For years the comparison was easy: Kalshi was the regulated American exchange, Polymarket was the crypto-native platform Americans were not supposed to use. That distinction has largely collapsed. Polymarket acquired a CFTC-licensed exchange in 2025 and re-entered the United States through it, so both venues now operate as CFTC-regulated designated contract markets.
If you last formed an opinion on these platforms before 2026, the thing you based it on has changed. This article covers what actually separates them now — how you fund an account, how fees are structured, what gets listed, and, most consequentially, how disputes over outcomes are settled.
Educational content only, not legal, tax, or investment advice. Availability, fees, and product rules differ by state and change frequently. Verify current terms on each platform before depositing.
The short answer
Kalshi is a US exchange that has been CFTC-regulated since 2020. You fund it with dollars from a bank account or card, you complete identity verification, and outcomes are settled against a published rulebook. It behaves like a regulated derivatives venue, and it issues tax forms accordingly.
Polymarket now exists as two related but distinct products. The global platform is the crypto-native one most people picture: USDC on Polygon, on-chain positions, outcomes resolved through the UMA optimistic oracle. Polymarket US is the newer regulated venue, reached with dollars rather than a crypto wallet.
Most active traders end up using both companies rather than choosing one, because the market catalogs do not fully overlap.
What changed: Polymarket’s US re-entry
Rather than seeking a licence from scratch, Polymarket bought one. Its 2025 acquisition of a CFTC-licensed exchange gave it a regulated path back to US customers, and a phased app rollout followed from late 2025 into 2026.
Two practical consequences matter more than the corporate mechanics.
First, “is Polymarket legal in the US” now has a different answer than it did in 2024, though availability still varies by state and remains subject to ongoing legal challenges in several of them. Both platforms are affected by this; neither has a stable, permanent map.
Second, the regulated US product is not the same as the global platform. They differ in funding, in which markets are listed, and in how outcomes are resolved. Comparisons that treat “Polymarket” as one thing tend to mislead, and this is the single most common error in the current crop of comparison articles.
Access and funding
| Kalshi | Polymarket (global) | Polymarket US | |
|---|---|---|---|
| Currency | US dollars | USDC on Polygon | US dollars |
| Funding | Bank transfer, card, payment apps | Crypto wallet or on-ramp | Bank transfer and card options |
| Identity verification | Required | Historically not required | Required |
| Tax reporting | Issues US tax forms | Self-reported | Regulated venue reporting |
| Who it suits | US traders who want a normal brokerage feel | Non-US traders and on-chain users | US traders who want Polymarket markets without crypto |
The crypto learning curve used to be Polymarket’s biggest onboarding obstacle in the US. The regulated product removes it — at the cost of the permissionless, no-KYC access that drew people to the global platform in the first place. Which of those you consider the feature depends entirely on where you live and what you value.
How fees work
Both platforms charge takers now, which is itself a change: Polymarket was famously fee-free for a long time.
The structures rhyme more than they differ. Both scale the fee with how uncertain the contract is, peaking around the 50¢ mark and shrinking as prices approach either extreme. The logic is that a contract trading at 3¢ has far less at stake per share than one trading at 50¢.
Beyond that shared shape:
- Kalshi charges a per-contract fee, deducted at execution, with limit orders that add liquidity often treated more favourably than orders that take it.
- Polymarket applies taker fees that vary by category, with some categories cheaper than others and certain world-event markets remaining fee-free. Its regulated venue has published maker rebates, meaning liquidity providers can be paid rather than charged.
- Funding costs are easy to overlook and often larger than trading fees for casual users. Card deposits and withdrawals can carry charges on either platform.
Specific rates change often enough that quoting them in a blog post is a disservice — several widely shared comparison articles already carry numbers that are months out of date. Check each platform’s official fee page before you size anything.
The more useful point: for most retail-sized trades, the bid-ask spread costs you more than the fee schedule does. A one-cent spread on a 50¢ contract is a 2% round-trip cost, which dwarfs the posted fee on either venue. Optimising for the headline fee while ignoring liquidity is the wrong trade-off. Polymarket Odds Explained works through that arithmetic.
Market catalogs
Kalshi’s catalog is built around US event contracts — economics, politics, weather, and a sports business that expanded sharply after its 2025 launch of sports contracts.
Polymarket’s global catalog is broader and faster-moving, listing questions around culture, crypto, geopolitics, and news cycles that a regulated US venue would be slower to touch. Its US catalog is narrower than its global one.
The practical implication: if there is a specific question you want exposure to, catalog coverage decides the venue for you long before fees do. This is also why serious traders keep accounts on both — not for arbitrage, but for reach.
How outcomes get resolved
This is the most underrated difference, and the one most likely to cost you money on a position you were right about.
Kalshi settles against an exchange rulebook. Each contract has published specifications, and the exchange determines settlement. The mechanism is familiar to anyone who has traded regulated derivatives, and the accountability sits with a regulated entity.
Polymarket’s global platform settles through the UMA optimistic oracle. An outcome is proposed with a bond, a roughly two-hour challenge window opens, and a contested result escalates to a vote by UMA token holders. Once finalised on-chain the result is immutable, and Polymarket is non-custodial — it cannot simply reverse it.
That design is transparent and censorship-resistant, and it has genuinely misfired on ambiguous questions. Both of the disputes people cite most often involved contracts whose wording had no mechanical answer. If you trade the global platform, understanding this process is not optional:
- Polymarket Resolution Rules: The UMA Optimistic Oracle Explained covers bonds, timers, and the four verdicts a dispute can produce.
- Polymarket Resolution History shows how to look up how any market actually settled.
Neither model is strictly better. A rulebook gives you a clear accountable party and less drama; an oracle gives you transparency and no ability for a company to quietly change its mind. They fail in different ways, and you should know which failure you are exposed to.
Can you arbitrage between them?
Occasionally, and less often than it looks.
When similar questions are listed on both venues, prices do diverge. Before treating that as free money, check three things. Resolution criteria are rarely identical — a Yes on one platform may require something a Yes on the other does not, which means you are not actually hedged. Capital sits in two places, in different currencies, with different withdrawal timelines. And fees and spreads on both legs frequently exceed the gap you spotted.
Price disagreement between platforms is a good research prompt. It is usually telling you the contracts differ, not that one venue is wrong.
Which should you use?
Choose Kalshi if you are a US trader who wants dollar funding, straightforward tax paperwork, and settlement by a regulated exchange against a published rulebook, and if its catalog covers your questions.
Choose Polymarket’s global platform if you are outside the US or specifically want on-chain, permissionless access and the widest catalog, and you are comfortable with oracle-based resolution.
Choose Polymarket US if you want Polymarket’s markets with dollar funding and no crypto wallet.
Use both if you trade actively. The catalogs differ enough that venue loyalty costs you opportunities.
Monitoring Polymarket activity
If Polymarket is where you actually trade, the harder problem is not choosing a platform — it is noticing things in time. Prices move on news, large wallets take positions before crowds react, and disputed markets can flip while you are asleep.
Polymarket Alerts sends push notifications for price thresholds, whale trades above an amount you set, and activity from specific wallets or usernames you follow, plus a timeline of resolved markets and a section for tracking disputes. The Features page walks through each alert type with screenshots.
It monitors Polymarket rather than Kalshi, which is a deliberate focus: the on-chain transparency of the global platform is what makes wallet-level and whale-level alerting possible in the first place.
Frequently asked questions
Is Polymarket legal in the US now? Polymarket re-entered the US through its 2025 acquisition of a CFTC-licensed exchange, so a regulated US product exists. Availability still varies by state and is subject to ongoing legal challenges, so check current status for your location.
Is Kalshi or Polymarket cheaper? It depends on the market and your order type, and published rates change often. For typical retail trades the bid-ask spread usually costs more than the fee on either venue, so liquidity in your specific market matters more than the fee schedule.
Do I need crypto to use Polymarket? Not for the regulated US product, which is dollar-funded. The global platform runs on USDC on Polygon.
Which has more markets? Polymarket’s global catalog is broader and lists new questions faster. Kalshi’s catalog is focused on US event contracts, with a large sports business since 2025.
Can I bet on sports on both? Both list sports event contracts, though the specific contracts and availability differ. These are event contracts on a regulated exchange, not sportsbook wagers — see Prediction Markets vs Sportsbooks for why the distinction matters.
Does Polymarket report to the IRS? The regulated US venue operates under US reporting requirements. Activity on the global crypto-native platform is self-reported. Talk to a tax professional about your situation.
Related reading
- What Is Polymarket? — the beginner explainer.
- Prediction Markets vs Sportsbooks — why event contracts are not bets.
- Polymarket Resolution Rules — how the oracle decides outcomes.
- Polymarket Odds Explained — reading prices as probabilities.
Bottom line
The old shorthand — regulated Kalshi versus crypto Polymarket — stopped being accurate in 2026. Both are CFTC-regulated exchanges now, and the real differences sit in catalog breadth, funding mechanics, and how a contested outcome gets settled. Kalshi gives you a rulebook and an accountable exchange. Polymarket’s global platform gives you reach, on-chain transparency, and an oracle that occasionally produces results people hate. Pick based on where you live and what you want to trade, and if you are active, keep both.
Last reviewed August 2026. Prediction markets change quickly — verify fees, state availability, and product terms on each platform’s official site. Spot something out of date? Tell us on Telegram.