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Politics·Nov 4 Elections

CA-21 House Election Winner

icon for CA-21 House Election Winner
Politics·Nov 4 Elections

CA-21 House Election Winner

NEW
Polymarket
NEW

Democratic Party

$953 Vol.

88%

Republican Party

$1,252 Vol.

12%

This market will resolve according to the party of the candidate who wins the CA-21 congressional district seat in the U.S. House of Representatives in the 2026 midterm elections. The midterm elections will take place on November 4, 2026. ​A candidate's party will be determined by their ballot-listed or otherwise identifiable affiliation with that party at the time all of the 2026 House elections are conclusively called by this market's resolution sources. A candidate without a ballot-listed affiliation to either the Democrat or Republican parties will be considered a member of one of these parties based on the party with which they most recently expressed their intent to caucus at the time all of the House elections are conclusively called by this market's resolution sources. This market will resolve based on the result of the election as indicated by a consensus of credible reporting. If there is ambiguity, this market will resolve based solely on the official results as reported by the United States government, specifically the Federal Election Commission (https://www.fec.gov/).Incumbent Democrat Jim Costa's reelection bid in California's 21st Congressional District, a D+4 Cook Partisan Voter Index seat that favored Kamala Harris by six points in 2024, anchors trader consensus at 87.5% for the Democratic Party ahead of the June 2 nonpartisan top-two primary. Costa's history of prevailing in competitive Central Valley races, including narrow 2024 wins over Republican challengers, combined with superior fundraising and a fragmented GOP field featuring businessman Kyle Kirkland and veteran Lorenzo Rios, sustains his frontrunner status. No recent polling disrupts this dynamic, though a strong GOP primary performance or turnout surge could narrow odds before the November 3 general election.

This market will resolve according to the party of the candidate who wins the CA-21 congressional district seat in the U.S. House of Representatives in the 2026 midterm elections. The midterm elections will take place on November 4, 2026.

​A candidate's party will be determined by their ballot-listed or otherwise identifiable affiliation with that party at the time all of the 2026 House elections are conclusively called by this market's resolution sources. A candidate without a ballot-listed affiliation to either the Democrat or Republican parties will be considered a member of one of these parties based on the party with which they most recently expressed their intent to caucus at the time all of the House elections are conclusively called by this market's resolution sources.

This market will resolve based on the result of the election as indicated by a consensus of credible reporting. If there is ambiguity, this market will resolve based solely on the official results as reported by the United States government, specifically the Federal Election Commission (https://www.fec.gov/).
Volume
$2,205
End Date
Nov 3, 2026
Market Opened
Jan 28, 2026, 12:08 AM ET

Resolver

0x2F5e3684c...
This market will resolve according to the party of the candidate who wins the CA-21 congressional district seat in the U.S. House of Representatives in the 2026 midterm elections. The midterm elections will take place on November 4, 2026. ​A candidate's party will be determined by their ballot-listed or otherwise identifiable affiliation with that party at the time all of the 2026 House elections are conclusively called by this market's resolution sources. A candidate without a ballot-listed affiliation to either the Democrat or Republican parties will be considered a member of one of these parties based on the party with which they most recently expressed their intent to caucus at the time all of the House elections are conclusively called by this market's resolution sources. This market will resolve based on the result of the election as indicated by a consensus of credible reporting. If there is ambiguity, this market will resolve based solely on the official results as reported by the United States government, specifically the Federal Election Commission (https://www.fec.gov/).
This market will resolve according to the party of the candidate who wins the CA-21 congressional district seat in the U.S. House of Representatives in the 2026 midterm elections. The midterm elections will take place on November 4, 2026. ​A candidate's party will be determined by their ballot-listed or otherwise identifiable affiliation with that party at the time all of the 2026 House elections are conclusively called by this market's resolution sources. A candidate without a ballot-listed affiliation to either the Democrat or Republican parties will be considered a member of one of these parties based on the party with which they most recently expressed their intent to caucus at the time all of the House elections are conclusively called by this market's resolution sources. This market will resolve based on the result of the election as indicated by a consensus of credible reporting. If there is ambiguity, this market will resolve based solely on the official results as reported by the United States government, specifically the Federal Election Commission (https://www.fec.gov/).Incumbent Democrat Jim Costa's reelection bid in California's 21st Congressional District, a D+4 Cook Partisan Voter Index seat that favored Kamala Harris by six points in 2024, anchors trader consensus at 87.5% for the Democratic Party ahead of the June 2 nonpartisan top-two primary. Costa's history of prevailing in competitive Central Valley races, including narrow 2024 wins over Republican challengers, combined with superior fundraising and a fragmented GOP field featuring businessman Kyle Kirkland and veteran Lorenzo Rios, sustains his frontrunner status. No recent polling disrupts this dynamic, though a strong GOP primary performance or turnout surge could narrow odds before the November 3 general election.

This market will resolve according to the party of the candidate who wins the CA-21 congressional district seat in the U.S. House of Representatives in the 2026 midterm elections. The midterm elections will take place on November 4, 2026.

​A candidate's party will be determined by their ballot-listed or otherwise identifiable affiliation with that party at the time all of the 2026 House elections are conclusively called by this market's resolution sources. A candidate without a ballot-listed affiliation to either the Democrat or Republican parties will be considered a member of one of these parties based on the party with which they most recently expressed their intent to caucus at the time all of the House elections are conclusively called by this market's resolution sources.

This market will resolve based on the result of the election as indicated by a consensus of credible reporting. If there is ambiguity, this market will resolve based solely on the official results as reported by the United States government, specifically the Federal Election Commission (https://www.fec.gov/).
Volume
$2,205
End Date
Nov 3, 2026
Market Opened
Jan 28, 2026, 12:08 AM ET

Resolver

0x2F5e3684c...
This market will resolve according to the party of the candidate who wins the CA-21 congressional district seat in the U.S. House of Representatives in the 2026 midterm elections. The midterm elections will take place on November 4, 2026. ​A candidate's party will be determined by their ballot-listed or otherwise identifiable affiliation with that party at the time all of the 2026 House elections are conclusively called by this market's resolution sources. A candidate without a ballot-listed affiliation to either the Democrat or Republican parties will be considered a member of one of these parties based on the party with which they most recently expressed their intent to caucus at the time all of the House elections are conclusively called by this market's resolution sources. This market will resolve based on the result of the election as indicated by a consensus of credible reporting. If there is ambiguity, this market will resolve based solely on the official results as reported by the United States government, specifically the Federal Election Commission (https://www.fec.gov/).

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Frequently Asked Questions

"CA-21 House Election Winner" is a prediction market on Polymarket with 2 possible outcomes where traders buy and sell shares based on what they believe will happen. The current leading outcome is "Democratic Party" at 88%, followed by "Republican Party" at 12%. Prices reflect real-time crowd-sourced probabilities. For example, a share priced at 88¢ implies that the market collectively assigns a 88% chance to that outcome. These odds shift continuously as traders react to new developments and information. Shares in the correct outcome are redeemable for $1 each upon market resolution.

"CA-21 House Election Winner" is a newly created market on Polymarket, launched on Jan 28, 2026. As an early market, this is your opportunity to be among the first traders to set the odds and establish the market's initial price signals. You can also bookmark this page to track volume and trading activity as the market gains traction over time.

To trade on "CA-21 House Election Winner," browse the 2 available outcomes listed on this page. Each outcome displays a current price representing the market's implied probability. To take a position, select the outcome you believe is most likely, choose "Yes" to trade in favor of it or "No" to trade against it, enter your amount, and click "Trade." If your chosen outcome is correct when the market resolves, your "Yes" shares pay out $1 each. If it's incorrect, they pay out $0. You can also sell your shares at any time before resolution if you want to lock in a profit or cut a loss.

The current frontrunner for "CA-21 House Election Winner" is "Democratic Party" at 88%, meaning the market assigns a 88% chance to that outcome. The next closest outcome is "Republican Party" at 12%. These odds update in real-time as traders buy and sell shares, so they reflect the latest collective view of what's most likely to happen. Check back frequently or bookmark this page to follow how the odds shift as new information emerges.

The resolution rules for "CA-21 House Election Winner" define exactly what needs to happen for each outcome to be declared a winner — including the official data sources used to determine the result. You can review the complete resolution criteria in the "Rules" section on this page above the comments. We recommend reading the rules carefully before trading, as they specify the precise conditions, edge cases, and sources that govern how this market is settled.