Polymarket’s midterm odds converge as Democrats gain ground in Senate pricing

Polymarket’s separate House, Senate and balance-of-power markets aligned to within half a point of one another on the morning of November 2, according to DEV. The convergence came the day before the midterm vote.

Democrats were priced at 94.5 percent for the House and 71.5 percent for the Senate. Those figures put the party’s House prospects substantially above its Senate prospects, even as the separate markets produced closely aligned readings.

Senate pricing shifts in the final week

The Democratic Senate price increased from 64.5 percent on October 26 to 71.5 percent on November 2, according to DEV. That represents a seven-point rise in the final week.

The supplied summary does not give an earlier House price or the individual balance-of-power prices. It therefore supports a comparison of the Senate’s weekly movement and the markets’ reported alignment, but not a full reconstruction of how all three markets changed.

What it means for prediction markets

• Cross-market consistency: The reported gap of no more than half a point indicates close agreement among the separate markets’ implied outcomes, not identical Democratic odds for the House and Senate.
• Late Senate repricing: The seven-point increase marks a notable shift toward Democrats between October 26 and November 2.
• Agreement is not confirmation: Closely aligned prices reflect consistency across markets; they do not establish whether the election outcomes will match those probabilities.