Incumbent Democratic Representative Jim Costa advanced from the June 2026 top-two primary alongside Republican Kyle Kirkland to contest the November general election in California’s 21st district. The seat carries a Cook Partisan Voter Index of D+5 and receives Likely Democratic or Safe Democratic ratings from major forecasters, reflecting its Central Valley voter base and registration edge for Democrats. These structural factors underpin the 91.5% implied probability traders assign to a Democratic victory. A realistic challenge would require an unexpected national Republican surge, sharply reduced Democratic turnout, or late developments such as a significant scandal or health issue affecting the incumbent that alter the race dynamics before Election Day.
Experimental AI-generated summary referencing Polymarket data. This is not trading advice and plays no role in how this market resolves. · UpdatedCA-21 House Election Winner
CA-21 House Election Winner
$24,749 Vol.
$24,749 Vol.
Nov 2, 2026
Democratic Party
92%
Republican Party
9%
$24,749 Vol.
$24,749 Vol.
Nov 2, 2026
Democratic Party
$14,407 Vol.
92%
Republican Party
$10,342 Vol.
9%
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 3, 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 Democratic Representative Jim Costa advanced from the June 2026 top-two primary alongside Republican Kyle Kirkland to contest the November general election in California’s 21st district. The seat carries a Cook Partisan Voter Index of D+5 and receives Likely Democratic or Safe Democratic ratings from major forecasters, reflecting its Central Valley voter base and registration edge for Democrats. These structural factors underpin the 91.5% implied probability traders assign to a Democratic victory. A realistic challenge would require an unexpected national Republican surge, sharply reduced Democratic turnout, or late developments such as a significant scandal or health issue affecting the incumbent that alter the race dynamics before Election Day.
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 3, 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/).
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/).
Market Opened: Jan 28, 2026, 12:08 AM ET
Volume
$24,749End Date
Nov 3, 2026Market Opened
Jan 28, 2026, 12:08 AM ETResolver
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 3, 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 Democratic Representative Jim Costa advanced from the June 2026 top-two primary alongside Republican Kyle Kirkland to contest the November general election in California’s 21st district. The seat carries a Cook Partisan Voter Index of D+5 and receives Likely Democratic or Safe Democratic ratings from major forecasters, reflecting its Central Valley voter base and registration edge for Democrats. These structural factors underpin the 91.5% implied probability traders assign to a Democratic victory. A realistic challenge would require an unexpected national Republican surge, sharply reduced Democratic turnout, or late developments such as a significant scandal or health issue affecting the incumbent that alter the race dynamics before Election Day.
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 3, 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/).
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
$24,749End Date
Nov 3, 2026Market Opened
Jan 28, 2026, 12:08 AM ETResolver
0x2F5e3684c...Incumbent Democratic Representative Jim Costa advanced from the June 2026 top-two primary alongside Republican Kyle Kirkland to contest the November general election in California’s 21st district. The seat carries a Cook Partisan Voter Index of D+5 and receives Likely Democratic or Safe Democratic ratings from major forecasters, reflecting its Central Valley voter base and registration edge for Democrats. These structural factors underpin the 91.5% implied probability traders assign to a Democratic victory. A realistic challenge would require an unexpected national Republican surge, sharply reduced Democratic turnout, or late developments such as a significant scandal or health issue affecting the incumbent that alter the race dynamics before Election Day.
Experimental AI-generated summary referencing Polymarket data. This is not trading advice and plays no role in how this market resolves. · Updated
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