2026 Midterm Election Odds: The Best Value Prediction Markets

The tumultuous second term of US President Donald Trump is fast approaching another milestone, with Americans now heading to the polls ahead of the 2026 midterms.

Trump’s Republican party is braced for a tough set of election results. The President’s current approval rating hovers around 32%, while it’s as low as 26% when it comes to his handling of the economy. Historically red states like Texas and Maine are also increasingly likely to be flipped, 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.

With some 65% of U.S. adults now also blaming Trump’s policies for a persistently high cost of living, the midterms may see the President pay a significant price for his ongoing war on Iran.

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 78¢ | 78% 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 78% chance of winning the Senate (up by 14 percentage points since October 21st). Sustained polling has also shown the party building a consistent national lead of between six and nine points at least 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 3.7% 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 50% in less than two months, so you could sell now or hold until settlement later this week. However, the Republicans retain a slight structural advantage overall, so selling now may be optimal (liquidity permitting).

“The Balance of Power – A Democrat Sweep” | “Yes” at 77¢ | 77% Chance

Another reason to back the Democrats in the Senate race is that Polymarket’s “Balance of Power” market now also affords them a 77% 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 95% 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 sizable profit if possible. You can also hold until settlement, with a Democrat sweep looking increasingly likely given the prevailing economic climate, rising oil prices, and Trump’s flailing ratings. Much will depend on your appetite for risk.

Buying “Yes” now may also offer value if you intend to hold until the contract resolves. However, this unlocks minimal upside, too, while the return doesn’t justify the potential risk of loss.

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.

“Billionaire One-Time Wealth Tax to Pass in California” | “Yes” at 24¢ | 24% Chance

Californians will 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 24% (down from 30% just one month 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.

Of course, buying a “Yes” contract isn’t necessarily dependent on whether or not the bill actually passes. However, there’s now minimal time and liquidity left in the market, which makes it incredibly difficult to buy and flip shares prior to settlement. So, you should only invest at the current price of 23¢ if you believe that the market will settle “Yes”.

Overall, the price has increased from a low of 17¢ on June 15th. If you bought in at this price, you could attempt to sell now and yield an ROI of 35.29% (if you’re able to locate a buyer). Otherwise, hold until settlement and hope that grassroots activists and the powerful SEIU United Healthcare Workers West union are able to carry the vote in their favor.

“Susan Collins (Republican) to Win the Maine Senate Race” | “Yes” at 27¢ | 27% 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.

The race has fluctuated in recent weeks, but recent polls afford Jackson a lead of between two and nine points. Some of the larger polls see Collins trail but within the margin of error, so her actual win probability may be higher than her current “Yes” price implies. Collins also has a record of over-performing in the Pine Tree State.

So, if you bought shares in Collins at 30¢, you may want to hold your position rather than attempt to sell for a nominal loss. Avoid buying “Yes” shares now, however, as this represents a straight bet on Collins being re-elected in the Senate.

The Last Word – Trading the Midterms With Polymarket

With US voters now heading to the polls, the results of the 2026 midterms are now just hours away. This means that your focus should switch from buying shares to managing your existing positions and attempting to maximize profit (or minimize loss).

How you manage your trades depends on their individual circumstances and your appetite for risk. For example, I’d recommend holding your “Yes” shares in Susan Collins if you bought in at 30¢ or higher, while you can attempt to sell your position if you backed the Democrats to win the Senate.

You can also attempt to flip your position if you previously traded the Democrats to win both the Senate and the House. Once again, your choice will depend on the price at which you bought “Yes” and the prevailing levels of liquidity in the market.

Just remember to track your picks and follow the relevant news cycles as the election results are revealed. This will help you to make more informed decisions and safeguard your capital effectively.

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