Democratic incumbent Jim Costa advanced from the June 2, 2026 primary with 42.2% of the vote, ahead of Republican Kyle Kirkland at 26.4%, setting up a general election matchup on November 3. Nonpartisan forecasters including the Cook Political Report, Inside Elections, and Sabato’s Crystal Ball rate CA-21 as Likely Democratic, reflecting the district’s Central Valley demographics, post-redistricting boundaries, and Costa’s long incumbency advantage. Trader consensus at 87.5% for Democrats aligns with these assessments and historical performance in the seat, though the general election remains months away and subject to shifts from national conditions or turnout patterns.
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
NEW
NEW
Nov 3, 2026
Democratic Party
89%
Republican Party
12%
NEW
NEW
Nov 3, 2026
Democratic Party
$3,711 Vol.
89%
Republican Party
$3,849 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/).Democratic incumbent Jim Costa advanced from the June 2, 2026 primary with 42.2% of the vote, ahead of Republican Kyle Kirkland at 26.4%, setting up a general election matchup on November 3. Nonpartisan forecasters including the Cook Political Report, Inside Elections, and Sabato’s Crystal Ball rate CA-21 as Likely Democratic, reflecting the district’s Central Valley demographics, post-redistricting boundaries, and Costa’s long incumbency advantage. Trader consensus at 87.5% for Democrats aligns with these assessments and historical performance in the seat, though the general election remains months away and subject to shifts from national conditions or turnout patterns.
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/).
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
$7,561End 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 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/).Democratic incumbent Jim Costa advanced from the June 2, 2026 primary with 42.2% of the vote, ahead of Republican Kyle Kirkland at 26.4%, setting up a general election matchup on November 3. Nonpartisan forecasters including the Cook Political Report, Inside Elections, and Sabato’s Crystal Ball rate CA-21 as Likely Democratic, reflecting the district’s Central Valley demographics, post-redistricting boundaries, and Costa’s long incumbency advantage. Trader consensus at 87.5% for Democrats aligns with these assessments and historical performance in the seat, though the general election remains months away and subject to shifts from national conditions or turnout patterns.
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/).
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
$7,561End Date
Nov 3, 2026Market Opened
Jan 28, 2026, 12:08 AM ETResolver
0x2F5e3684c...Democratic incumbent Jim Costa advanced from the June 2, 2026 primary with 42.2% of the vote, ahead of Republican Kyle Kirkland at 26.4%, setting up a general election matchup on November 3. Nonpartisan forecasters including the Cook Political Report, Inside Elections, and Sabato’s Crystal Ball rate CA-21 as Likely Democratic, reflecting the district’s Central Valley demographics, post-redistricting boundaries, and Costa’s long incumbency advantage. Trader consensus at 87.5% for Democrats aligns with these assessments and historical performance in the seat, though the general election remains months away and subject to shifts from national conditions or turnout patterns.
Experimental AI-generated summary referencing Polymarket data. This is not trading advice and plays no role in how this market resolves. · Updated
Beware of external links.
Beware of external links.
Frequently Asked Questions