**Redistricting under Proposition 50, approved by voters in November 2025, is the dominant driver of trader expectations for Democratic seat totals in California's 52 House districts.** The new legislatively drawn lines, effective for the 2026 cycle through 2030, shift several previously Republican-leaning Central Valley and Southern California districts toward Democrats, with analysts projecting a net gain of three to five seats relative to the 43 Democratic seats held after 2024. Post-primary developments reinforce this positioning. June 2026 primaries have clarified candidate fields in key battlegrounds, including CA-22 (held by David Valadao) and CA-48 (open after Darrell Issa's retirement), where adjusted boundaries and voter registration shifts favor Democratic performance. Broader midterm dynamics, including generic ballot trends and the typical opposition-party advantage in a president's second midterm, add modest upward pressure on totals in the high 40s. Market pricing clusters tightly around 47–49 seats because these structural changes outweigh remaining uncertainty in a handful of toss-up districts, while the low probability attached to outcomes below 46 or above 49 reflects limited expected variance absent major late-cycle shifts in turnout or national conditions.