The Massachusetts 9th congressional district's consistent Democratic lean, reflected in its D+6 Partisan Voter Index and incumbent Bill Keating's 2024 reelection margin, underpins the 95.7% trader consensus for a Democratic winner. Race ratings from Cook Political Report, Sabato's Crystal Ball, and others classify the seat as solid or safe Democratic ahead of the November 3, 2026, general election. Keating faces a primary challenge on September 1 but holds the structural advantages of incumbency, fundraising, and limited Republican opposition from presumptive nominee Tyler MacAllister. Scenarios that could narrow the outcome include a major scandal affecting the Democratic nominee, unusually high Republican turnout, or a national political shift, though current fundamentals show few signs of such movement.
Experimental AI-generated summary referencing Polymarket data. This is not trading advice and plays no role in how this market resolves. · UpdatedMA-09 House Election Winner
$22,962 Vol.
$22,962 Vol.
Democratic Party
96%
Republican Party
5%
$22,962 Vol.
$22,962 Vol.
Democratic Party
96%
Republican Party
5%
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, 11:09 AM ET
Resolver
0x2F5e3684c...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/).
Resolver
0x2F5e3684c...The Massachusetts 9th congressional district's consistent Democratic lean, reflected in its D+6 Partisan Voter Index and incumbent Bill Keating's 2024 reelection margin, underpins the 95.7% trader consensus for a Democratic winner. Race ratings from Cook Political Report, Sabato's Crystal Ball, and others classify the seat as solid or safe Democratic ahead of the November 3, 2026, general election. Keating faces a primary challenge on September 1 but holds the structural advantages of incumbency, fundraising, and limited Republican opposition from presumptive nominee Tyler MacAllister. Scenarios that could narrow the outcome include a major scandal affecting the Democratic nominee, unusually high Republican turnout, or a national political shift, though current fundamentals show few signs of such movement.
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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