California's 21st congressional district favors the Democratic nominee due to post-redistricting boundaries that shifted the seat toward Democratic-leaning voter blocs in the Central Valley. Incumbent Representative Jim Costa advanced from the June 2026 top-two primary with 42 percent, ahead of Republican Kyle Kirkland at 26 percent, setting up a general election matchup on November 3. Nonpartisan ratings classify the race as solid or safe Democratic, reflecting the district's partisan baseline, Costa's incumbency and fundraising edge, and limited Republican crossover appeal. Traders assign the Democratic Party a 91.5 percent implied probability consistent with these structural factors. A late surge in Republican turnout, unexpected scandals, or major shifts in national midterm dynamics could still narrow the margin, though such developments remain low-probability based on current evidence.
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 3, 2026
Democratic Party
92%
Republican Party
9%
$24,749 Vol.
$24,749 Vol.
Nov 3, 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/).California's 21st congressional district favors the Democratic nominee due to post-redistricting boundaries that shifted the seat toward Democratic-leaning voter blocs in the Central Valley. Incumbent Representative Jim Costa advanced from the June 2026 top-two primary with 42 percent, ahead of Republican Kyle Kirkland at 26 percent, setting up a general election matchup on November 3. Nonpartisan ratings classify the race as solid or safe Democratic, reflecting the district's partisan baseline, Costa's incumbency and fundraising edge, and limited Republican crossover appeal. Traders assign the Democratic Party a 91.5 percent implied probability consistent with these structural factors. A late surge in Republican turnout, unexpected scandals, or major shifts in national midterm dynamics could still narrow the margin, though such developments remain low-probability based on current evidence.
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/).California's 21st congressional district favors the Democratic nominee due to post-redistricting boundaries that shifted the seat toward Democratic-leaning voter blocs in the Central Valley. Incumbent Representative Jim Costa advanced from the June 2026 top-two primary with 42 percent, ahead of Republican Kyle Kirkland at 26 percent, setting up a general election matchup on November 3. Nonpartisan ratings classify the race as solid or safe Democratic, reflecting the district's partisan baseline, Costa's incumbency and fundraising edge, and limited Republican crossover appeal. Traders assign the Democratic Party a 91.5 percent implied probability consistent with these structural factors. A late surge in Republican turnout, unexpected scandals, or major shifts in national midterm dynamics could still narrow the margin, though such developments remain low-probability based on current evidence.
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...California's 21st congressional district favors the Democratic nominee due to post-redistricting boundaries that shifted the seat toward Democratic-leaning voter blocs in the Central Valley. Incumbent Representative Jim Costa advanced from the June 2026 top-two primary with 42 percent, ahead of Republican Kyle Kirkland at 26 percent, setting up a general election matchup on November 3. Nonpartisan ratings classify the race as solid or safe Democratic, reflecting the district's partisan baseline, Costa's incumbency and fundraising edge, and limited Republican crossover appeal. Traders assign the Democratic Party a 91.5 percent implied probability consistent with these structural factors. A late surge in Republican turnout, unexpected scandals, or major shifts in national midterm dynamics could still narrow the margin, though such developments remain low-probability based on current evidence.
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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