markets expect

Democratic 66.7%

Next is Republican at 33.3%. The venues differ most on Republican (Polymarket 32.5%, Kalshi 34%), a 1.5-point gap.

Democratic 66.7%Republican 33.3%

Odds by venue

Fair chance strips out each venue’s built-in margin (its prices add up to more than 100%), then blends the venues by how much has traded there, so the outcomes add up to 100%. Best Yes price is the cheapest ask across venues, and the payout is what a winning $100 stake returns before fees. Open a row for each venue’s contract name, bid and ask, and how closely their rules match.

2 of 4 prices are live from the exchange feeds; the rest come from our regular price polls, the oldest 8 h ago. Ages are as of when this page was built.

  • Polymarket
  • Kalshi
Democratic
66.7%
Polymarket 67.5%live, 7 h agoKalshi 67%(66.3% fair)live, 7 h agoBest Yes 67¢ on Kalshi, $100 pays $149 (1.49x)
Polymarket
Contract
Democratic Party
Price
67.5%
As of
Live feed, 7 h ago
Buy Yes
68¢
Sell Yes
67¢
$100 on Yes pays
$147 (1.47x)
Volume
$4.4M
Trade this on Polymarket
Kalshi
Contract
Democratic Party
Price
67%
Fair, margin removed
66.3%
As of
Live feed, 7 h ago
Buy Yes
67¢
Sell Yes
66¢
$100 on Yes pays
$149 (1.49x)
Volume
$7.5M
Trade this on Kalshi
Partial parity

Payoffs match in ordinary outcomes; see the rule differences below the table.

Prices on these venues are 7 h old, too old to show an executable spread.

Republican
33.3%
Polymarket 32.5%polled, 8 h agoKalshi 34%polled, 8 h agoBest Yes 33¢ on Polymarket, $100 pays $303 (3.03x)
Polymarket
Contract
Republican Party
Last price
32.5%
As of
Polled 8 h ago
Buy Yes
33¢
Sell Yes
32¢
$100 on Yes pays
$303 (3.03x)
Volume
$3.3M
Trade this on Polymarket
Kalshi
Contract
Republican Party
Last price
34%
As of
Polled 8 h ago
Buy Yes
34¢
Sell Yes
33¢
$100 on Yes pays
$294 (2.94x)
Volume
$9.3M
Trade this on Kalshi
Partial parity

Payoffs match in ordinary outcomes; see the rule differences below the table.

Prices on these venues are 8 h old, too old to show an executable spread.

Venue prices are 7 h old, so we are not showing a cross-venue spread. Check each venue for current prices. Find markets with fresh spreads

Mostly the same bet: 4 differences

Where they differ

  • Kalshi: media-consensus call, otherwise the party of the Speaker / President pro tempore on Feb 1 of the new Congress. Polymarket: majority of voting seats as elected, independents by caucus.
  • Tied Senate: Polymarket awards the Vice President's party; Kalshi follows the President pro tempore.
  • Members switching party after election day change the Kalshi outcome but not Polymarket's.
  • Trading closes at different times: Nov 3, 2026, 11:59 PM UTC on Polymarket and Feb 1, 2027, 3:00 PM UTC on Kalshi.
Polymarket
Polymarket resolves via:
UMA optimistic oracle
Kalshi
Kalshi resolves via:
Kalshi (CFTC-regulated exchange), source: Library of Congress
Show full rule comparison
  • Kalshi: media-consensus call, otherwise the party of the Speaker / President pro tempore on Feb 1 of the new Congress. Polymarket: majority of voting seats as elected, independents by caucus.
  • Tied Senate: Polymarket awards the Vice President's party; Kalshi follows the President pro tempore.
  • Members switching party after election day change the Kalshi outcome but not Polymarket's.
  • Trading closes Nov 3, 2026, 11:59 PM UTC on Polymarket and Feb 1, 2027, 3:00 PM UTC on Kalshi.

Summarized from each venue’s published rules; the venue’s own rules page is the final word.

How the odds have moved

The top 2 outcomes on both venues, with the consensus between them. Hover for exact values.

  • Democratic
  • Republican

Live prices for Democratic

What it costs to buy Yes, what you would get selling it, and the last trade on each exchange, updating as orders change. Hover a status for timing details.

Order books

Each venue’s resting orders for the selected outcome’s Yes contract, side by side. Top of book streams live; depth refreshes every 15 seconds.

Combined depth · both venues

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Depth · top 8 levels

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Recent trades

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What your stake buys

Enter a stake to see where it buys the most after fees, using each venue’s live order book.

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Cover all 2 outcomes across venues

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Buys at the asks resting now (taker orders), cheapest after fees first, from order-book snapshots up to 15 seconds old. Fees: Kalshi 0.07 × price × (1 − price) per share, rounded up to the cent; Polymarket 0.04 × price × (1 − price) per share (politics rate). Fee calculator. Estimates only, not advice.

About this market

Live prediction market odds for "Which party will win the Senate in 2026?". Democratic leads at 66.7%. Next is Republican at 33.3%. $24.6M has traded across 2 outcomes on Kalshi and Polymarket. The market is expected to resolve by Nov 3, 2026.

This market will resolve according to the party that wins control of the United States Senate in the 2026 United States midterm election. A party wins control of the United States Senate if it wins a majority of the chamber’s voting seats. If no party wins a majority of voting seats, the party that wins control of the chamber is the party that wins half of the voting seats and holds the Vice Presidency. If the outcome remains ambiguous after applying the above criteria, the chamber will be deemed controlled by the party with which the first selected President Pro Tempore of the Congress that convenes after the specified election is affiliated. The following rules govern the counting of seats for determining which party wins control of the chamber. All regular and special Senate elections that determine representation in the upcoming 120th Congress and are scheduled to take place in November 2026 as of October 31, 2026 are included. Runoffs for qualifying elections will determine attribution of the relevant seat, even if they take place after November 2026. Vacant seats for which no election or special election to fill the seat is scheduled to take place in November 2026 as of October 31, 2026 will be treated as held by the party affiliation of the most recent member to hold that seat. For seats contested in the specified election, seats are attributed to the party under which the member was elected. If a member-elect changes party affiliation, or vacates their seat, between election day and the formal organization of Congress, the seat is attributed to the party under which the member was elected. For seats not contested in the specified election, seats are attributed to the party that holds the seat as of the date of the election. If a current sitting member of the U.S. Senate who is not up for election changes party affiliation or vacates their seat after the date of the election, the seat is attributed to the party under which the member was affiliated at the time of the election. Senate members elected as independents who formally caucus with, or, for newly elected members, who announce their intent to caucus with, a party are included in that party’s count. If the caucus decisions of members of the Senate elected as independents cannot be determined on the date of the election, this market may remain open until the earlier of (i) an announcement from the relevant members of their intents to caucus, or (ii) January 4th, 11:59 PM ET of the following calendar year. If no such announcement is made by January 4th, 11:59 PM ET of the following calendar year, the member will not count towards the seat count of any party. The resolution sources for this market will be official information from relevant state electoral authorities, the United States Congress, and a consensus of credible reporting.

Questions

What does the consensus price mean?

It is the price of a Yes contract that pays $1 if the outcome happens. A 14¢ price means traders put the chance near 14%. Where two venues list the same outcome, we blend their last prices, weighting the venue with more trading volume more heavily (neither counts for less than a quarter). When only one outcome can win, each venue’s prices add up to a little over 100% (its margin); the fair chance removes that margin so the outcomes add up to exactly 100%.

How is the payout worked out?

A Yes contract pays $1 if it wins, so at the best ask a $100 stake buys 100 ÷ ask contracts. At 18¢ that is about 555 contracts, paying $556 (5.56x) if Yes happens. Venue fees and price slippage on larger orders are not included.

Why do the venues show different prices?

Each venue has its own traders, fees and order book. Contracts can also settle on slightly different terms, which is why each row lists how closely the rules match.

Is a price gap an arbitrage?

Only when you can buy Yes on one venue below what someone pays for Yes on the other, after fees, and both contracts settle the same way. We show the executable bid and ask so you can check.

How fresh are these prices?

Venue prices refresh every few minutes, and the order book and live quotes stream continuously. Each venue’s card shows when we last observed it.

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