Democratic Senate odds hinge on differing contract structures across platforms
DeFi Rate explains in its sources page, observed at 6:09 p.m. ET, that Kalshi lists no single Senate control contract, so its price is built by adding the two balance of power outcomes in which Democrats win the Senate, at 73.5 cents and 0.55 cents. Its House average is 93.9 percent, from Kalshi at 93.25 percent and Polymarket at 94.5 percent.
Democrats’ average probability of winning Senate control stood at 74.8 percent in a snapshot observed at 6:09 p.m. ET, according to DeFi Rate. The figures appeared in an update published Nov 3, 2026, at 6:30 PM ET.
The Senate comparison put Kalshi at 74.1 percent and Polymarket at 75.5 percent. But the Kalshi figure was constructed from multiple outcomes rather than taken from a single Senate control contract.
How the comparison was assembled
According to DeFi Rate’s sources page, Kalshi lists no standalone Senate control contract. DeFi Rate instead added the prices of the two balance of power outcomes under which Democrats win the Senate, priced at 73.5 cents and 0.55 cents.
For House control, DeFi Rate reported a Democratic average of 93.9 percent, combining Kalshi’s 93.25 percent with Polymarket’s 94.5 percent. The House figures therefore showed a higher implied probability of Democratic control than the Senate comparison.
What it means for prediction markets
- Contract structure matters: Kalshi’s Senate reading is a combined measure of two balance of power outcomes, not a directly listed Senate control price.
- Platform readings differ: Polymarket’s Democratic probabilities were higher than Kalshi’s for both chambers in this snapshot.
- Timing matters: These figures reflect the 6:09 p.m. ET observation, rather than necessarily the prices at the update’s 6:30 PM ET publication.
Sources & attribution
- Published
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- DeFi Ratedefirate.com
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- https://defirate.com
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Full attribution under the Digital Millennium Copyright Act (DMCA), 17 U.S.C. § 512: this article is an original report by Infiniti Intelligence that summarizes the reporting of the publishers named above, links to their original work, and reproduces no protected expression beyond brief factual reference and in-line attribution (“according to DeFi Rate”). All rights in the underlying reporting remain with the publishers listed; nothing here implies endorsement by or affiliation with them. Rights holders may request correction, update or removal through the contact address published at infiniti.w3ai.io.
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