2026 US Primary Election Predictions & Odds

Texas kicked off the 2026 midterm primary season on March 3 with $1.1M in Kalshi volume on the Senate races alone, far outpacing Polymarket’s $80K on the same market. James Talarico took the Democratic nomination, and the Republican side heads to a runoff after John Cornyn and Ken Paxton both fell short of 50%.

The general election betting market is already moving with a full slate of primaries ahead. DeFi Rate will be tracking these with live prediction odds aggregated from Kalshi and Polymarket, updated every 30 minutes.

This is our central hub, giving you a view of the featured markets, key states we are tracking, props and where to bet on the primaries and midterms.

Featured markets (House + Senate control)

The Kalshi House seat count forecast has dropped from ~212 in November to 203.3 in March — a 9-seat shift toward Democrats in four months. The “below 193” bracket sits at 28%, meaning nearly 1-in-3 odds that Democrats flip the House with a meaningful majority. That trend line hasn’t shown much sign of leveling off — nine months of data and no meaningful recovery yet.

2026 races we’re tracking across prediction markets

Not every competitive race has meaningful market liquidity yet. The states below were selected based on Kalshi volume, general election competitiveness, and governor or downballot market depth.

How to bet on 2026 midterm markets

Most people start with the headline markets — Senate control, House control — and stop there. That’s fine, but it leaves a lot on the table.

Prediction markets for the 2026 cycle cover far more ground than just picking a winner. Both Kalshi and Polymarket, have roughly 150 distinct contracts live right now, grouped below by type. You will also find the winner markets on PredictIt. The markets are legally open to all 50 states. Each category works differently, carries different liquidity levels, and serves a different purpose depending on what view you want to express.

Every election contract is structured the same way: a Yes/No binary priced between $0.01 and $0.99. That price represents the market’s implied probability on a win. A contract at $0.67 means the market collectively gives a 67% chance that outcome will be the winner. If the outcome occurs, the contract settles at $1.00. If it doesn’t, it settles at $0.

Sell your shares before election day

A benefit to prediction markets is that you can exit any position before resolution by selling your contracts at the current market price. Say you bought 100 shares of Cornyn YES early in the night at 60¢ ($60.00), before the results started rolling in — as votes came in strongly in his favor and the market repriced him up to 81¢, you could sell for $81.00 and lock in a $21.00 profit without waiting for the race to be called.

The inverse is just as useful: if you’d bought Paxton YES at 20¢ ($20.00) and watched his odds collapse to 10¢ as Cornyn pulled ahead, selling early recovers $10.00 rather than holding to resolution and losing the full $20.00.

Senate primary markets

The Texas Democratic primary alone drew roughly $4.8M in volume before resolving on March 3 — arguably one of the highest-volume individual primary markets in US history. That’s what Senate primary markets look like at full liquidity. These markets ask who will win a party’s Senate nomination in a given state, with one contract per candidate priced individually. Other high-liquidity Senate primary markets currently live include the Georgia Republican primary (May 19), the Maine Democratic primary (June 9), and the Michigan Democratic primary (August 4).

Available on: Kalshi and Polymarket.

Governor primary markets

The Florida Republican governor primary is the largest non-Texas governor market in the cycle at roughly $2M, with Georgia, Iowa, and Maine active behind it. Governor primary markets follow the same structure as Senate primaries but tend to move on different signals — endorsements and candidate exits carry more weight at the gubernatorial level than polling does. Worth monitoring closely in the days around major announcements.

Available on: Kalshi and Polymarket.

House primary markets

Most individual House primary contracts are currently trading under $50K in volume, which means spreads tend to be wider and prices can be less reliable than Senate or governor markets. House primary markets cover congressional district-level nominee races — TX-23, TX-33, NC-04, NY-12 — and the liquidity picture tends to change fast. The volume on these markets picks up significantly in the weeks before each primary date, concentrated in races that generate national press: competitive open seats, incumbent challenges, or districts with heavy party investment. Worth monitoring if you follow specific districts closely, but approach with a liquidity caveat in mind.

Available on: Kalshi and Polymarket.

Election props

Election props are a broad category of supplementary markets that go beyond the binary winner question. These include margin of victory brackets, turnout thresholds, county-level outcome markets, and specific matchup combos. Texas has the deepest prop market ecosystem in the cycle by a wide margin so far — Texas props alone account for roughly $30M in volume, dwarfing every other state. As the cycle progresses and more primaries resolve, expect prop markets to expand into other high-attention states. These are best suited for traders who have a specific view on how an outcome will play out, not just who wins.

Available primarily on: Kalshi.

Meta and combo markets

There are only two Senate primaries combo markets on Kalshi right now, but they’re among the more interesting bets in the cycle. Both ask a version of the same question: will the dominant party hold its Senate nominations cleanly, or does at least one state produce an upset?

The Democratic combo covers six states — Texas, Illinois, Iowa, Maine, Michigan, and Minnesota — and resolves Yes if at least 5 of the 6 Dem candidates win their primaries. It’s trading at Yes 67% / No 33% as of March 6. Talarico’s Texas win is already locked in, so traders effectively need 4 of the remaining 5. The Republican combo tells a different story: Yes 19% / No 81%, reflecting how much more volatile GOP primary fields have been this cycle.

One thing to flag before trading either: the combo structure means a single unexpected result can flip your entire position. Read the resolution rules carefully — particularly how the platforms handle late-resolving primaries.

Available on: Kalshi, Polymarket.

Downballot markets

Downballot markets cover Attorney General, Lieutenant Governor, Secretary of State, and Comptroller races. They exist on both platforms but carry thin liquidity — most contracts trade under $10K. The audience is narrow: traders who follow state-level politics closely or want exposure to a specific officeholder’s prospects. These markets don’t tend to see significant volume growth unless a particular race breaks into national news. Available on Kalshi and Polymarket, but approach with the same liquidity caution as House primaries.

Available on: Kalshi, Polymarket

General election markets

These are November winner markets — who wins the Senate seat in Georgia, who wins the governor’s race in Iowa — and they are distinct from primary markets. A general election market opens the moment the relevant primary resolves and closes on November 3. Holding a position in the primary market does not give you exposure to the general; the two are separate contracts. General election markets currently live for most major Senate and governor races are listed in the race-by-race section above. These tend to be the most stable markets in terms of price movement until primaries resolve and the November matchups become clear.

Available on: Kalshi, Polymarket, and PredictIt.

Where to bet on 2026 primaries and midterms

The three platforms below cover different parts of the market. Which one makes sense depends on what you’re trying to trade.

Kalshi primary markets

Kalshi is a CFTC-regulated exchange carrying the deepest liquidity on US election markets. For the 2026 cycle, Kalshi has individual Senate, House, and governor race markets across all competitive states, plus primary advance and seat count bracket markets not available elsewhere. You will also find prop markets and we expect that mention markets may unfold down the road. All contracts are cash-settled in USD, and Kalshi is available in all 50 states.

New users get a $10 bonus using the Kalshi promo code DEFI.

Polymarket primary markets

Polymarket carries the widest selection of midterm markets by count, including the balance of power combo market and primary advance contracts on several races. The volume on Polymarket’s 2026 midterm markets is growing fast, with the House control market alone showing $3.6M traded (International, not US). Polymarket received DCM status from the CFTC in November 2025 and can be funded with USDC, card, or bank transfer. Polymarket US has a backlog of customers waiting to get in.

You can join via our Polymarket promo code page and use the invite code TWITTER to try and bypass the backlog.

PredictIt primary markets

PredictIt covers Senate and governor general election winner markets using a share-based model with a $3,500 cap per contract. It does not offer primary advance, party composition, or seat count markets. PredictIt continues to operate under a CFTC no-action letter allowing limited political event markets for academic research purposes. Its parent company Aristotle received CFTC approval on January 26, 2026 for AristotleExchange.com as a DCM and DCO, though that has yet to change how PredictIt itself operates. PredictIt is best suited for those who want exposure to general election outcomes with a lower position limit.

Review of PredictIt coming soon!

Key dates to watch

We expect the volume on most markets to increase in the week before primary dates on the election calendar. This is due to increased interest in polling, endorsements, and early voting data starting to come in. General election markets often trade before primaries resolve, typically structured around which party will win the seat. But once nominees are confirmed, trading shifts toward the specific November matchup and volume typically increases as the race becomes clearer.

Is betting on Senate primaries legal in the US?

Yes. Trading on Senate primaries and general elections is legal on prediction markets. Kalshi, designated by the CFTC as a Designated Contract Market, offers election contracts as regulated financial instruments under the Commodity Exchange Act — not gambling. A 2024 federal district court ruling confirmed that election contracts do not constitute “gaming” under the CEA. The CFTC initially appealed and then dropped the appeal in May 2025 under new leadership, cementing federal legality. There are currently a dozen companies seeking CFTC approval for prediction markets. You can see the full list of prediction apps here.

Texas Senate primary is an example of what’s coming

The March 3 Texas Senate primary was the first major test of the 2026 cycle and offered a case study in how prediction markets can sometimes move faster and more accurately than polling. Heading into primary day, Kalshi traders had James Talarico at 86% to win the Democratic nomination while polls showed the race considerably tighter. Talarico won. On the Republican side, traders priced a runoff between Paxton and Cornyn as the most likely outcome before a single vote was counted. The Texas Senate primary markets drew over $5M in volume on the Democratic side alone, making it one of the highest-volume individual primary markets in US history to that point.

How to bet on US primaries and midterms

If you’re new to primary markets specifically, the mechanics are worth understanding before you put money in. Depending on the platform and the race, you can bet on who wins a nomination, whether a candidate advances past a primary, the margin of victory, turnout by party, or even which counties a candidate will carry. The most liquid markets are nominee markets and general election winner markets, but the full range of options is worth knowing before you place a position.

Every primary market on Kalshi and Polymarket is structured as a Yes/No contract on a specific outcome. You are not picking a winner from a list — you are deciding whether a particular outcome will happen and buying a position accordingly.

How to buy and sell election contracts

Each outcome has its own contract priced between $0.01 and $0.99. That price reflects the implied probability that the outcome will occur — a contract trading at $0.72 means the market collectively gives that outcome a 72% chance of happening.

If the outcome occurs, the contract settles at $1.00 and you collect the difference. If it does not, it settles at $0 and you lose your stake.

You can also sell your position at any point before the market closes, locking in a gain or cutting a loss without waiting for the result.

How to read the odds using the Texas GOP as an example

Take the Texas GOP runoff market currently on Kalshi. The question is: who wins the Republican Senate nomination, Paxton or Cornyn? Paxton’s contract is priced at $0.55 — the market gives him a 55% chance of winning the runoff on May 26. Buy 100 contracts at that price and you’re in for $55. Win and you collect $100; lose and you’re out your stake. Cornyn’s contract sits at $0.45, the mirror image. The two sides do not sum to exactly $1.00 because Kalshi charges a small fee on winning positions, typically between 1% and 4%.

Primary vs. general election markets

Primary markets resolve the moment the relevant primary or runoff result is certified. General election markets remain open through November 3. The two markets are distinct — winning a primary does not settle the general election market. Traders who want exposure to the full cycle need to hold or trade both