Polymarket vs Kalshi: how they actually differ in 2026
A side-by-side comparison of the two largest prediction markets — regulation, US access, contracts, fees, liquidity, and resolution rules. Honest read of where each is strong and where it isn't.
Two-sentence summary
Kalshi is the regulated US prediction market — CFTC-licensed, USD-settled, open to US residents, and strongest on economics, weather, sports, and corporate events. Polymarket is a permissionless crypto-based prediction market on Polygon, geo-blocked from US users, with deeper liquidity on headline political and global-event contracts and a broader catalog overall.
Comparison table
| Dimension | Polymarket | Kalshi |
|---|---|---|
| Regulation | Not CFTC-regulated; offshore-style operation | CFTC-regulated Designated Contract Market (DCM) |
| US user access | Geo-blocked from US IP addresses | Open to US residents |
| Settlement currency | USDC on Polygon (crypto) | USD via US bank rails |
| Account model | Self-custodied wallet, permissionless | KYC'd brokerage account |
| Market mechanism | AMM + limit-orderbook hybrid | Central limit orderbook |
| Fees | No taker fees; cost via spread | Per-contract trading fees |
| Typical strength | Politics, global events, viral topics | Economics, weather, sports, US corporate events |
| Liquidity profile | Concentrated on headline markets | Broader across regulated US-focused contracts |
| Resolution | UMA decentralized oracle | Kalshi's published settlement sources |
| API access | Public REST + GraphQL | REST API (KYC required) |
Regulation & US access
This is the headline difference. Kalshi is a CFTC-regulated Designated Contract Market (DCM), the same designation held by CME and ICE Futures. It went live in 2021 after multi-year regulatory negotiations and is the legal way for US residents to trade event contracts on a regulated US exchange.
Polymarket reached a 2022 settlement with the CFTC and now geo-blocks US IP addresses. Volume comes primarily from non-US traders. Trying to access Polymarket from a US IP without a VPN returns a blocked-region notice; US residents using Polymarket are violating its terms of service and may face account / asset risk.
If you're in the US and you want a real, enforceable account, the answer is Kalshi.
Contracts & coverage
Both exchanges list binary event contracts, but the contract sets diverge:
- Kalshi leans into US-focused, regulated-friendly verticals — Fed rate decisions, CPI prints, weather, sports outcomes, IPO timing, M&A approvals, congressional dates, and a growing politics catalog. Settlement sources are listed up-front per market.
- Polymarket is broader and faster — political nominees and elections worldwide, geopolitical conflicts, crypto price targets, celebrity events, and meme-driven contracts that wouldn't pass Kalshi's contract-design review.
If you're researching a serious macro or US-corporate-event question, Kalshi usually has the cleanest contract specification. If you're tracking a global political or attention-driven event, Polymarket usually has the deepest book.
Liquidity & fees
Volume comparisons can mislead. Polymarket prints big notional figures on headline markets — especially during US election cycles — but liquidity drops off sharply outside those headliners. Kalshi's volume is lower in aggregate but more consistently distributed across its regulated catalog, and market makers there are more active on small US-focused contracts.
On fees: Polymarket has historically charged no taker fees (cost shows up in the spread on its AMM-orderbook hybrid). Kalshi charges per-contract trading fees that vary by contract price and side. For most retail traders, spreads and depth matter more than published fees — check the orderbook on the specific contract you're trading.
Resolution rules
Kalshi publishes the settlement source for each market in the contract terms. Resolution is centrally administered against that source. Disputes are handled through Kalshi's regulated process.
Polymarket resolves through the UMA optimistic oracle — a decentralized dispute system. Most markets resolve uncontested, but contested resolutions go through UMA's voting mechanism, which has occasionally produced controversial outcomes when contract language was ambiguous.
For traders, the practical takeaway: read the contract terms before you trade. Both exchanges have had high-profile contracts where the resolution surprised the market because the rules were technically met by an unexpected outcome.
Which should you use?
- You're in the US and want a real account → Kalshi. It's the only legal option.
- You're outside the US and want maximum market coverage → Polymarket usually has more listings, especially on global political events.
- You're trading a Fed / CPI / weather / sports / US-corporate event → Kalshi, usually with better liquidity on those specific contracts.
- You're trading a 2028 election or geopolitical event → Polymarket usually has the deeper book.
- You want to compare prices across both → Many traders watch Polymarket prices as a reference even when trading the Kalshi version (or vice versa). Where the two exchanges price the same event differently, that gap is what we call "edge" at Octagon AI — and it's the foundation of our research reports.
Frequently asked questions
Is Polymarket legal in the United States?
Polymarket is not regulated by the CFTC. After a 2022 enforcement settlement, US users were officially restricted; access from US IP addresses is geo-blocked. Most Polymarket volume comes from outside the US. Kalshi, by contrast, is a CFTC-regulated Designated Contract Market (DCM) and is the legal way for US residents to trade event contracts on a regulated exchange.
What is the main difference between Polymarket and Kalshi?
Polymarket is a permissionless, crypto-based prediction market built on Polygon using USDC. Kalshi is a CFTC-regulated US exchange that settles in USD via traditional banking. Kalshi is open to US residents; Polymarket geo-blocks them. Polymarket typically lists more event categories (including politics and global topics) but operates outside US regulation.
Which has better liquidity, Polymarket or Kalshi?
It depends on the contract. Polymarket has historically dominated headline political and global-event markets in raw notional volume, especially during US election cycles. Kalshi has deeper, more consistent liquidity on its regulated US-focused contracts — economics, weather, sports, and corporate events — where its market makers are most active.
How do fees compare on Polymarket vs Kalshi?
Polymarket has historically charged no taker fees and uses an AMM-style liquidity pool, so the cost shows up as spread. Kalshi charges per-contract trading fees, with the exact rate dependent on contract price and side. For most retail traders the practical cost difference is small; spreads and contract-specific liquidity usually matter more than published fees.
Can I use both Polymarket and Kalshi?
Non-US traders can use both. US residents are blocked from Polymarket and should use Kalshi. Some sophisticated traders use Polymarket prices as additional information when trading the corresponding Kalshi contract, since the two exchanges sometimes price the same event differently — that gap is what Octagon AI calls 'edge' and surfaces in its research.
Research both with Octagon AI
Octagon publishes AI research reports on every active Kalshi prediction market — model probability versus live price, cited drivers, refreshed continuously. Polymarket coverage is on the roadmap.
