2026 Midterm Election Odds: The Best Value Prediction Markets

The tumultuous second term of US President Donald Trump is fast approaching another milestone, with the 2026 midterms scheduled for Tuesday, November 3rd.

Trump’s Republican party is braced for a tough set of elections this autumn, with the President’s current approval rating having hit a record low of 34%. Historically red states like Texas are also facing unusually close elections, prompting the Republicans to schedule an unprecedented midterm convention in Dallas.

Trump’s bombastic approach continues to polarize voters, too, while driving significant midterm trading volumes on Polymarket. Here, you can buy and sell headline outcomes like the results of governor elections in individual states, while making high-profile referendum picks.

We’ll take a closer look at the most traded markets below! We’ll also address the best value trades at the time of writing.

Our exclusive Polymarket bonus code is CORG and will get you $20 after you sign up and deposit $10. If you’re looking for more options to trade on The Midterms, check out our list of the best political betting sites.

Odds on Control of the Senate and the House

The November midterms will ultimately reshape the composition of the US Senate and House, right up until the next national election in November, 2028. This will have a huge bearing on the remainder of Donald Trump’s term in office, especially with regards to the President’s ability to pass his polarizing legislative agenda.

The Republicans are also burdened by the weight of history, with the incumbent party having historically lost ground and seats in both chambers. We’re unlikely to see this trend reversed in 2026, but there are different ways in which you can trade the Senate and House races!

“Democrats to Win the Senate in 2026” | “Yes” at 51¢ | 50% Chance

Previously, traders on Polymarket narrowly favored the Republicans to retain control of the Senate, with this outcome carrying an implied probability of 55% as recently as August 2nd.

The party currently maintains a majority of 53 seats to 47, while it continues to benefit from a structurally advantageous electoral map.

However, trading “Yes” on the Republicans at this price offered minimal upside and relatively low liquidity. The implied probability of the Republicans retaining the Senate has also fallen steadily since October 26th, 2025, when it peaked at 75%.

This trend has continued, with the Democrats now afforded a 50% chance of winning the Senate. Sustained polling has also shown the party building a consistent national lead of between five and six points since early June, while they continue to perform strongly in so-called “swing” states and even some Republican strongholds.

Rising inflation caused by the ongoing Iran war also remains a key factor ahead of the midterms. Although this cooled slightly to 3.4% in July, it remains well above the 2% target and is likely to rise further after a recent ceasefire failed.

The Democrats have risen steadily in this market, from a low of 24% on October 25th, 2025. However, there’s still scope for the price to increase further, and trading “Yes” on a Democrat win in this market offers optimal value. This could even create opportunities to sell in September or October.

 “The Balance of Power – A Democrat Sweep” | “Yes” at 46¢ | 47% Chance

Another reason to back the Democrats in the Senate race is that Polymarket’s “Balance of Power” market now affords them a 47% probability of winning both chambers. 

This suggests that the actual probability of them winning the Senate alone is higher than currently implied. It certainly reaffirms the idea that this particular outcome is noticeably underpriced at present.

But should you trade “Yes” on the Democrats sweeping both chambers? This is highly recommended if you’re confident that they’ll win the Senate race, as they have an 88% probability of flipping the House. They need just five seats to achieve this aim and retain a marked funding advantage in key swing states.

So, consider buying “Yes” shares in this market at their current price of 46¢. Although a Democrat sweep is far from guaranteed, this market also has a strong potential upside and may create potential opportunities to sell for a profit. The price has increased incrementally since June 15th.

Did you know?

Did you know?

Our exclusive Polymarket promo code, CORG, will earn you a $20 trading bonus when you sign up to Polymarket and make a $10 deposit.

Referendum Issues and Individual Senate Races: Trading Other Top Markets

The midterms also allow states to propose referendums on key policy decisions. Voters can then have their say, while traders on Polymarket can speculate on how the highest-profile votes will go.

You can even trade on the outcome of individual governor and Senate races, with some highly volatile and others offering excellent long-term value. Here are a couple of alternative midterm markets to keep your eye on this year.

“Billionaire One-Time Wealth Tax to Pass in California” | “Yes” at 26¢ | 26% Chance

Californians are likely to vote on the introduction of a one-time wealth tax this autumn, which will be applied to billionaires in the state. This is a highly controversial piece of legislation, while trading “Yes” on it being voted in unlocks a current probability of just 26%.

The bill continues to face strong bipartisan opposition, with the state’s Democratic Governor Gavin Newsom aiming to defeat a proposal that he believes would significantly diminish the local authority’s tax base. 

The state’s super-rich have also established the so-called “California Business Roundtable” war chest. This has currently raised over $213 million in total, and is being used to fund an aggressive anti-tax media campaign.

However, buying a “Yes” contract isn’t dependent on whether or not the bill actually passes. This investment can still offer value if you believe the current price of 26¢ will rise in the late summer and early autumn, which is a possibility if inflation remains high and nationwide economic anxiety persists.

With entrenched grassroots support and core Democratic backing for stronger wealth distribution measures, trading “Yes” here is a smart short-term pick. Remember, “Yes” shares have seen their price peak as high as 61¢ since the market opened, and this has the potential to increase again.

“Susan Collins (Republican) to Win the Maine Senate Race” | “Yes” at 30¢ | 30% Chance

The Maine Senate race has been incredibly dramatic, starting with the withdrawal of Democratic primary winner Graham Platner amid ongoing sexual assault allegations.

On the Republican side, incumbent Susan Collins faced a significant backlash after a fatal Immigration and Customs Enforcement (ICE) shooting during a traffic stop in Biddeford. She subsequently clashed with Trump in attempting to manage the fallout, too, eroding different segments of her base.

Overall, this has seen Collins’ “Yes” price fall from 50¢ when the market opened to just 30¢ at the time of writing. The Democrats’ decision to swap out Platner for Troy Jackson has also stabilized their campaign, with the latter known as a progressive who has deep rural ties and appeal. 

However, Collins remains immensely popular with voters on an individual level, while the 73-year-old is also well-funded. What’s more, she retains a relatively strong moderate base and broad appeal among centrists, in a state where Republicans have largely dominated the Senate race since the 1970s. Collins herself has won the seat five times since 1996.

Recent polling by Fox News has placed her just two points behind in the race and within the margin of error, too, suggesting she may have a much greater chance of winning than her current odds imply. So, buying “Yes” on Collins to win at just 30¢ offers considerable long-term value, potentially creating a window of opportunity to sell for a profit in late summer or early autumn.

The Last Word – Trading the Midterms With Polymarket

While there are a number of midterm prediction markets that offer minimal value or upside, there are others that remain underpriced and capable of delivering a profit over the next few months.

Backing the Democrats to flip the Senate offers a relevant case in point. While this remains a relatively tall order, the true probability of them achieving this aim is probably higher than the 48% currently implied.

Trading “Yes” on both the California wealth tax passing and Susan Collins being re-elected in the Maine Senate are also underpriced at present. So, buying up shares now leaves you well-placed to sell and lock in a profit in the buildup to the midterms.

Just remember to track your picks daily and follow the relevant news cycles. You can buy and sell shares anytime before your chosen market settles with Polymarket, creating much-needed flexibility as prices continue to fluctuate.

Do you want to make any of these trades? Use our exclusive CORG promo code on Polymarket to earn a $20 trading bonus when you register and deposit $10.