Kalshi vs Polymarket: The Complete 2026 Comparison

Last updated: May 26, 2026

As of May 2026, Kalshi and Polymarket are both CFTC-regulated US prediction-market exchanges — but they cost different money, list different markets, and pay you different things for holding cash between trades. Here’s exactly which one fits your trading style — sourced from CFTC filings, each platform’s published fee tables, and current US monthly volume figures.

Kalshi vs Polymarket in one sentence: Kalshi is the CFTC-regulated US-dollar exchange you pick for cleaner regulation, ACH funding, and ~3.50% APY on idle cash; Polymarket is the world’s largest prediction market by liquidity (~$9B/month) and the better fit for global, political, and crypto-native traders post its $112M QCEX acquisition.

If you’re choosing between the two biggest names in US prediction markets, you’ve landed in the right place. Kalshi has been CFTC-regulated since 2021. Polymarket spent years in regulatory limbo before its $112M acquisition of QCEX in late 2025 unlocked US trading for everyone. As of 2026, both platforms are open to most US residents — but they are very different products.

This Kalshi vs Polymarket guide compares the two on the things that actually matter: fees, liquidity, markets, regulation, payments, state availability, sports contracts, and the kinds of trades each is best suited for. We pulled real numbers from CFTC filings, both platforms’ own fee docs, and current US monthly volume — currently around $9B/month on Polymarket out of roughly $21B in total US prediction market volume across the category.

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Trading event contracts involves risk of loss. US residents only. Terms apply.

TL;DR: Kalshi vs Polymarket at a Glance

	Kalshi	Polymarket
Current welcome offer	Terms vary — see live offer at sign-up	Terms vary — see live offer at sign-up
Regulator	CFTC-regulated DCM since Nov 2020; live since June 2021	CFTC-regulated DCM via QCEX acquisition ($112M, Dec 2025)
Geographic access	All 50 US states + DC (state challenges ongoing in NV, MA)	Most US states; restrictions vary, partner sources list AZ, IL, MA, MD, MI, MT, NV, OH as currently unavailable
Fees	Variable tier; ~$0.01–$0.02 per contract, capped at peaks (see fee table below)	Dynamic taker fees: peak 0.75% Sports, 1.00% Finance/Politics/Tech, up to 1.80% Crypto. Maker rebate 0.20%
Funding	ACH, debit, wire — US dollars, immediate first-deposit funding up to $250	USDC on Polygon (native), plus Apple Pay, Google Pay, ACH, debit, wire via QCEX/US app
Monthly volume (2026)	Growing, multi-billion (≈$44B Open Interest figures reported by Binance Research)	~$9B/month trading volume; ~$56B notional volume cited in industry reports
Best for	Traders who want CFTC certainty, US-dollar simplicity, deep economic + political markets	Traders who want global liquidity, the widest market menu, and crypto-native settlement
Our rating	4.4 / 5	4.5 / 5

Quick verdict: If you’ve never used a prediction market and you want it to feel like a normal US brokerage, start with Kalshi. If you want the deepest order books, the most exotic markets, and you already understand stablecoins, start with Polymarket. Many serious traders use both — and that’s where arbitrage gets interesting.

Open my Kalshi account → ACH funded · Earn ~3.50% APY on idle cash.

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Trading event contracts involves risk of loss. US residents only. Any welcome offer terms vary.

For the full single-platform deep dives, see our Kalshi breakdown and the Polymarket safety guide.

Welcome offers compared: how Kalshi and Polymarket sign-up credits work

Before we dig into the platforms, here’s how each side’s welcome program actually works — terms vary, so the specific offer you see is whatever is live at your click.

Polymarket welcome offer

Polymarket’s welcome offer is distributed through its media-partner program; specific code values rotate, so the exact bonus you’ll see depends on the partner code surfaced at your sign-up. Bellwether links directly to Polymarket’s current public sign-up flow — the offer you’ll see is whatever is live as of your click. Eligibility is US 18+, US residential address in a supported state, KYC.

Polymarket also runs a separate native referral program for users who hit lifetime-volume thresholds on their own account. That program pays a percentage of fees from direct and indirect referrals for a window after each new signup. It’s the more lucrative path long-term — but it’s gated behind your own trading history.

For first-time users, the public sign-up flow (via partner links like Bellwether) is the realistic on-ramp because it doesn’t require the lifetime-volume gate.

Kalshi welcome offer

Kalshi runs an active welcome program distributed through its referral system. Current bonus terms vary; sign up via Bellwether’s link to see the live offer. Eligibility is US-only, 18+, KYC required. Trading credit (where issued) is not withdrawable; profits from it generally are.

Kalshi does not run an open affiliate program in the Polymarket sense — referrals come from existing users, and any media-partner deals are individually negotiated.

Real talk: if your goal is to actually understand prediction markets quickly, the dollar size of any welcome offer shouldn’t be the deciding factor. The platform that fits how you think about markets matters more.

Understanding Prediction Markets (before you weigh Kalshi vs Polymarket)

Prediction markets are exchanges where traders buy and sell binary contracts tied to real-world outcomes. Each contract pays $1 if the predicted event happens, and $0 if it doesn’t. The current price between $0.00 and $1.00 reflects the market’s collective probability for that outcome.

If a contract for “Will the Fed cut rates in December 2026?” is trading at $0.62, the market is implying a 62% chance of a rate cut. If you buy 100 “Yes” contracts at that price, your cost is $62 and your maximum payout is $100. If the Fed cuts, you profit $38. If it doesn’t, you lose your $62.

This structure is what makes prediction markets a distinct asset class from sportsbooks, options, and traditional binary options:

Two-sided: every trade has a counterparty trader, not a house running a vig
Standardized: every contract settles at $1 or $0, no spread games
Transparent: order books are public; prices update continuously
Continuous: you can exit a position anytime there’s liquidity, you don’t have to wait for the event to resolve

That continuous exit ability is the part new users underestimate. If you buy “Yes” at $0.30 and news pushes the price to $0.55, you can sell to lock in the gain — same as selling a stock that’s gone up. You’re not stuck holding until the event resolves.

The category has gone mainstream fast. The New York Times, Wall Street Journal, USA Today, and Nieman Lab now cover prediction markets as a standalone news beat, citing market-implied odds the way they used to cite Vegas lines or analyst consensus. Total US monthly trading volume across the category is roughly $21 billion as of 2026.

For first-time users, our guide to how event contracts work covers the basics in one read.

The CFTC’s Role

Both Kalshi and Polymarket are now regulated by the Commodity Futures Trading Commission (CFTC) — the federal agency that oversees US derivatives markets, including futures, swaps, and event contracts.

The CFTC’s jurisdiction matters for three reasons:

Federal preemption. Once the CFTC designates a platform as a Designated Contract Market (DCM), most state-level gambling laws don’t apply, because the CFTC classifies event contracts as swaps, not bets. This is the legal hook both platforms rely on to operate across state lines.
Anti-fraud / anti-manipulation rules. DCMs must enforce position limits, prevent market manipulation, and provide audit trails. That’s what separates a CFTC-regulated event contract from an offshore prediction site.
Customer fund protection. DCMs are required to segregate customer funds. Your trading balance isn’t supposed to be commingled with operating capital.

In early 2026 the CFTC reaffirmed that prediction-market event contracts fall under its exclusive federal jurisdiction. That preemption doctrine is being tested in Nevada and Massachusetts, where state regulators have challenged Kalshi’s sports contracts in particular. The cases are ongoing and worth watching if you live in those states.

Polymarket’s History With the CFTC

Polymarket has the more colorful regulatory story.

Founded in 2020 by Shayne Coplan, Polymarket launched as a decentralized prediction market built on the Polygon blockchain, settled in USDC. It quickly became the dominant global venue for political prediction markets, including the 2020 and 2024 US presidential elections — where it routinely beat traditional pollsters on accuracy.

The problem: Polymarket wasn’t registered with the CFTC. In January 2022 the CFTC fined the company $1.4 million and ordered it to wind down all non-compliant markets for US users. For nearly four years afterward, Polymarket technically blocked US-based traders, though many continued to access it through VPNs (something Polymarket’s terms of service prohibited).

That changed in December 2025. Polymarket acquired QCEX (QC Exchange LLC) — a small, CFTC-licensed Designated Contract Market — in a deal reported at $112 million. The acquisition gave Polymarket immediate, legitimate CFTC-regulated infrastructure to relaunch in the United States. QCEX now operates as “Polymarket US,” and the CFTC officially lists it as a designated contract market.

The relaunch came with two big changes for US users:

Fiat funding now works. You don’t have to bridge USDC manually. Apple Pay, Google Pay, ACH, debit card, and wire all work through the US app
KYC is mandatory. Polymarket’s global product is more pseudonymous; the US version requires standard identity verification

The state-by-state picture is still evolving. Most partner pages currently list Polymarket US as unavailable in AZ, IL, MA, MD, MI, MT, NV, OH — though California has been a particular flashpoint and the legal landscape there is moving. Check Polymarket’s own state-availability page before you fund the account.

For a step-by-step walkthrough, read our guide to Polymarket’s US-relaunch details; if you’re trading from California specifically, see our Polymarket in California breakdown.

Kalshi’s Regulatory Journey

Kalshi was born CFTC-regulated, which is the simplest way to describe the difference.

Founded in 2018 by MIT graduates Tarek Mansour and Luana Lopes Lara, Kalshi spent two years working with the CFTC before launching. In November 2020 the agency approved Kalshi as a Designated Contract Market (DCM) — the first ever DCM dedicated exclusively to event contracts. The exchange officially went live in June 2021. Sequoia Capital led a $30 million Series A in February 2021, with Charles Schwab, Henry Kravis, SV Angel, and Y Combinator Continuity also participating.

The early Kalshi product was deliberately wonky: inflation prints, jobless claims, Fed decisions, GDP numbers. The bet was that institutional traders and macro nerds would form a credible base before mainstream markets arrived. It worked.

Two later expansions defined Kalshi’s modern shape:

Election contracts (2024). After a landmark federal court ruling, Kalshi became the first US platform legally allowed to offer election-outcome contracts. The 2024 presidential cycle was when Kalshi’s volume genuinely scaled.
Sports event contracts (2024–2025). Kalshi rolled out contracts on NFL games, college football outcomes, NBA Finals matchups, and golf majors. This expansion is the one drawing state-regulator pushback — particularly from Nevada gaming regulators and the Massachusetts AG — because it looks economically similar to sports betting. Kalshi’s defense rests on federal preemption: as a CFTC-regulated swap, sports event contracts fall outside state gambling law.

As of 2026, Kalshi operates in all 50 US states + DC. Some partner pages cite an “unavailable” list reflecting individual platform decisions or state-specific litigation, but the company’s official position is nationwide availability.

For a deeper look at fees, custody, and complaints data, see Kalshi’s CFTC posture explained.

Pros and Cons: Kalshi vs Polymarket scorecard

Kalshi

Pros	Cons
CFTC-regulated DCM since launch — the cleanest US legal story	Smaller global liquidity than Polymarket on marquee markets
Funded in US dollars; ACH and debit work the way you expect	Fee structure looks complex on first read (variable per-contract)
Earn ~3.50% APY on cash and open positions (as of early 2026)	Customer support is email-only
Wide market selection: economics, politics, climate, sports, culture, tech	Heavily oriented toward US events; less global news exposure
Immediate funding — up to $150 on first ACH deposit, up to $250 thereafter	App store reviews are strong, but Trustpilot reviews skew critical on withdrawals
Strong mobile app (4.7★ on iOS, 4.4★ on Google Play)	Sports contracts face active state-level legal challenges

Polymarket

Pros	Cons
Largest prediction-market liquidity in the world — ~$9B/month volume	Newer US regulatory footing (Dec 2025 via QCEX)
Most diverse market menu globally — politics, geopolitics, crypto, culture, AI, science	State availability still evolving; not yet everywhere
Order books are deeper on marquee events (especially political)	USDC-on-Polygon adds a learning curve for non-crypto users (though US app abstracts most of it)
Multi-outcome markets and ranged outcomes, not just binary Yes/No	Higher peak fees than Kalshi on some categories (up to 1.80% on Crypto)
Apple Pay + Google Pay + ACH funding in the US app	Brand still carries past association with the 2022 CFTC fine
Strong international community and continuous global news coverage	No interest-on-cash equivalent to Kalshi’s 3.50% APY

Markets and Trading Options: Kalshi vs Polymarket on listings depth

Both platforms run binary “Yes/No” contracts that settle at $1 or $0. The differences are in what they list, how much depth each market has, and whether the contracts are vetted by a regulator before going live.

What Kalshi lists

Kalshi groups its markets into more than ten formal categories. Active categories as of mid-2026:

Economics — CPI, PCE, jobless claims, GDP, Fed rate decisions
Politics — election outcomes, Congressional control, individual race odds (2026 Midterms)
Sports — NFL game outcomes, college football, MLB, NBA Finals, golf majors, NCAA tournaments
Crypto — Bitcoin price ranges, Ethereum price ranges, ETF flows
Climate / Weather — high temperatures, hurricane counts, snowfall
Culture — Oscar winners, box office milestones, music chart positions
Tech & Science — product launches, AI benchmark milestones, space missions
Health — disease counts, FDA approvals
Financials / Companies — earnings beats, stock price levels, indexes
World — geopolitical events with measurable resolution

Every Kalshi market is reviewed and approved by the CFTC before going live. That’s the trade-off: slower listing pace, but every contract has a clearly defined resolution source written into the rulebook.

What Polymarket lists

Polymarket’s market menu is wider and faster-moving, partly because Polymarket’s global product doesn’t require pre-approval for every listing. Categories trading actively as of 2026:

Politics — global elections, geopolitical decisions, US 2026 Midterms, 2028 Presidential
Sports — NFL, NBA, college sports, soccer, F1, tennis, MMA, growing US sports coverage in the US app
Crypto — BTC/ETH price targets, regulatory decisions, exchange events, on-chain milestones
Geopolitics — wars, treaties, sanctions, leadership changes
Pop culture — celebrity events, awards, viral moments
Tech / AI — product release dates, AI model benchmark scores, company milestones
Climate / Weather — disaster counts, temperature records
Science — research breakthroughs, space launches

Polymarket’s multi-outcome markets are a structural advantage. Instead of forcing every question into a Yes/No frame, Polymarket can list a single market with 10+ named outcomes (think: “Who wins the 2028 Republican nomination?” with one row per candidate). Kalshi tends to split those into multiple binary contracts.

Volume snapshot

According to industry reporting (Binance Research / industry trackers) in 2026:

Metric	Polymarket	Kalshi
Notional volume (lifetime headline)	~$56B	~$44B
2026 monthly trading volume	~$9B / month	Several billion / month, lower than Polymarket
Largest single-market depth	Marquee elections: $100M+ open interest	Macro / sports: order books in the millions per event

Polymarket genuinely has more liquidity in absolute terms. Kalshi catches up only on US-specific markets where its regulatory clarity attracts US institutional flow.

For a category-specific breakdown, see our pick for the best platforms for election markets.

User Interface and Experience

Both platforms ship a web product and a mobile app. The feel is meaningfully different.

Kalshi UX

Kalshi reads like a brokerage app. Clean white background, market cards with implied probability shown both as a percentage and a price, an order book on the side, and a familiar deposit/withdraw section that looks like Robinhood or Schwab. Reddit feedback is mostly positive on the interface itself — common praise calls out the clean charts and the “feels normal” sign-up flow. Common complaints: occasional bugs on the iOS app and slow email-only customer support.

The mobile app rates 4.7 stars on the Apple App Store (34,000+ reviews) and 4.4 on Google Play (5,820 reviews) as of early 2026.

What it gets right: – Markets are grouped logically – Yes/No prices are displayed prominently — you don’t have to learn a new mental model – ACH and debit deposits are first-class citizens, not bolt-ons

What’s awkward: – The fee preview on order tickets is technically accurate but takes a moment to read (the variable structure isn’t intuitive) – “Open positions earn interest” is great, but it’s not surfaced clearly in the main UI

Polymarket UX

Polymarket’s web product feels more like a crypto exchange — dark mode by default, dense market cards, multiple bid/ask levels visible, and a comment section under each market where traders argue about news in real time. That comment culture is part of the appeal; it’s also where the platform genuinely outclasses Kalshi.

The US mobile app is newer (post-QCEX relaunch) and is currently more sports-focused than the global web product. Expect that to expand as the US listing pipeline matures.

Reddit feedback on Polymarket consistently praises liquidity and the comment community as the killer features. Common complaints: USDC-on-Polygon learning curve for non-crypto users on the global product (mostly abstracted away in the US app), and confusing fee math at certain price points.

The bottom line on UX: Kalshi feels familiar. Polymarket feels powerful. Pick the one that matches how you think.

We dig deeper into iOS vs Android vs web on our Polymarket app review.

Trading Fees and Market Depth: Kalshi vs Polymarket on cost

This is the section where the two platforms diverge most.

Kalshi fees

Kalshi charges a variable per-contract fee calculated from the contract’s implied probability and maximum payout. The result is a curve: fees are tiny at extreme prices (deep “Yes” or deep “No”) and peak in the middle around $0.50.

A simplified version of the Kalshi fee schedule (as published in early 2026, via Finder.com):

Contract price	Fee per contract	Fee per 100 contracts
$0.01	$0.01	$0.07
$0.10	$0.01	$0.63
$0.25	$0.02	$1.32
$0.50	$0.02	$1.75 (peak)
$0.75	$0.02	$1.32
$0.90	$0.01	$0.63
$0.99	$0.01	$0.07

Translation: a $100 trade at fair value costs you roughly $1.75 in fees. On extreme-priced contracts it can drop to 7 cents.

Other Kalshi fee facts worth knowing: – No membership fee – No ACH deposit or withdrawal fees – 2% fee on debit card deposits and withdrawals – Interest of ~3.50% APY paid on cash + open positions (effectively an offset to trading fees)

The interest yield is genuinely unusual. If you keep $5,000 in Kalshi long-term, you’re earning roughly $175/year just sitting on the balance, which more than offsets the fees most retail traders pay.

Polymarket fees

Polymarket’s published fee schedule is structurally different. It’s a dynamic taker-fee model that peaks at the 50-cent mark (mirror image of Kalshi’s curve), with different category caps. Effective March 30, 2026, Polymarket lists peak effective taker rates of:

Category	Peak effective taker fee
Sports	0.75%
Finance	1.00%
Politics	1.00%
Tech	1.00%
Crypto	1.80% (highest)

Polymarket US separately publishes a 0.30% taker fee and a 0.20% maker rebate schedule for its US designated-contract-market product. That means market makers (limit-order providers) get paid 20 basis points for adding liquidity — the opposite of paying a fee. Active traders who specialize in providing liquidity on Polymarket can run effectively-negative fee structures.

Many older Polymarket markets, particularly long-tail political markets, have no fees at all — a relic of the original launch promise. Don’t assume all Polymarket markets are fee-free; the dynamic-fee model now covers most actively-marketed markets.

Net fee verdict

For a typical US retail trader buying $100 of a marquee market at fair value: – Kalshi: ~$1.75 in fees + earn 3.50% APY on balance – Polymarket (Sports): ~$0.75 in fees at peak – Polymarket (Crypto): ~$1.80 in fees at peak

On pure trade-cost, Polymarket is cheaper on sports and politics, more expensive on crypto. Kalshi’s hidden edge is the interest yield. If you’re going to hold significant balance idle between trades, Kalshi’s 3.50% APY meaningfully changes the all-in math.

For the full per-contract math at every price point, see our breakdown of Kalshi’s fee structure.

Liquidity and Volume

Liquidity is the single biggest reason serious traders prefer one venue over another. Tight bid-ask spreads = lower slippage = better fills.

Metric	Polymarket	Kalshi
2026 monthly trading volume	~$9 billion	Several billion (lower)
Top single-market open interest	$100M+ on marquee election markets	Tens of millions on top events
Order-book depth on Top 20 markets	Generally deeper	Comparable on US-only macro / sports
Typical bid-ask spread on liquid market	1–2 cents	1–3 cents

The numbers aren’t perfectly apples-to-apples (different reporting cadences and methodologies), but the broad pattern holds: Polymarket is the global liquidity leader, while Kalshi is competitive or better on US-specific macro and political markets where US institutional flow concentrates.

For most retail-sized trades — say, under $1,000 per ticket — you won’t notice the difference on top-100 markets on either platform. The difference shows up on: – Large positions ($10K+) – Long-tail markets – Late-stage markets near resolution where liquidity often thins

Polymarket also has a maker rebate structure that incentivizes market-making, which keeps spreads tight on actively-listed markets. Kalshi pays out a liquidity incentive program to market makers as well, but the structure is more discretionary.

Payment Methods Compared

Method	Kalshi	Polymarket US
ACH (US bank transfer)	Yes — instant up to $150 first deposit, up to $250 subsequently	Yes
Debit card	Yes — 2% fee	Yes
Wire transfer	Yes	Yes
Apple Pay	Limited	Yes
Google Pay	Limited	Yes
USDC (Polygon)	No	Native
Other crypto	No	Via on-ramps
Withdrawals to bank	Yes — ACH (free), debit (2%)	Yes via QCEX rails; USDC withdrawals on global product

Bottom line on payments:

Kalshi = traditional US fiat workflow. If you’ve ever funded a brokerage account, this is identical.
Polymarket US = both worlds. Fiat on-ramps via QCEX integration and the native USDC stack for users who already hold stablecoins.

If you already use crypto, Polymarket’s USDC option is the cheapest, fastest funding method available on either platform. If you don’t, ACH on Kalshi is the least friction.

For walkthroughs, see how to deposit on Polymarket and our USDC on Polygon funding guide.

State Availability

This is the area changing fastest in 2026. Always check both platforms’ own state-availability pages before depositing.

Kalshi state availability

Kalshi officially operates in all 50 US states + DC. The CFTC’s federal preemption doctrine is the legal basis. There are active state-level challenges in:

Nevada — Gaming Control Board challenging sports event contracts
Massachusetts — AG action targeting sports contracts
New Jersey — DGE issued cease-and-desist on certain sports contracts (Kalshi continues operating pending federal court ruling)

These cases will likely shape the legal landscape into 2027. For now, Kalshi keeps trading nationwide pending appellate review.

Polymarket US state availability

Polymarket’s US relaunch via QCEX is still rolling out state by state. Industry partner pages currently list Polymarket US as unavailable in AZ, IL, MA, MD, MI, MT, NV, OH. California has been a particular point of attention because of state regulator interest in event contracts. This list will change — check polymarket.com directly before depositing.

Quick lookup

State	Kalshi	Polymarket US
California	Available (pending state action review)	Restricted / changing — verify
Texas	Available	Available
Florida	Available	Available
New York	Available	Available
Illinois	Available (sports under review)	Not currently available
Nevada	Sports contracts contested, other markets available	Not currently available
Massachusetts	Sports contracts contested	Not currently available
Arizona	Available	Not currently available
Ohio	Available	Not currently available

Full state guides: California · Texas · Florida · New York.

Hottest Markets Right Now (May 2026)

A snapshot of the kind of markets each platform is currently moving real volume on. By the time you read this, names will have rotated — treat the categories, not the individual lines, as the takeaway.

On Polymarket (highest open interest): – 2028 US Presidential election — early-line markets on nominees and final outcomes already showing 9-figure cumulative volume – 2026 Midterms — control of the House and Senate — large open interest as the cycle warms – Bitcoin price by year-end 2026 — multiple range markets actively traded – AI benchmark milestones — “Will GPT-class model X cross benchmark Y by date Z?” – Russia-Ukraine resolution markets — long-running, deep liquidity – AI replacement of jobs by 2030 — multi-year geopolitical/economic markets

On Kalshi (most active categories): – Fed rate decisions — every FOMC meeting drives a major liquidity spike – CPI / inflation prints — monthly cycle, predictable trader engagement – 2026 NCAA Basketball Championship — and ongoing NFL playoff markets – NBA Finals matchup contracts — both team-specific and series-outcome – GTA 6 launch-price market — culture markets driving retail flow – 2028 Presidential election early markets — growing volume alongside Polymarket – Hurricane season counts — climate markets that resolve in late 2026

The pattern: Kalshi dominates US-specific macro and event markets where institutional traders want CFTC-regulated venues. Polymarket dominates global, geopolitical, and crypto markets where international participation matters.

See our category picks for best platforms for election markets and best platforms for sports event contracts.

Arbitrage Opportunities Between Kalshi and Polymarket

When the same underlying event trades on both platforms at different prices, an arbitrage exists.

A simple example: suppose the 2028 Presidential winner market lists Candidate A at: – Kalshi: “Yes” at $0.55 – Polymarket: “Yes” at $0.51

A trader could buy “Yes” on Polymarket at $0.51 and sell “Yes” on Kalshi at $0.55, locking in a $0.04 spread per contract (minus fees on both sides). Multiplied across thousands of contracts, this is a real edge.

In practice, Kalshi vs Polymarket arbitrage has a few quirks:

Funding friction. You need balance on both platforms. Moving funds between them takes time and incurs fees.
Contract specification differences. A “2028 winner” market on Kalshi and Polymarket may have subtly different resolution criteria — the candidate-eligibility wording, the inclusion of write-in candidates, the close-out date. Read both rulebooks before assuming the markets are identical.
Fee asymmetry. Polymarket’s Sports/Politics taker fee (1.00% peak) plus Kalshi’s variable fee can eat a $0.04 spread quickly.
Liquidity depth. A spread that looks free on the screen may not absorb a real-money position.
State availability. If one of the two contracts isn’t available in your state, you can’t arb it.

Despite all this, cross-platform arbitrage is one of the most consistent edges in US prediction markets for traders willing to set up the plumbing. Many serious traders maintain accounts on Kalshi, Polymarket, and Robinhood Event Contracts specifically for this reason.

See if Robinhood Event Contracts fits as my third leg → For arbitrage between Kalshi, Polymarket, and Robinhood.

Read the Robinhood Event Contracts breakdown →

Trading event contracts involves risk of loss. US residents only.

Many cross-platform arbitrageurs also maintain a third account; see our Robinhood Event Contracts breakdown for the third leg of the stack.

Sports Betting Comparison: Kalshi vs Polymarket on event contracts

Both platforms now offer sports event contracts — but the products feel different.

Kalshi sports

Kalshi rolled out sports contracts in 2024 and aggressively expanded in 2025. As of 2026, Kalshi offers contracts on: – NFL game winners and totals – College football outcomes – MLB outcomes – NBA game and series outcomes – Golf major winners – NCAA tournament outcomes – Boxing, MMA, tennis (limited)

The contracts settle binary (Yes/No team-X-wins) and behave like simple moneyline bets in payoff structure. The legal framing is critical: Kalshi positions these as federally regulated event contracts, not sportsbook bets. State gaming regulators (especially in NV, MA, NJ) disagree, and the litigation is active.

Polymarket sports

Polymarket’s global product has long offered sports markets, but the US app is currently more sports-focused than the global web product as the US rollout matures. Active US sports coverage in the app: – NFL (game outcomes and futures) – NBA (game outcomes, series, season-long) – College football and basketball – Soccer / international competitions – Tennis and golf majors

Polymarket’s sports markets often have deeper international liquidity on global events (World Cup, Olympics, Champions League) where Kalshi’s US-only user base limits depth.

Sports verdict

For US-only sports (NFL, NBA, NCAA): Kalshi has the more mature listing pipeline. For global sports and international competitions: Polymarket has deeper books. Both will keep iterating fast through the 2026 NFL season.

If your goal is “I want to bet on the Sunday games,” check both. Spreads and totals will be close, but small price differences add up over a season.

For our category pick, see best platforms for sports event contracts.

Which Platform Fits You?

A simple Kalshi vs Polymarket decision framework:

You should start with Kalshi if:

You’re new to prediction markets and want it to feel like a brokerage app
You prefer US dollars and ACH funding
You want to earn ~3.50% APY on idle balance
You’re focused on US macro, US politics, or US sports
CFTC-regulated-since-day-one matters to you
You’re in a state where Polymarket US isn’t yet available

Open my Kalshi account + earn ~3.50% APY on idle cash →

Sign up via Bellwether’s link →

Trading event contracts involves risk of loss. US residents only.

You should start with Polymarket if:

You want the deepest order books on big global events
You want exposure to international markets and geopolitics
You’re comfortable with crypto or want the option to use USDC
You’re chasing the highest-volume political and election markets in the world
You like the comment-community side of prediction markets
You’re in a state where Polymarket US is currently available

Open my Polymarket account → Sign up via Bellwether’s link · See the current live welcome offer at sign-up.

Sign up via Bellwether’s link →

Trading event contracts involves risk of loss. US residents only.

You should start with Robinhood Event Contracts if:

You already use Robinhood and want event contracts inside an existing brokerage
You want very simple, retail-scale exposure to a smaller curated set of events
Lower stakes, lower friction, fewer markets — that’s a feature for you

Our Robinhood Event Contracts breakdown covers the trade-offs.

The “use both” answer

Most serious prediction-market traders use at least two platforms. The reasons:

Different markets list on different venues. You want optionality
Arbitrage requires positions on multiple sides
Liquidity isn’t always best on the same venue every day
State-availability quirks mean one platform may be temporarily restricted in your state

If your time and capital allow, opening accounts on both Kalshi and Polymarket — plus Robinhood Event Contracts as a backup — gives you the broadest, most resilient access to the US prediction-market landscape.

Ready to move?

You’ve seen the depth. If you’ve decided, here’s the shortest path to a funded account:

Polymarket route: Sign up via Bellwether’s link →
Kalshi route (easiest US flow): Sign up via Bellwether’s link →
Robinhood Event Contracts route (if you already use Robinhood): See the current Robinhood offer →
Want to stack all three? Read the bonus stack guide — current welcome offers vary by platform.

By Avery Chen · Markets Editor, Bellwether · Last updated: May 27, 2026 — we update this page when regulators issue new guidance, fees change, or new platforms launch.

Frequently Asked Questions

What are prediction markets?

Prediction markets are exchanges where users buy and sell binary contracts tied to real-world outcomes. Each contract pays $1 if the predicted event happens and $0 if it doesn’t. The price between $0.00 and $1.00 reflects the implied market probability. Examples: “Will the Fed cut rates in December 2026?”, “Will the Chiefs win the Super Bowl?”, “Will Bitcoin hit $200K by year-end?”

Is Kalshi legal in the US?

Yes. Kalshi has been a CFTC-regulated Designated Contract Market (DCM) since November 2020, with public trading since June 2021. It operates in all 50 US states + DC. State-level legal challenges to specific contract categories (especially sports) are ongoing in Nevada, Massachusetts, and New Jersey, but the platform continues to operate nationwide under federal preemption.

Can US users access Polymarket in 2026?

Yes — through Polymarket US, the CFTC-regulated entity formed when Polymarket acquired QCEX in December 2025 for $112 million. Polymarket US is a designated contract market and is currently available to eligible US residents in most states. Industry partner pages currently list it as unavailable in AZ, IL, MA, MD, MI, MT, NV, and OH; the list is changing as the US rollout progresses. Always check polymarket.com directly before depositing.

What are event contracts?

Event contracts are financial derivatives whose payout depends on whether a specific future event happens. The CFTC classifies them as swaps under US federal law, which is why CFTC-regulated platforms like Kalshi and Polymarket US can offer them across state lines under federal preemption. Each contract settles at $1 (yes) or $0 (no).

How does Polymarket use blockchain?

Polymarket’s global product runs on Polygon — an Ethereum-compatible blockchain — and settles trades in USDC, a US-dollar stablecoin. Smart contracts handle settlement transparently and automatically. The US version of Polymarket (post-QCEX) uses the same underlying smart-contract infrastructure for settlement, but layers on KYC, fiat funding via Apple Pay / Google Pay / ACH, and a US-app interface that abstracts most of the crypto complexity. You can use Polymarket US without ever touching USDC directly if you prefer.

Are prediction markets gambling?

This is a contested legal question. Under US federal law (CFTC jurisdiction), event contracts are swaps, not bets — a legal classification that gives federally-regulated platforms the right to operate nationwide. State gaming regulators in Nevada, Massachusetts, New Jersey, and others have argued that some categories (especially sports event contracts) are economically equivalent to gambling and should be regulated as such. The federal-vs-state question is being litigated. Functionally, prediction-market trading shares characteristics with both: it involves risk of loss and uncertain outcomes (like gambling), but it operates as a two-sided exchange with continuous pricing and no house edge (like a financial market). For your own purposes, treat it as risk capital regardless of the legal label.

Which has better liquidity?

Polymarket has more overall liquidity — roughly $9 billion in monthly trading volume as of 2026, with notional volume cited at $56B+ in industry reporting. Its order books are deeper on marquee global events. Kalshi is competitive or stronger on US-specific markets — particularly US macro releases (CPI, Fed decisions) and US politics — where US institutional flow concentrates. For most retail trades under $1,000, liquidity is sufficient on both.

Which has lower fees?

It depends on category. Polymarket is cheaper on Sports (peak 0.75%) and competitive on Politics/Finance/Tech (peak 1.00%). Polymarket Crypto markets carry the highest peak fee at 1.80%. Kalshi’s per-contract variable fee tops out around 2% effective on the middle of the probability curve, but Kalshi pays ~3.50% APY on cash and open positions — meaningfully offsetting fees for any trader who holds significant balance. For active small-ticket traders, Polymarket Sports is the cheapest. For traders who park capital between trades, Kalshi’s interest yield can come out ahead.

Can I arbitrage between Kalshi and Polymarket?

Yes, this is one of the most consistent edges in the US prediction-market ecosystem. When the same underlying market lists at different prices on each platform, you can buy on the cheaper side and sell on the more expensive side, locking in the spread. Caveats: fees on both legs eat a lot of the apparent spread, contract-resolution wording can differ subtly between platforms, and you need funded accounts on both. Cross-platform arbitrage works best for traders willing to monitor multiple venues and tolerate funding-cycle friction.

Are there state restrictions?

Kalshi: officially operates in all 50 states + DC. State-level legal challenges to sports event contracts are active in NV, MA, and NJ but the platform continues operating pending appellate review. Polymarket US: currently restricted in AZ, IL, MA, MD, MI, MT, NV, OH (according to industry partner pages), with California status changing. Both lists are evolving in 2026 — always check the platform’s own state-availability page before funding an account.

Which has better sports markets?

For US sports (NFL, NBA, NCAA, MLB, golf): Kalshi has the more mature listing pipeline and offers consistent contracts on game outcomes, series matchups, and futures. For international sports (soccer, tennis, World Cup, Olympics): Polymarket has deeper books because its global user base trades these markets continuously. The US Polymarket app has expanded sports coverage rapidly and will likely close the gap on US sports through the 2026 NFL season.

What’s the minimum deposit?

Kalshi: $0 minimum on most accounts; ACH instant funding works up to $150 on first deposit and up to $250 on subsequent deposits. Polymarket US: there’s no formal published minimum on the US app for fiat funding via Apple Pay / Google Pay / debit / ACH. Any welcome-offer deposit threshold varies — the value you’ll see depends on Polymarket’s current public sign-up flow.

Verdict — Both Win in Their Lanes

Don’t believe anyone who tells you one of these platforms is the clear winner. Kalshi and Polymarket are now both legitimate, CFTC-regulated, US-accessible prediction-market exchanges — and they’re built around different bets about what users want.

Kalshi wins if you want a US-dollar brokerage feel, federally-regulated-from-day-one credibility, the 3.50% APY on cash, and a clean entry point into US macro, politics, and sports markets.

Polymarket wins if you want the deepest global liquidity, the widest market menu, multi-outcome contracts, crypto-native settlement options, and the most actively-traded political markets in the world.

The most interesting answer for many serious traders is both. Open both accounts, use each for what it’s best at, and watch for arbitrage where the same market lists at different prices across platforms.

Trading event contracts involves real risk of loss. Whatever you put in, treat it as risk capital — money you can afford to lose. The platforms have improved dramatically over the past 18 months, but the underlying activity is still speculative.

Open my Polymarket account → Sign up via Bellwether’s link · See live welcome offer at sign-up.

Sign up via Bellwether’s link →

Trading event contracts involves risk of loss. US residents only.

Open my Kalshi account + earn ~3.50% APY on idle cash →

Sign up via Bellwether’s link →

Trading event contracts involves risk of loss. US residents only.

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Keep reading: our Kalshi breakdown · Polymarket’s fee structure · Robinhood Event Contracts review · the basics of prediction markets · Polymarket’s US-relaunch details · best for election markets · best for sports event contracts · California guide.

Next: Kalshi review — fees, custody, and complaints in depth