On Kalshi, a large event-contract trade has three routes: work it on the order book, request private quotes through Kalshi’s RFQ system, or, if both parties are eligible contract participants trading at least 25,000 contracts (50,000 in sports), negotiate a block trade under Kalshi’s rulebook. Polymarket’s international exchange has no rulebook block facility, but it does settle privately negotiated trades through an invitation-only RFQ Trades API used by approved partner platforms; otherwise large orders are worked on the order book. Polymarket US, the CFTC-regulated exchange, does permit blocks of at least 100,000 contracts. Whichever way the event leg fills, the crypto exposure it creates can be hedged with Deribit options packaged through RFQ on Deribit, Paradigm or Derive.

Block trading on Kalshi

RFQ for size between the book and a block

Kalshi’s request-for-quote system works on any listed market, including combo markets, through the API, WebSocket and FIX. The requester sends a market and a size. Market makers reply privately with a YES bid and a NO bid for the full size, and no maker sees another’s quote. The requester accepts one side, the maker confirms within a short window, and the trade executes. It is the practical tool for clips too large to sweep the book but too small or too urgent to negotiate as a block. The API mechanics are covered in our guide to the Kalshi API for institutional desks.

Kalshi block trades

Kalshi permits formal block trades under Rule 5.3(e) of its rulebook. The rules, as currently published:

• Both parties must be Eligible Contract Participants as defined in the Commodity Exchange Act.
• Kalshi designates block-eligible products, and its help center currently lists all listed markets as eligible.
• The minimum is 25,000 contracts for non-sports event contracts and 50,000 for sports, thresholds Kalshi self-certified with the CFTC effective July 16, 2026, and separate orders cannot be aggregated to reach it except by qualifying advisers as the rule allows.
• Price has to be fair and reasonable given the size, prevailing market data and the circumstances of the market and the parties.
• Each block must be reported to Kalshi within 15 minutes of the parties agreeing terms, and Kalshi publishes blocks separately from regular trades.
• A block does not trigger conditional orders or otherwise interact with orders resting on the book.

Two practical points follow. Kalshi contracts pay $1 at settlement, so the minimum non-sports block carries at most $25,000 of payout ($50,000 in sports), a threshold many desks will clear. And a block is privately negotiated: both accounts are pre-funded, Kalshi reviews, books and publishes it, and finding the other side is up to you or an intermediary such as an FCM or introducing broker.

Polymarket: large orders and privately negotiated trades

Polymarket’s international exchange runs a hybrid central limit order book, with orders matched off-chain and settled on-chain on Polygon. It has no rulebook block facility, but it does settle privately negotiated trades through an invitation-only RFQ Trades API used by approved partner platforms; otherwise large orders are worked on the order book. Polymarket’s own documentation states that the order book has no trading size limits but that large orders may move the price significantly.

Polymarket also runs a Combos RFQ, which serves packages of two or more market outcomes priced as one position. A request goes to connected market makers who have a few hundred milliseconds to quote, and the user accepts the best price. It is a pricing route for multi-market structures, separate from the RFQ Trades API that approved partner platforms use for privately negotiated trades.

Polymarket US is a different venue. It is a CFTC-registered designated contract market with its own rulebook, and it does allow block trades. Both counterparties must be approved Eligible Contract Participants, every block must be at least 100,000 contracts, terms are negotiated off-platform and booked by Polymarket’s team, and the trade must be submitted within 15 minutes of agreement. Blocks are currently permitted only in contracts Polymarket US designates as block-eligible, which are politics, macroeconomics and sports, so crypto contracts there are not block-eligible today. Blocks are published on a dedicated block trade data page. Before planning size on “Polymarket”, a desk should be clear which of the two venues it is trading.

Working size with execution algorithms

On the international Polymarket exchange, outside trades routed through an approved partner platform, and on Kalshi whenever a block or RFQ is impractical, size has to be worked on a thin book. Event-contract books behave differently from crypto options books. Prices are bounded between zero and one, depth often clusters within a few ticks of the touch, and books can take minutes to refill after a large print. News can reprice a contract before any algorithm reacts.

The techniques that work are familiar from other illiquid markets:

• Time slicing spreads a parent order over a window so the book has time to refill between child orders.
• Iceberg-style display shows a small quantity and replenishes it, so resting size does not advertise the full order.
• Chasing the touch keeps a passive order at the best price without crossing the spread on every fill.
• A hard limit price set before the order starts caps what the desk will pay however long the algorithm runs.
• Pausing around scheduled data releases avoids filling into the one moment the price is most likely to jump.

Measure fills against the mid when the parent order started, because on thin binary books that is where impact shows up.

Liquidity is fragmented across Kalshi and Polymarket

Many questions trade on both venues, and splitting a parent order across them reduces impact on each book. The contracts are related but rarely identical: resolution sources, settlement times, edge-case wording, collateral and fees can all differ, and capital sits in separate accounts. Buying on one venue and selling on the other leaves a spread position with resolution risk. Read both contract specifications and track both legs in one place. Our comparison of Kalshi and Polymarket for institutional desks covers the differences that matter.

Hedging the exposure with Deribit options via RFQ

A large position in a crypto price contract, such as “Bitcoin above a given level on a given date”, is a binary payoff. The closest options analogue is a tight call spread around the same strike. That spread on Deribit offsets much of the delta and volatility exposure, and in size it trades best as one package through RFQ.

Deribit’s Block RFQ accepts structures of up to 20 legs with an optional futures hedge leg, lets multiple makers aggregate into one response, and prints the whole execution at a single price. Paradigm runs a multi-dealer RFQ network for crypto options blocks. Derive’s RFQ executes multi-leg packages atomically, all or nothing at one total cost. Requesting the same package across all three gives the desk more makers competing for one structure.

The hedge is never perfect. Deribit options expire at 08:00 UTC, while event contracts settle on their own reference price at their own time. A binary’s delta spikes as expiry approaches with the price near the strike, which a call spread only approximates. Contract counts and option sizes are in different units and need careful conversion. Our guide to hedging Kalshi and Polymarket crypto contracts with Deribit options works through the sizing, and our piece on crypto options RFQ and block trading covers the RFQ side.

How Kemet supports the workflow

Kemet is a technology provider. It is not an exchange, broker, FCM or counterparty, it never holds client assets, and it does not negotiate or report block trades. Desks connect their own Kalshi, Polymarket and derivatives venue accounts using their own API keys, and Kemet rejects keys with withdrawal rights. Venue access depends on each venue’s own eligibility rules: Polymarket’s international platform, Deribit, Binance and OKX are not available to US persons directly, and US desks reach Polymarket through Polymarket US. Desks should confirm eligibility with counsel.

On the event leg, desks work orders on Kalshi and Polymarket with TWAP, Chase, iceberg and scale algorithms, with price protection on every order. Desks can split a single parent order across Kalshi and Polymarket and send requests into Kalshi’s RFQ system from Kemet. On the hedge leg, the multi-leg package builder sends options structures to RFQ on Deribit, Paradigm and Derive, and auto-hedging fires on fills against thresholds the desk sets. Event positions, including those booked through a block on the desk’s own account, sit in one portfolio and risk view next to options, futures, perpetuals and spot. More on the platform is on our prediction markets page.

FAQ

Does Kalshi allow block trades?

Yes. Under Rule 5.3(e) of its rulebook, Kalshi permits privately negotiated block trades between Eligible Contract Participants. Blocks must be at least 25,000 contracts (50,000 in sports), the price must be fair and reasonable, and the trade must be reported within 15 minutes of agreement.

Does Polymarket have block trading?

Polymarket’s international exchange settles privately negotiated trades through an invitation-only RFQ Trades API for approved partner platforms, and its Combos RFQ prices multi-leg packages. Polymarket US, the CFTC-regulated exchange, allows block trades of at least 100,000 contracts between approved Eligible Contract Participants.

How do you place a large order on Polymarket without moving the price?

Work it with algorithms: slice it over time, display only part of it, set a hard limit price and avoid filling around scheduled news. Splitting across Kalshi and Polymarket helps if the contracts resolve the same way.

What is the difference between Kalshi RFQ and a Kalshi block trade?

An RFQ is an on-exchange auction: you request a price and market makers quote privately for your full size. A block trade is negotiated privately between two eligible parties, must be at least 25,000 contracts (50,000 in sports), and is reported to Kalshi afterwards.

Can I hedge a large Kalshi Bitcoin position with Deribit options?

Yes, approximately. A tight call spread around the contract’s strike approximates its payoff, and trading it as one package through RFQ on Deribit, Paradigm or Derive gets size done at a single price. Settlement time, reference price and sizing mismatches leave residual risk you have to manage.

Talk to us

If your desk is trading size in event contracts and hedging it in crypto options, we can walk through the workflow on your own accounts. Book a demo.