Chapter 17 of 33
The Short Version
As of April 2026, Polymarket and Kalshi are the two dominant prediction-market platforms. Together they have traded more than $60 billion year-to-date. They are not really competitors in the traditional sense -- they win in different categories, serve different geographies, and answer to different regulators. Polymarket dominates politics, crypto, and geopolitics; Kalshi dominates sports. Polymarket offers zero fees on politics and maker rebates on everything; Kalshi offers 1099 tax forms and easy US bank deposits. The right answer for you depends on what you trade and where you live.
This guide gives you a side-by-side breakdown of every decision factor: fees, volume, liquidity, resolution mechanism, regulation, access, and deposit methods. At the end, a decision table tells you exactly which platform to start with based on your profile, and why serious traders often end up using both.
What you'll learn in this guide
- The 2026 state-of-the-market: volumes, valuations, market share
- A detailed 14-row comparison table
- How fees actually stack up in practice (with worked trade examples)
- Who wins each major category: politics, crypto, sports, geopolitics, weather
- Resolution: UMA Oracle vs Kalshi internal team -- and why it matters
- The 2026 regulatory landscape: CFTC rulings, state pushback, congressional bills
- The five other prediction-market platforms worth knowing about
- Eight of the most common comparison questions, answered
YTD 2026: Kalshi ~$37.5B, Polymarket ~$29.2B. Weekly volumes are close; category mix is what separates them.
Part 1: The Headline Comparison
| Feature | Polymarket | Kalshi |
|---|---|---|
| Founded | 2020 (Shayne Coplan) | 2021 (CFTC-approved DCM) |
| Valuation (2026) | ~$15B latest round | ~$22B (March 2026) |
| Weekly volume | ~$2.1B (47% share) | ~$2.7B (53% share) |
| Regulatory status | CFTC via QCEX acquisition ($112M, Dec 2025) | CFTC DCM since 2020 |
| US access | Invite-only waitlist (~1M queued) | Live in 40+ states |
| International | Globally open via crypto wallet | 140-country rollout (uneven in practice) |
| Settlement currency | USDC on Polygon + new pUSD (Apr 2026) | USD in US bank accounts |
| Deposit methods | USDC (crypto onramps: MoonPay, Coinbase, direct) | ACH, wire, debit card, Apple Pay, USDC |
| Maker fees | 0% + rebates (~20-25% of taker fee) | ~75% less than taker fees |
| Taker fees | 0% politics/econ, 0.75% sports, 1.25% econ specials, 1.80% crypto | Variable, generally under 2% ($100 trade caps at ~$1.74) |
| Strongest markets | Politics, crypto, geopolitics | Sports (85-90% of volume) |
| Typical spread | 2-5 cents (tighter on politics / crypto) | 3-8 cents (wider on non-sports) |
| Order book depth | ~3.5x deeper on headline markets | Shallower outside sports |
| Resolution method | UMA Oracle (decentralized, token-voted) | Internal + CFTC oversight |
| Tax reporting | User responsibility | Provides 1099 forms to US users |
Feature matrix at a glance. Different regulators, different settlement currencies, different deposit rails — the platforms diverge where it matters for your workflow.
Part 2: Fees in Practice
Headline fee percentages hide the real story. Let's do the math on actual trades.
Trade example: buying $500 of Yes shares
| Market category | Polymarket (limit order) | Polymarket (market order) | Kalshi (limit order) | Kalshi (market order) |
|---|---|---|---|---|
| Politics | $0 + small rebate | $0 | ~$2.25 (~0.45%) | ~$9 (~1.80%) |
| Sports | $0 + rebate | $3.75 (0.75%) | ~$2.00 (0.40%) | ~$8 (~1.60%) |
| Crypto | $0 + rebate | $9.00 (1.80%) | n/a (limited crypto markets) | n/a |
| Economics | $0 + rebate | $6.25 (1.25%) | ~$2.25 | ~$9 |
The pattern
Polymarket is cheaper across almost every scenario for traders willing to use limit orders. Kalshi becomes competitive only on sports market orders -- where it already beats Polymarket on liquidity and user experience. The fee story reinforces the category story: use Polymarket for non-sports, Kalshi for sports, default to limit orders everywhere.
On $500 trades, Polymarket limit orders are cheaper across almost every category. Kalshi closes the gap only on sports market orders.
Part 3: Markets and Volume -- Who Wins What
Polymarket's strongholds
- Politics: consistently 30-40% of total platform volume in 2024-2026. Deeper liquidity, tighter spreads, truly global coverage including elections in Germany, Argentina, UK, Israel, and more
- Crypto: 260+ active markets including 5-minute BTC/ETH contracts, options-like structures, and perpetual event markets
- Geopolitics: The April 2025 Iran ceasefire market alone generated over $280M in volume. Wars, sanctions, nuclear deals, and international diplomacy all trade deeper on Polymarket
- Order book depth: headline markets typically require ~3.5x more notional to move price by a given amount compared to Kalshi
Kalshi's strongholds
- Sports: 85-90% of Kalshi's total volume. Super Bowl LX Sunday 2026 traded $871M in a single day (Polymarket did ~$701M on the same day, still massive but second place)
- March Madness 2026: generated $25M in fee revenue for Kalshi in just 4 days
- DraftKings/FanDuel crossover: sports bettors migrating from traditional books find Kalshi's interface and deposit methods easier
- Weather and logistics: Kalshi has dedicated markets on hurricane landfalls, snow-day closures, and shipping metrics that Polymarket doesn't match
Kalshi runs 85-90% sports. Polymarket’s mix is distributed across politics, crypto, and geopolitics. Different platforms for different workflows.
Part 4: Access and Onboarding
Polymarket access
- International: open to most jurisdictions with no KYC for on-chain trading. Requires a crypto wallet (MetaMask, Coinbase Wallet) funded with USDC. Onramps exist for non-crypto users but add friction
- US: re-entered via the December 2025 QCEX acquisition ($112M). Currently invite-only with a waitlist of about 1 million users. Typical wait 6-12 weeks. Full open access expected Q3-Q4 2026
- Blocked states: Nevada, New York, New Jersey, Connecticut have pending legal challenges. Trading from those states is not supported even with an invite
Kalshi access
- US: live and open in 40+ states. No waitlist, no invite, straightforward signup. ACH, debit card, wire, Apple Pay, USDC all supported
- International: announced 140-country expansion in October 2025 but rollout is uneven. Users in India, Brazil, and Nigeria have reported issues. Brazil is targeted via an XP brokerage partnership
- Restricted jurisdictions: 38 countries blocked, including Canada, France, UK, Russia, Singapore
The access calculus
If you are in the US and want to trade today, Kalshi is easier to get started with. If you are outside the US, Polymarket is usually the only realistic option with open access. If you care about specific state availability, check both platforms' current jurisdiction lists before depositing -- regulation is moving fast.
US access map. Kalshi is live in 40+ states, Polymarket is invite-only with blocked states (NY, NJ, NV, CT) pending legal resolution.
Part 5: Resolution -- The Most Underrated Difference
How markets resolve changes everything about your risk profile. The two platforms use fundamentally different systems.
Polymarket: UMA Oracle
- Decentralized resolution via UMA token holders voting
- Whitelisted proposers submit the outcome, with a $750 bond and 2-hour challenge window
- Disputes escalate to Data Verification Mechanism (DVM) voting, takes 4-6 days
- Voting is token-weighted. Approximately 40%+ of voting power concentrated in a small number of whale wallets
- Known governance attack cases: Ukraine minerals deal ($7M impact), Fort Knox gold audit ($3.5M), certain UFO-declassification markets
- Polymarket has overruled UMA exactly once (the Barron Trump / DJT token market)
Kalshi: Internal Resolution
- Kalshi's internal team resolves markets based on pre-declared sources
- CFTC oversight provides the regulatory backstop
- More predictable outcomes, fewer controversy cases
- More centralized -- you are trusting Kalshi and the CFTC, not a token-voting system
- Polymarket and Kalshi occasionally resolve the same nominal event in opposite directions because the rule wordings differ
For large positions, resolution mechanism matters as much as price. A $50K Yes bet on an ambiguous Polymarket rule can be flipped by a UMA dispute that never would have happened on Kalshi. Traders who understand this often prefer Kalshi for their biggest positions in politically charged markets and use Polymarket for categories where resolution is objectively verifiable.
UMA Oracle vs. Kalshi internal resolution. For large ambiguous-rule positions, the resolution mechanism is often more important than the entry price.
Part 6: The 2026 Regulatory Landscape
The US regulatory environment is shifting fast. Key facts as of April 2026:
- Federal court ruling (April 2026): The Commodity Exchange Act preempts state gambling laws for sports event contracts on CFTC-registered DCMs. Major win for Kalshi and other federally-registered platforms
- Congressional bills: "Prediction Markets Are Gambling Act" and "BETS OFF Act" would restrict certain contract types. Neither has passed. Both faces uphill paths
- CFTC rulemaking: over 800 public comments submitted in the active rulemaking on prediction markets. Comment deadline April 30, 2026
- State-level pushback: Nevada, Arizona, Connecticut actively challenging both platforms. CFTC has filed counter-suits claiming exclusive federal jurisdiction
- Industry growth: 13 federally regulated prediction market platforms now serve US users in 2026, up from 2 in 2023
Part 7: Other Platforms Worth Knowing
| Platform | Status | Best use case |
|---|---|---|
| PredictIt | Active, CFTC-approved Sep 2025 | Niche US politics, especially down-ballot races; $850 position caps |
| Metaculus | Active, play-money | Research-grade calibration, long-range forecasting, academic integration |
| Manifold Markets | Active, play-money | User-created markets, community experimentation |
| DraftKings / FanDuel | Launched prediction event-contract products in 2025 | Sports bettors who want DCM-regulated event contracts without leaving their existing sportsbook |
| Augur | Effectively defunct | Pioneered decentralized resolution but never achieved meaningful liquidity |
Decision tree: pick your profile, follow the branches. Most $10K+ accounts end up using both platforms for category specialization and resolution hedging.
Part 8: Which Platform Should You Choose?
| If you are... | Choose | Why |
|---|---|---|
| Crypto-native trader | Polymarket | Zero maker fees, USDC settlement, deepest crypto markets |
| US sports bettor | Kalshi | 85-90% sports volume, easy deposits, live in most states |
| Political speculator | Polymarket | Deeper liquidity, tighter spreads, 0% fees on politics |
| Algorithmic / API trader | Polymarket | Clean CLOB architecture, 3.5x deeper book, py-clob-client SDK |
| Compliance-focused | Kalshi | Longer regulatory track record, 1099 forms, simpler audit trail |
| International user | Polymarket | Actually globally accessible; Kalshi's international rollout is spotty |
| US beginner, no crypto | Kalshi | ACH / debit / Apple Pay, no wallet setup required |
| Non-US beginner | Polymarket | Only realistic option with clean access and full market breadth |
| Weather / logistics trader | Kalshi | Dedicated hurricane, snow, and shipping contracts |
| Geopolitics trader | Polymarket | Iran, Ukraine, Israel, Taiwan -- all deeper on Polymarket |
Worked cross-platform check: 2028 presidential Republican nominee
Suppose the same question — “Will the Republican nominee in 2028 be candidate X?” — is trading 48 cents on Polymarket and 53 cents on Kalshi. Tempting to sell Polymarket Yes at 53 (short exposure) and buy Kalshi Yes at 48, locking a 5-cent spread.
Before you do it, read both rule sets. If Polymarket resolves on “official RNC nomination at the national convention” and Kalshi resolves on “any major news outlet calls the nomination,” the resolution triggers can fire at different times. A candidate dropping out mid-convention could resolve one market Yes and the other No. Your “arbitrage” just became a fully-exposed bet on a rule detail you never read.
Only when the resolution criteria are identical word for word does a price gap become genuine arbitrage. In practice that is rare. Most cross-platform gaps are divergent-resolution risk premiums, which is why they persist.
Part 9: Using Both -- The Professional Approach
Most serious traders with $10K+ bankrolls end up with accounts on both platforms. The reasons are concrete:
- Cross-platform price comparison: the same event can be priced 3-8 cents apart. Sometimes that gap is real arbitrage (same resolution rules), sometimes it's different resolution criteria -- you can only tell by reading both rule sets
- Resolution hedging: if you have a large winning position on Polymarket and you're worried about a UMA dispute, a smaller counter-position on Kalshi acts as insurance
- Category specialization: politics/crypto/geopolitics on Polymarket, sports/weather on Kalshi. Each platform shines in its lane
- Liquidity optionality: for large orders, check both books. The platform with deeper liquidity at your price gets the trade
Not arbitrage, not always
The same nominal market can resolve differently on each platform because the rule wordings differ. What looks like risk-free arbitrage is often divergent-resolution risk. Always read both rule sets before assuming a price gap is a free lunch.
Part 10: Validated Pro Tips for Running Both
Ten habits from traders who run dual-platform books
- Maintain parallel watchlists. Every market you trade on one platform should have a tag for whether the counterpart market exists on the other. Check price gaps weekly.
- Read both rule sets before assuming arbitrage. The 2024 US government shutdown market split because Polymarket required “OPM issues announcement” and Kalshi required “actual shutdown exceeding 24 hours.” Same event, different payouts.
- Hedge big UMA-dispute risk with a smaller Kalshi counter-position. When a Polymarket position crosses 5% of your bankroll on a legally-ambiguous topic, size a 0.5-1% counter position on Kalshi. You burn a little EV and sleep soundly.
- Kalshi for sports, Polymarket for global politics. The volume advantages are structural. Super Bowl LX cleared $871M on Kalshi vs $701M on Polymarket in a single day. Iran Ceasefire cleared $280M on Polymarket alone.
- Use Kalshi for US tax simplification. 1099-MISC forms for Kalshi winnings above IRS threshold cut your accountant’s workload in half. Polymarket reporting is entirely user-side.
- Use Polymarket for zero-fee politics. 0% politics/geopolitics taker fees on Polymarket beat Kalshi’s 0.40-1.80% for every election, every time.
- Keep separate capital allocations. 70% of bankroll in the platform matching your primary category, 30% in the other. Don’t let funds drift based on which UI feels friendlier that week.
- Price-check large trades across both books. For any trade above $5K, pull both platforms’ order books. A 3-cent gap on a $10K position is $300 — worth 60 seconds of comparison.
- Set resolution alerts on both. Both platforms publish resolution timelines in advance. A single spreadsheet tracking expected resolve dates on both books prevents forgotten positions.
- Review regulatory news weekly. CFTC rulings, state lawsuits, and congressional bills change which platform is accessible to you. A 10-minute Friday check keeps you ahead of the waitlist and access changes.
When to use which platform — quick reference
| Situation | Platform | Reason |
|---|---|---|
| Super Bowl / March Madness bets | Kalshi | Deeper sports books, DraftKings-style UX |
| US election politics | Polymarket | 0% fees, deeper liquidity, global coverage |
| Hurricane or weather market | Kalshi | Dedicated NOAA-based contracts |
| Middle-East conflict market | Polymarket | Kalshi regulation bans war-related contracts |
| BTC price end-of-month | Polymarket | Kalshi crypto coverage is thin |
| Large position with UMA risk | Both (hedge) | Primary on Polymarket, hedge on Kalshi |
| US beginner, no crypto | Kalshi | Apple Pay / ACH deposits |
| Non-US trader anywhere | Polymarket | Only realistic option in most jurisdictions |
