Incumbent Rep. Mike Thompson (D) and challenger Eric Jones (D) dominate trader consensus to advance from California's top-two primary on June 2 in the solidly Democratic 4th Congressional District (D+17 PVI after 2025 redistricting via Proposition 50), thanks to their superior fundraising—Jones raised $2.6 million and Thompson $2 million through late 2025, dwarfing the six underfunded Republicans' combined totals under $150,000. The certified candidate list released March 26 confirmed nine contenders, including independents, amid a fragmented GOP field prone to vote-splitting that has historically sent one Democrat and one Republican forward since 2016. The Democratic Party of California endorsed Thompson for his regional advocacy on wildfires and wine industry issues, while Our Revolution backed Jones's progressive push against corporate influence; no public polls yet, with early voting approaching in late May.