Blue tsunami in 2026?: Odds & Probability

Prediction markets price a blue tsunami—Democrats holding at least 235 House seats and 51 Senate seats after the 2026 midterms—at 50.5%, a close to a coin flip.

50.5%-19.5 pts 24h

Updated · Volume $37.3K

36%50%63%77%Aug 21Aug 29Sep 5Sep 13Sep 20

The contract is designed around a single binary outcome; the 'No' side covers every scenario that falls short of a blue tsunami.

Context

Sep 20, 2026

Probability fell from 71.0% to 50.5% — a 20.5-point move over the past day.

Sep 19, 2026

Probability fell from 60.0% to 51.0% — a 9.0-point move over the past day.

Sep 18, 2026

Probability rose from 47.0% to 58.0% — a 11.0-point move over the past day.

Aug 19, 2026

Probability rose from 43.5% to 57.5% — a 14.0-point move over the past day.

The contract currently trades at 50.5% (updated 12 min ago). It has moved between 41.0% and 72.0% over the life of the market. To resolve to Yes, both of the following must occur from the 2026 midterms: Democrats win 235 or more House seats and 51 or more Senate seats. If either threshold is missed, the market resolves to No. Trading continues until one condition is conclusively unmet or both are met. Full terms are published at the Polymarket link. Resolution is determined solely by the official certified results of the 2026 U.S. House and Senate elections. The market’s end date is Jan 5, 2027.

FAQ

What counts as a blue tsunami in this market?

Democrats must hold at least 235 seats in the House of Representatives and at least 51 seats in the Senate after the 2026 midterm elections.

How does the market settle?

It resolves to Yes only if both congressional seat thresholds are met. If either condition fails, it resolves to No.

When does trading stop?

The market remains open until official results confirm that one of the conditions cannot be met or until both conditions are satisfied.

Where can I find the complete rules?

The full terms are available at the Polymarket link provided in the market description.

Data: Polymarket · Methodology · Not financial advice

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