Who is paid to quote, and what that does to the book you trade against

Some of the orders you trade against on a prediction market were placed by somebody the venue is paying to place them. That is not hidden: Kalshi files each of its programmes with the CFTC, and Polymarket, Polymarket US and Opinion publish theirs in their documentation. What they show is that "liquidity" is bought in three distinct ways, each with its own conditions, and each leaving a different mark on the book a taker meets. The short version for a reader who is waiting on a position is in what your money does while you wait; this page is the long one.

How it works

Designation: an agreement with obligations

Kalshi's rulebook, version 1.29, devotes Chapter 4 to market makers. Kalshi alone decides who becomes one (Rules 4.1 and 4.2), weighing "available financial resources, relevant experience, business reputation"; the member has to sign a market maker agreement; and the designation "may be suspended, terminated or restricted by Kalshi at any time and for any reason". The obligation, in Rule 4.4(b), includes "maintaining two-sided markets within a defined spread and with a minimum depth during trading". The benefits, in Rule 4.3, may include "financial benefits, reduced fees, differing Position Limits and Position Accountability Levels, and enhanced access". Polymarket US's rulebook, dated 30 September 2026, repeats the structure almost word for word and adds "financial incentives for meeting trading volume or liquidity thresholds".

The numbers are not public. Kalshi's amendment of 3 June 2026 to its 2025 Market Maker Program filed the agreement and its Schedule II, the markets and liquidity conditions covered, as confidential appendices. What the cover letter does say is the escape clause: when the liquidity conditions for a covered product change, "a Market Maker may (without penalty) opt out of that Covered Product by giving written notice", and Kalshi "retains the right to end the Program at any time".

Rewards for resting orders: paid by the snapshot

The second kind pays for being in the book at the moment someone looks.

Kalshi's Liquidity Incentive Program, as amended on 14 October 2026 and effective no earlier than 28 October 2026, is open to every member except Kalshi's affiliates, introducing brokers, futures commission merchants and their customers, and anyone with market-making obligations in that market. During each time period, of one to seven days, the exchange takes a snapshot of the book once a second at a randomly drawn moment. Only resting orders count, only up to a target size of more than 100 and fewer than 10,000 contracts a side, counted from the best price down, and each tick away from the reference price halves an order's score (a discount factor of 0.5). A snapshot in which the book is not two-sided to the target size on both sides is excluded. The reward pool per market runs from $10 to $10,000 per business day, is published on Kalshi's Liquidity Rewards page at least 24 hours ahead, and is paid no later than a day after the period ends, in amounts of $1.00 or more.

Polymarket's liquidity rewards, as its documentation read on 9 October 2026 describes them, work the same way with different constants. Each incentivised market sets a maximum spread and a minimum order size; the book is sampled once a minute at a random offset, up to 1,440 samples a day; an order's score is the square of how far inside the maximum spread it sits, measured from the size-adjusted midpoint; and outside a midpoint of 10 to 90 cents only two-sided liquidity scores at all. Payouts under $1 are not made.

Selected providers: paid by the week, chosen by auction

Kalshi's Designated Liquidity Provider programme, in the form filed on 14 October 2026 and effective no earlier than 28 October 2026, sits between the two. Kalshi announces a bidding period of at least three days; members who have signed a market maker agreement bid the smallest weekly reward they would accept to meet the requirements; Kalshi selects up to the target number of providers, never more than ten per series. The requirements are a maximum spread, a minimum size within that spread, coverage of every market in the series, and a minimum uptime, with the reward cut pro rata below it and paid at nothing at or below 50% uptime; uptime between midnight and 8 a.m. Eastern counts at half weight. Each incentive period runs 30 to 90 days and the programme ends no later than 1 December 2027. The filing replaces the earlier flat cap of $50,000 a week with per-category weekly caps, and those caps and the spread and size ranges are in a confidential appendix.

The filing says what the money is for: "markets that are new or would otherwise have more limited trading activity", chosen by criteria "such as a series' nascency and observed execution costs relative to the mid-spread".

Rebates: paid by the fill

The third kind pays only when somebody trades against you.

• Polymarket funds its maker rebates from taker fees, according to its maker rebates page as read on 8 October 2026: 20% of the fees in crypto markets, 15% in sports and 25% in the other fee-charging categories, shared daily among the makers in each market in proportion to the fees their filled orders would have generated. Geopolitics markets charge no fee and so fund no rebate.
• Polymarket US, under the fee schedule effective 19 October 2026, pays the rebate at the point of the trade, but only by tier: below $10,000,000 of maker volume in the prior calendar month there is none, and above it the coefficient is −0.0035, −0.0070 or −0.0104, which the schedule describes as about 5%, 10% or 15% of the standard taker fee. Combo fills carry no maker rebate.
• Opinion returns 50% of the taker fee on every fill to the maker, automatically and on every market, according to its maker rebates page. The rebate is computed on the fee the curve produces, not on a minimum fee or a referral discount the taker actually paid.

Kalshi adds one constraint across all of its programmes: where a trade qualifies for several per-trade incentives only the largest applies, and incentives are cut "to the exact extent necessary to prevent trading conditions with net-negative (maker + taker) fees on a per-trade basis".

What it means for the book a taker meets

Depth follows the reward list. Every programme above pays per market, and every one of them publishes or configures which markets qualify. A market that is on the list this week has a reason for somebody to be in it; the market next to it may have none. On Kalshi the list for the reward programmes changes with each period, at most seven days for the incentive programme and at most ninety for designated providers.

The reward is for resting inside a band, not for size beyond it. Polymarket's formula stops counting past a maximum spread. Kalshi's halves an order's weight with every tick from the reference price and stops counting once the target size is filled from the best price down. Both reward the price levels nearest the middle and nothing far from it, which is consistent with a book that is tight for an order of the target size and thin behind it.

Paid and unpaid quotes queue together. Kalshi's designated provider filing says the programme "does not afford participants any execution priority over non-participants" and does not alter the matching engine; rewards are computed after the period. The same price, the same queue.

The obligation is somebody else's contract. A taker cannot read a market maker's spread or hours, because they are filed as confidential, and a designated market maker may opt out of a product when its conditions change. A quote that was there yesterday is evidence of a programme, not a promise.

A paid quoter can be related to the firm you trade through. Kalshi excludes its own affiliates from both of its October 2026 programmes. Fanatics Markets' futures commission merchant discloses that an affiliate under common control, Morton St. Market Maker, LLC, is a participant of one or more designated contract markets and "may receive programmatic incentives offered by a DCM", and says the affiliate has no access to its customers' non-public order information.

On multi-leg contracts the payment is routed to the legs. Kalshi's sports-prop combo programme distributes up to 25% of the fees collected on each combo market to the makers in its prop legs, such as a player's points, because those books are what the combo is priced from. What a combo contract is explains why the combo itself has no book.

What you can do about it

Check whether the market you are about to trade is on a reward list. Kalshi publishes its incentivised contracts and periods at least 24 hours in advance; Polymarket exposes each market's reward settings, the maximum spread and minimum size, in its market data. A market with an active reward has a reason for quotes to be there today; a market without one is priced by whoever turned up.

Size against the band, not against the top of the book. If an order is larger than the target size the programmes reward, assume the depth behind the best price is thinner than the best price suggests, and look at the levels behind it before sending a market order. Stream an order book does that from code, and where the liquidity comes from explains the four numbers that say whether a book is deep.

Read the period end as a date that matters to you. A position you expect to exit before resolution depends on somebody quoting on the day you exit. An incentive period that ends before then is a reason to expect a wider book on the way out.

Know which side of the rebate you are on. On venues that rebate makers, a taker's fee is partly the maker's income; what a trade actually costs converts the fee itself, and a resting order is priced differently from a market order.

If you trade through a broker, ask who quotes. Fanatics Markets' futures commission merchant discloses its affiliated market maker in its legal pages, not in the app; the same question is worth putting to any broker before you fund an account.

The quoting tools in this catalogue, such as the Polymarket LP Tool, are built around these reward bands; the venue cards for Kalshi, Polymarket and Polymarket US carry each venue's fee schedule.