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 hovering around a record low of 32%. Historically red states like Texas are also facing unusually close elections, prompting the Republicans to schedule an unprecedented midterm convention in Dallas early in September.

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 64¢ | 64% 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 64% chance of winning the Senate (up by 1.59% since October 1st). Sustained polling has also shown the party building a consistent national lead of between six and nine points since early September, 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. This increased again to 3.9% in September (up from 3.4% the previous month), and remains well above the 2% target. It’s likely to rise further, with the conflict showing no signs of abating anytime soon.

I previously recommended that you buy “Yes” shares in the Democrats in this market at 52¢. The price has since increased by 23.08% in just two weeks, so you could sell now or hold until settlement. However, there’s less upside in this market if you want to buy now and flip your position prior to the elections.

 “The Balance of Power – A Democrat Sweep” | “Yes” at 64¢ | 64% Chance

Another reason to back the Democrats in the Senate race is that Polymarket’s “Balance of Power” market now also affords them a 64% 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 potentially 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 91% probability of flipping the House. They need just five seats to achieve this aim and retain a marked funding advantage in key swing states.

Once again, those of who you bought “Yes” shares when they were priced below 50¢ could consider selling now and banking a nominal profit. You can also hold until settlement, with a Democrat sweep looking increasingly likely given the prevailing economic climate and Trump’s flailing ratings.

Buying “Yes” now may also offer value if you intend to hold until the contract resolves. However, this unlocks minimal upside, too, as the price isn’t expected to rise much higher before November. This price may have also peaked this week.

Referendum Issues and Individual Senate Races: Trading Other Top Markets

The midterms also allow states to propose referendums on key policy decisions. Voters 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 30¢ | 30% 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 30% (up from 26% just two weeks ago).

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 well 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 30¢ will rise in the early autumn, which is a possibility if inflation remains high and nationwide economic anxiety persists.

This has already increased from a low of 17¢ on June 15th, while the previous 17 days have seen the price rise further by 15.38%.

With entrenched grassroots support and core Democratic backing for stronger wealth distribution measures, however, trading “Yes” here is a potentially smart short-term pick. Remember, “Yes” shares have also 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 43¢ | 43% 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 saw Collins’ “Yes” price fall from 50¢ when the market opened to just 30¢ on September 22nd. 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.

Although earlier polling by Abacus Data revealed an eight-point lead for Jackson, this canvassed the opinion of just 327 likely voters. Larger polls put Collins just 2-3 points behind on average and within the margin of error. More recent polls afford Collins 2-3-point advantage, and this has seen her “Yes” price surge by 43.33% to 43¢.

So, if you bought shares in Collins at 30¢, you can sell now and bank an adequate return. However, the “Yes” price has the potential to move beyond 50¢ in the coming weeks, creating a window of opportunity to sell for a higher profit in mid-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 in theory, the true probability of them achieving this aim is probably higher than the 64% currently implied.

Trading “Yes” on both the California wealth tax passing and Susan Collins being re-elected in the Maine Senate remain 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.