Senate is still a tossup, but Democrats now have slight edge, prediction market traders think

• Democrats need to flip several states that Trump won by 10% or more in 2024, including Alaska, Texas, and Ohio, with Republicans defending 20 of 33 Senate seats up for election
• Democratic odds improved from roughly 40% before the Feb. 28 U.S.-Iran war to current 54-59% levels, driven by falling Trump approval ratings and economic concerns
• A recent poll shows likely voters favoring Democratic congressional candidates by nearly 9 percentage points nationwide, with gas prices above $4/gallon and diesel at all-time highs hurting GOP prospects

Summary: Senate Control Prediction Markets Favor Democrats

Key Development:

Prediction market traders now give Democrats a slight edge in the 2026 U.S. Senate race, with Kalshi showing 54% odds and Polymarket indicating 59% probability that Democrats will win control from Republicans.

Political Landscape:

Republicans currently defend 20 of 33 Senate seats up for election. Democrats face a challenging path requiring victories in states where President Trump won by 10+ percentage points in 2024, including Alaska, Texas, and Ohio.

Market Shift Timeline:

• Pre-February 28: Republicans held ~60% odds on both platforms
• Late February: Democratic odds improved significantly following the start of the U.S.-Iran war
• April: Democrats briefly took the lead
• May-Summer: GOP chances recovered as the U.S.-Iran conflict eased, relieving gas price pressures
• Recent weeks: Democratic odds strengthened again

Economic Factors:

Rising energy costs are impacting Republican prospects:

• U.S. oil prices: Above $100 per barrel
• National gasoline average: Over $4 per gallon
• Diesel prices: All-time highs

These factors have driven down Trump's approval ratings, correlating with improved Democratic Senate prospects.

Polling Data:

A recent poll shows likely voters nationwide favor Democratic congressional candidates by approximately 9 percentage points, indicating a favorable environment for Democrats heading into November elections.

Note: CNBC has a commercial relationship with Kalshi, including customer acquisition and minority investment.