Combined depth · both venues
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48 75.9%
Next is 47 at 11.8%. The venues differ most on 44 (Polymarket 3.3%, Kalshi 0.1%), a 3.1-point gap.
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.
Prices come from our regular polls of each venue, the oldest 3 min ago. Ages are as of when this page was built.
Payoffs match in ordinary outcomes; see the rule differences below the table.
No arbitrage: the best bid elsewhere is 78¢, at or below the cheapest ask of 79¢.
Payoffs match in ordinary outcomes; see the rule differences below the table.
No arbitrage: the best bid elsewhere is 11¢, at or below the cheapest ask of 13¢.
Labels suggest the same named outcome; no persisted outcome identity or settlement parity is verified.
No arbitrage: the best bid elsewhere is 1.1¢, at or below the cheapest ask of 2.8¢.
Payoffs match in ordinary outcomes; see the rule differences below the table.
No arbitrage: the best bid elsewhere is 1.1¢, at or below the cheapest ask of 2.6¢.
Payoffs match in ordinary outcomes; see the rule differences below the table.
Buying on Kalshi at 0.9¢ and selling on Polymarket at 1.1¢ nets 20 bps before fees.
Payoffs match in ordinary outcomes; see the rule differences below the table.
Buying on Kalshi at 1¢ and selling on Polymarket at 1.2¢ nets 20 bps before fees.
Possible arbitrage before fees: buy 44 on Kalshi at 0.9¢, sell on Polymarket at 1.1¢ (20 bps). Check the rules below before trading. See all live spreads
Summarized from each venue’s published rules; the venue’s own rules page is the final word.
The top 3 outcomes on both venues, with the consensus between them. Hover for exact values.
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.
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.
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Enter a stake to see where it buys the most after fees, using each venue’s live order book.
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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.
Live prediction market odds for "How many House seats will the Democrats win in California?". 48 leads at 75.9%. Next is 47 at 11.8%. $56K has traded across 9 outcomes on Polymarket and Kalshi. The market is expected to resolve by Nov 4, 2026.
This market will resolve according to the number of seats in the US House of Representatives won by the Democratic Party in California in the 2026 United States midterm election. All California US House of Representatives elections held as part of the 2026 United States midterm election that elect voting members and determine representation in the upcoming 120th congress are included. Special elections to fill a vacancy for the remainder of an unexpired term are not included, whether or not held concurrently with the 2026 United States midterm election. Runoffs for qualifying elections will determine attribution of the relevant seat. Seats are attributed to the party under which the member was elected. If a member-elect changes party affiliation or vacates their seat after the date of the 2026 United States midterm election, the seat is attributed to the party under which the member was elected. Members of the House elected as independents who formally caucus, or who announce their intent to caucus, with a party prior to the date of the 2026 United States midterm election are included in that party’s count. If the caucus decisions of relevant members of the US House of Representatives elected as independents cannot be determined as of the date of the 2026 United States midterm 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.
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%.
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.
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.
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.
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.