Polymarket vs Kalshi for the 2026 Midterms: Which Platform Has Better Election Markets?

The 2026 midterm elections are six months out, and prediction market traders are already deep in. Polymarket and Kalshi both list dozens of midterm contracts — House control, Senate control, individual races in battleground states, even down-ballot questions about specific candidates. They’re the two serious options if you want to bet on what happens in November, and the choice between them isn’t obvious.

Both platforms have working sign-up offers right now. Polymarket gives a $50 bonus on a $20 deposit with codes BOOST20 or SKENS — you put in $20, get $50 credit on top, end up with $70 to trade with. Kalshi gives $10 after $10 in trades with GRINDERS or COVERS. The answer for most readers is probably “claim both,” but which one to use for serious midterm trading is a different question — and the platforms have meaningfully different strengths.

This guide compares them on the factors that actually matter for election betting: market depth, liquidity, fees, available races, regulatory status, and which sign-up offer is more valuable for an election-focused trader.

Quick verdict

For US residents who want to bet on midterm elections legally and have only one account, Kalshi is the safer pick — it’s CFTC-regulated, available in all 50 states, and accepts USD bank transfers. Its midterm markets are deep enough that liquidity isn’t a problem on the big questions like House and Senate control.

For traders who want the deepest liquidity, the widest variety of midterm contracts (including hyper-specific markets that Kalshi doesn’t list), and don’t mind funding with crypto, Polymarket is the stronger platform. The catch: it’s not available in nine US states, and you’ll need USDC to deposit.

For most readers, the optimal move is signing up to both. Put $20 into Polymarket with BOOST20 or SKENS (you get $50 bonus on top), and pick up Kalshi’s $10 after $10 in trades. That’s a $20 deposit converting to $80 of trading credit across both platforms.

Market depth and variety

This is where the platforms differ most. Both list the big midterm markets (House control, Senate control), but the depth of secondary markets is dramatically different.

Polymarket’s midterm coverage includes the headline races plus a deep bench of niche markets: individual Senate races in Pennsylvania, Ohio, Arizona, Georgia, Nevada, Michigan, Wisconsin, and North Carolina; House control by margin (will Republicans hold by more than 10 seats, etc.); specific candidate questions like “Will Bernie Moreno hold his Ohio Senate seat?”; turnout markets; and aggregate margin markets that ask about national vote share.

The “Republicans Sweep” and “Democrats Sweep” outright winner markets each typically carry seven-figure volume. The individual Senate race markets are deep enough to trade meaningful size without moving the price significantly.

Kalshi’s midterm coverage is narrower but professionally curated. The main contracts are House majority winner, Senate majority winner, and individual state-by-state Senate and gubernatorial races in competitive states. There are fewer hyper-specific markets — you’ll find “Republicans hold the Senate” but probably not “Republicans hold the Senate by 4+ seats” the way you would on Polymarket.

That said, Kalshi’s markets are easier to navigate for newcomers. There’s less noise, the contracts have clearer resolution criteria written in plainer English, and the platform has done work to standardize how each race resolves. For a casual midterm bettor who just wants to take a position on the major outcomes, Kalshi’s curation is a feature, not a limitation.

Winner: Polymarket for serious traders. Kalshi for newcomers who want a clean experience.

Liquidity

Liquidity matters because illiquid markets have wide spreads — you pay the difference between the bid and ask every time you enter or exit a position. On a market with a 4-cent spread, you start every trade 4% behind. On a market with a 0.5-cent spread, that drag is negligible.

Polymarket’s flagship midterm markets (“Republicans Sweep,” “House Control 2026,” “Senate Control 2026”) run with 1-cent spreads or tighter for most of the day. Volume on the top markets exceeds $50M cumulative since the 2024 cycle ended. You can buy or sell $5,000+ positions in the major markets without moving the price meaningfully.

Kalshi’s flagship midterm markets have improved dramatically since their 2024 expansion. The House and Senate majority markets routinely show 1-2 cent spreads with enough depth that retail-sized positions ($100-$5,000) execute cleanly. But the deeper you go into individual races, the wider the spreads get.

For a trader putting on a $1,000 position in a state-specific Senate race, Polymarket will typically give you a better price. For a trader putting on a $100 position in the House majority winner, the platforms are roughly equivalent.

Winner: Polymarket on individual race markets. Roughly tied on the headline national markets.

Fees

This is more nuanced than it looks because both platforms have hidden costs beyond their stated fee structures.

Polymarket charges no maker fees and small taker fees (currently 0-2% depending on the market). Maker orders (limit orders that don’t immediately fill) often pay rebates. The hidden cost is funding — you need USDC, which means converting USD on an exchange (~0.5-1% fee depending on exchange) and bridging to Polygon. Withdrawing is the same in reverse.

Kalshi charges 1-2% per contract on most trades. The hidden cost is much smaller because deposits and withdrawals are free via ACH bank transfer.

For a trader who plans to deposit once and let the money ride until November, Polymarket’s lower trading fees probably win. For a trader who’ll be cycling money in and out frequently, Kalshi’s free bank deposits matter more.

Winner: Roughly tied. Depends on your trading style.

Regulatory status and US availability

This is the cleanest decision factor for many readers.

Kalshi is CFTC-regulated and available in all 50 US states. You can sign up from anywhere in the US, fund with USD, and use it legally without worrying about state-level restrictions. The CFTC oversight also means stronger consumer protections.

Polymarket has a US version (also CFTC-regulated) but is unavailable in nine states: Arizona, Illinois, Massachusetts, Maryland, Michigan, Montana, Nevada, New Jersey, and Ohio. Several of these are politically active states where midterm trading would be especially relevant — losing access to election markets if you live in Michigan or Ohio is a real cost.

If you live in any of the nine restricted states, this entire comparison resolves to Kalshi by default. For everyone else, regulatory status is a tie since both are CFTC-overseen.

Winner: Kalshi, decisively, for residents of the restricted states. Tied for everyone else.

Sign-up offers compared

Both platforms run referral programs that are worth claiming. The offers aren’t a primary decision factor — you should pick the platform based on the features above — but they meaningfully reduce your effective cost of entry.

Polymarket: $50 bonus on a $20 deposit with promo codes BOOST20 or SKENS during signup. You deposit $20 of your own money, the $50 bonus credits to your account, and you end up with $70 total to trade with. The bonus credits after your deposit clears and your first prediction is placed. Either code works identically. See our Polymarket promo code guide for the redemption walkthrough.

Kalshi: $10 in trading credit after you’ve placed $10 in trades using codes like GRINDERS, COVERS, GOAL, or several others. You have to trade $10 first, then the $10 credit applies. See our Kalshi promo code guide for current working codes.

The Polymarket offer is significantly larger in absolute terms. A $20 deposit turning into $70 of trading credit is a 250% return on your initial commitment — you’re effectively trading with 3.5x your deposit. Kalshi’s offer is smaller and requires the $10-in-trades hurdle before crediting, but it doesn’t require any crypto onboarding. For most readers, claiming both is the right move.

Specific midterm markets worth watching on each platform

For traders deciding where to put their first midterm position, here are the high-volume markets each platform handles well:

Best traded on Polymarket:

Republicans Sweep / Democrats Sweep (outright control of both chambers)
Individual Senate races in PA, OH, AZ, GA, NC
Margin markets (Republicans hold Senate by 2+ seats, etc.)
House control by specific seat count thresholds

Best traded on Kalshi:

House majority winner (clean binary, deep liquidity)
Senate majority winner
Governor races in competitive states
Generic ballot question markets

If you have a strong view on a state-level race, Polymarket. If you have a view on the national balance of power, Kalshi works fine and you get the regulatory peace of mind.

How to actually use both

The workflow most active midterm traders use:

Sign up to both platforms during the same session. Polymarket with BOOST20 or SKENS (deposit $20, get $50 bonus); Kalshi with GRINDERS or COVERS (claim after $10 in trades).
Fund each conservatively to start. Polymarket via USDC on Polygon (the $20 deposit qualifies for the bonus, then add more as you find positions worth taking); Kalshi via ACH bank transfer.
Compare prices for the same market on both platforms. House majority winner is listed on both. Often there’s a 1-3 cent arbitrage opportunity where the same outcome is priced differently. Even if you’re not arbitraging, knowing the spread tells you whether you’re getting a fair price.
Specialize over time. Most serious traders end up using Polymarket for individual race markets and Kalshi for the headline national markets, based on where each platform has better liquidity for the size they want to trade.

The bottom line

Both platforms work for the 2026 midterms. Neither is a bad choice. The question is which one fits your situation:

You live in AZ, IL, MA, MD, MI, MT, NJ, NV, or OH: Kalshi only. Polymarket isn’t available where you are.
You want the simplest signup and bank-funded trading: Kalshi.
You want the deepest markets and widest variety of races: Polymarket.
You’re trading serious size on individual races: Polymarket has tighter spreads.
You don’t want to deal with crypto: Kalshi.
You want the most generous sign-up offer: Polymarket — $20 deposit turns into $70 trading balance.

For the full step-by-step on claiming each offer, see our Polymarket promo code guide and Kalshi promo code guide. If you want a broader head-to-head comparison beyond just the midterms, our general Polymarket vs Kalshi comparison covers both platforms across all use cases.