Polymarket vs Kalshi: Fees, Regulation, Order Books

Polymarket vs Kalshi stopped being a simple "crypto vs regulated" comparison in 2025. Polymarket bought QCEX, a CFTC-licensed designated contract market and clearinghouse, for roughly $112M in July 2025, then relaunched to US users on December 2, 2025 with an Amended Order of Designation from the CFTC in hand. Kalshi has held that same DCM status since November 4, 2020. Both are now federally regulated in the US, and the real differences sit in settlement rails, fee math, and resolution mechanics — not in which one is "legal."

Regulation and Structure

Kalshi runs as KalshiEX LLC, the DCM, paired with Kalshi Klear LLC, its own derivatives clearing organization, so customer funds sit at a federally regulated clearinghouse. Polymarket's US business now runs through QCEX's CFTC license, giving it an intermediated, federally regulated US exchange, while Polymarket also keeps a separate international exchange that stays geoblocked to US users. Polymarket filed with the CFTC on April 28, 2026 seeking to let US users trade that offshore exchange directly, and a new CFTC probe into Polymarket opened in June 2026 — worth watching if you're trading there. Kalshi, meanwhile, won a Third Circuit ruling in May 2026 that the Commodity Exchange Act gives the CFTC exclusive jurisdiction over sports event contracts on CFTC-licensed DCMs, preempting New Jersey's state gambling law, though outcomes still vary by state and circuit.

Settlement: Crypto Rails vs Bank Rails

Polymarket collateralizes everything in USDC, wrapped into an internal pUSD token on deposit, and settles trades on Polygon. Gas is typically under a cent per transaction and often subsidized outright; bridging funds back to Ethereum mainnet can run $1–$20+ depending on congestion. Kalshi skips the crypto step entirely — it's a standard US-dollar account funded by ACH, debit card, or wire, settling through its own clearinghouse the way a securities broker would. If you don't want to touch a wallet or stablecoin at all, Kalshi's rails are simpler. If you're already comfortable with USDC and Polygon, Polymarket's deposit-to-trade path is just as fast and typically cheaper per transaction than a bank wire.

Resolution: Oracle vs Internal Sourcing

Polymarket resolves markets through the UMA Optimistic Oracle: anyone can propose an outcome by posting a USDC bond, roughly $750 for a standard question and $5,000+ for high-value markets. Uncontested proposals settle in hours; disputed ones escalate to a UMA token-holder vote that takes 4–7 days. Kalshi resolves internally against sourced data tied to the contract's settlement source, without an on-chain dispute-bond mechanism. Polymarket's model is more transparent about the dispute process itself — you can watch a bond get posted and challenged — while Kalshi's model is faster and more predictable for contracts with an unambiguous data source like CPI prints or NOAA weather readings.

Order Books: Same Concept, Different Read

Both venues run a central limit order book where price equals implied probability. Polymarket's book runs on a hybrid model: off-chain matching with on-chain settlement through the Conditional Token Framework (CTF, ERC-1155), so every fill is publicly traceable to a wallet address on Polygon. Kalshi's API (api.elections.kalshi.com/trade-api/v2) returns bids only — a YES bid at X is mathematically identical to a NO ask at $1 minus X, so the book is represented as a single-sided ladder rather than two mirrored sides. If you're building your own tooling against either API, that structural difference changes how you parse depth.

Fee Comparison Table

Dimension	Polymarket	Kalshi
Regulation	CFTC-regulated US DCM (via QCEX) + offshore exchange	CFTC-regulated DCM since 2020
Settlement	Crypto (USDC/pUSD on Polygon)	USD, US bank / clearinghouse
Resolution	UMA optimistic oracle (decentralized)	Kalshi internal + sourced data
Fees	Category taker fees $0.75–$1.80/100 (2026); many fee-free	7% × P × (1−P), max $1.75/100
Order book	CLOB, off-chain match / on-chain settle	CLOB, bids-only representation
Deposits	Crypto/USDC, card on-ramp	ACH, debit, wire
Market breadth	Very broad (politics, crypto, sports, culture, world)	Broad + strong econ/weather/Fed

On fees specifically: Polymarket's 2026 schedule (see how Polymarket's category-based fees work) only charges takers, peaks at the 50% price point, and is fee-free on geopolitical markets entirely. Kalshi's flat 7% formula (see Kalshi's fee schedule explained) applies more uniformly across categories but also peaks at 50 cents — 0.07 × 100 × 0.50 × 0.50 works out to $1.75 per 100 contracts, close to Polymarket's politics/finance/tech ceiling of $1.00–$1.25 but higher than its sports rate of $0.75. Neither fee schedule should be treated as permanent — both are recent and both venues reserve the right to adjust them, so check the official pages before sizing a position around the fee math.

Market Breadth and Liquidity

Both venues carry deep coverage of the 2026 US midterms, with 500+ active midterm markets combined as of June 2026. Polymarket's catalog leans broader into crypto, culture, and global geopolitical events; Kalshi has built out particularly strong economics and weather contracts, plus 2026 approval for Bitcoin perpetual futures (BTCPERP) that extends its product line beyond binary event contracts. If your edge is in a niche vertical — say, Fed rate decisions or NOAA temperature data — check both books, since depth on a specific contract can differ sharply even when the topic overlaps.

Which One Should You Use

Neither venue is strictly better; they solve different constraints. If you want to avoid crypto entirely and prefer a bank-rail account, Kalshi's ACH/debit/wire funding is the simpler path. If you're already running USDC and want access to Polymarket's broader catalog of culture and world-event markets — plus fee-free geopolitical trading — its Polygon settlement is cheap and fast once you're set up. Traders running spreads or arbitrage across both often keep funded accounts on each and route size to whichever book is deeper for a given contract at a given moment.

PolyMarketMaker's terminal pulls live order books, candles, and depth from Polymarket US, Polymarket's global exchange, and Kalshi side by side, so you're not tab-switching between two sites to compare a spread. PolyMarketMaker runs on Mac and Windows, Simulation $149/mo, Live Trading $299/mo.

FAQ

Is Polymarket or Kalshi more regulated?

Kalshi has been a CFTC DCM since November 2020. Polymarket became CFTC-regulated in the US after acquiring QCEX and relaunching December 2, 2025, though its separate international exchange stays geoblocked to US users.

Which has lower fees, Polymarket or Kalshi?

It depends on category and price. Kalshi's flat 7% formula maxes near $1.75 per 100 contracts at 50 cents. Polymarket's 2026 category fees run $0.75–$1.80 per 100 shares, with geopolitical markets fee-free — cheaper in some categories, comparable in others.

Do Polymarket and Kalshi use the same order book?

Both run a CLOB, but Polymarket settles on-chain via the CTF contract on Polygon while Kalshi settles through its own clearinghouse and returns bids-only depth through its API.

Can I fund Polymarket and Kalshi the same way?

No. Polymarket runs on USDC/pUSD via Polygon plus card on-ramps. Kalshi is a standard USD account funded by ACH, debit, or wire.

For a full walkthrough of getting started on the other side of this comparison, see the Kalshi trading guide, and for how a price gap between the two venues becomes a trade, see prediction market arbitrage across venues. This comparison sits within the broader Polymarket trading strategies pillar.

This article is for educational purposes only and is not financial advice. Trading involves risk of loss.