Bettors Back Democrats in $100 Billion Prediction Market

Online prediction markets have positioned themselves as a real-time indicator of voter sentiment in the upcoming midterm elections.

Bettors placed wagers on the outcomes of races across the country on Monday, the day before the general election. The aggregated data from major platforms suggests a strong expectation for a Democratic performance. Polymarket, a leading online exchange, listed the probability of a total Democratic victory at 74 percent. This scenario requires the party to gain control of both the United States House of Representatives and the United States Senate.

The same platform assigned a 23 percent chance to a split outcome. In that specific case, Democrats would take the House while Republicans retain control of the Senate. The odds of a Republican sweep of both chambers stood at 6 percent. A scenario in which Republicans won the House but lost the Senate carried a 2 percent probability.

Kalshi, a competing prediction market, displayed similar figures early on Monday afternoon. The site showed a 74 percent likelihood of the Senate leaning Democratic. It indicated a 94 percent chance that the House of Representatives would be considered safe for Democratic candidates. These figures reflect the consensus of users trading contracts on the platforms.

Individual Senate races showed consistent trends across both exchanges. In Maine, Democratic candidate Troy Jackson was favored to unseat Republican Senator Susan Collins. Polymarket gave Jackson a 73 percent chance of winning the seat. Kalshi listed his victory odds at 72 percent as of Monday afternoon.

In Michigan, Democratic nominee Abdul El-Sayed held a 78 percent probability of defeating Republican Mike Rogers. Both prediction markets assigned the same odds to this race. This likelihood persisted despite recent endorsement activity by Representative Haley Stevens. Stevens, who had been El-Sayed's rival in the Democratic primary, publicly supported Rogers.

Texas and Ohio also showed strong Democratic advantages in the prediction markets. Democrat James Talarico had a 74 to 75 percent chance of winning the Senate seat against Republican Ken Paxton. In Ohio, Democrat Sherrod Brown was listed with a 71 percent chance of reclaiming his former Senate seat from Republican Jon Husted. These odds were consistent across the Kalshi and Polymarket websites.

Financial experts noted that the surge in political betting raises questions about how the Internal Revenue Service will treat winnings. Andrew Gordon, a tax attorney and accountant, outlined the potential tax implications for users on the social media platform X. Gordon stated that the IRS has not yet clarified how these specific contracts are taxed. He warned that the final classification could alter a taxpayer's bill by thousands of dollars.

Gordon identified three main possible tax treatments for these contracts. The first is classification as gambling, where winnings are treated as ordinary income. Under this rule, taxpayers could deduct only 90 percent of their losses, and only if they itemize deductions. The second option is treatment as capital gains, allowing losses to offset gains and up to $3,000 of other income. The third is classification as Section 1256 contracts, which splits income between long-term and short-term rates regardless of holding period. Gordon used a hypothetical example to illustrate the difference, noting that a break-even year could still result in a tax liability if treated as gambling.