CA-04 Primary Winners

Resolution Criteria

The California primary is currently scheduled to take place on June 2, 2026. This market will resolve "Yes" if the listed candidate advances from the primary to contest the seat for California's 4th congressional district in the U.S. House of Representatives in the 2026 midterm elections. Otherwise, this market will resolve to "No". If no nominees are announced by November 3, 2026, 11:59PM ET, this market will resolve to "Other". The resolution source for this market will be a consensus of official sources, including https://www.sos.ca.gov/. Any replacement of the nominees before election day will not change the resolution of the market.

Mike Thompson and Eric Jones are the heaviest-backed candidates to advance from the CA-04 primary to contest California's 4th congressional district in the 2026 midterm elections. Market volume is heavily concentrated on these two candidates, consistent with a two-seat primary structure where multiple candidates can advance. Resolution follows the official California primary on 2 June 2026, with the California Secretary of State as the source of truth.

Market structure

The market lists eight named candidates as separate yes/no outcomes. Volume is heavily concentrated on Mike Thompson and Eric Jones, with a small cluster of contenders — including Heath Fulkerson and Laurie MacKenzie — attracting some backing. The remaining candidates are lightly traded. Resolution requires official confirmation that a candidate advances from the primary. If no nominees are announced by 3 November 2026, all unresolved outcomes settle as 'Other'.

Background

California's 4th congressional district uses a top-two primary system, in which all candidates regardless of party appear on a single ballot and the two highest vote-getters advance to the November general election. This structure makes the primary itself the decisive contest for determining which candidates will compete for the seat. The district, covering parts of the Sacramento Valley and Sierra Nevada foothills, has historically leaned Republican but has seen competitive races in recent cycles. The 2026 midterm cycle takes place against a nationally charged political environment, with control of the House of Representatives again in contention. Candidate filing deadlines and ballot access rules administered by the California Secretary of State will govern who appears on the June ballot.

Key factors

California's top-two primary format means exactly two candidates advance regardless of party affiliation, which shapes how individual yes/no outcomes interact. Incumbent status, name recognition, and fundraising capacity are structural determinants of primary performance in congressional races. Candidate field size matters: a crowded field can split votes in ways that allow a less prominent candidate to advance if better-known candidates divide the same voter base. Filing deadlines could alter the field if candidates withdraw or are disqualified before the June vote. Local endorsements from party organisations, labour groups, and prominent officials can influence turnout among motivated primary voters. Any redistricting changes or legal challenges affecting the district boundaries before June 2026 would affect the voter pool. National party investment, including outside spending from congressional campaign committees, can shift momentum in the final weeks.

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