Prediction Markets vs Sports Betting: Key Differences & Costs Compared

AbstractA sportsbook is a dealer that sets odds and takes the other side of every bet; a prediction market is an exchange where participants trade with each other and market makers. We compare them on structure, cost and price quality. At a standard −110/−110 line a bettor gives up 4.55% of stake in expectation; on an exchange quoting 50/51 with a 1.75¢ taker fee the equivalent cost is about 4.3%, and a resting order that is filled can cost nothing. The bigger differences are elsewhere: exchanges do not limit winning customers, and their prices are not shaded by a house's risk management.

House versus exchange#

Table 1. Structural differences.
	Sportsbook	Prediction market (exchange)
Counterparty	The bookmaker	Other participants and market makers
Price set by	Bookmaker's traders and models	Supply and demand in an order book
Margin	Overround built into odds	Bid-ask spread plus trading fees
Can you sell before the event?	Sometimes (cash-out, at the book's price)	Yes, at the current bid
Can you take the other side?	Only by betting the opposite outcome	Yes: sell Yes or buy No
Winning customers	Often limited or restricted	No account-level limits on winning
Range of questions	Sport, some novelty markets	Economics, politics, weather, culture, sport

The deepest difference is incentives. A bookmaker profits when customers lose, so it manages its book by shading odds and limiting customers who win consistently. An exchange profits from volume; its participants' winnings come from other participants, not from the venue. That is why sharp bettors gravitate to exchanges, and why exchange prices are usually the better probability estimate.

What it costs: a worked comparison#

Sportsbook at −110/−110. Stake $110 to win $100 on a true 50% event. Expected value $0.5 \times 100 - 0.5 \times 110 = - 5$ , which is 4.55% of the stake.

Exchange, taking liquidity. The same event quoted 50¢ bid / 51¢ ask. Buy at 51¢ plus a taker fee of about 1.75¢ (Kalshi's published 0.07 coefficient at large size): all-in cost 52.75¢ for an expected payout of 50¢. Expected loss 5.21% of the amount paid.

Exchange, providing liquidity. Post a bid at 50¢ and wait. If filled, and if maker fees are zero on that market, expected value is zero at a true 50%. The trade-off is that resting orders fill more often when the price is about to move against them (see adverse selection).

Table 2. Cost of taking a view on a true 50% outcome. Fee arithmetic from our fee note; maker fees vary by market.
Route	All-in cost for a 50% outcome	Expected loss per $ committed
Sportsbook −110	$1.10 per $1 of profit	4.55%
Exchange, taker at 51¢ + 1.75¢ fee	52.75¢ per contract	5.21%
Exchange, taker at 51¢, single contract (2¢ fee)	53¢	5.66%
Exchange, maker at 50¢, no maker fee	50¢	0.00% (before adverse selection)

For a taker, a two-way −110 line and a tight exchange market cost about the same. For anyone who can wait for a fill, the exchange is far cheaper. Costs diverge further for favourites, because exchange fees scale with $P (1 - P)$ while bookmaker margins often do not; see prediction market fees.

Which price is the better forecast?#

A sportsbook's posted odds mix three things: its estimate of the probability, its margin, and its book position. A book that has taken heavy action on one side shades the price to attract the other, which distorts the implied probability. An exchange price also mixes things (spread, fees, the biases of whoever is trading) but has no house position to protect, and the mid is unaffected by any single participant's margin.

In liquid markets the two converge, because professional traders move between them. In thin markets, the exchange mid can be noisy and a large bookmaker's line can be the better estimate. The practical answer is to use both, after removing the bookmaker's margin (how to read odds).

Regulation, briefly#

In the US, sportsbooks are licensed and taxed by individual states. Event contracts listed on CFTC-designated contract markets are regulated federally as derivatives. Whether sports-related event contracts fall under federal or state jurisdiction is being contested in courts and legislatures as of 2026. Our legal overview summarises the state of play. Tax treatment can also differ between the two and by jurisdiction; that is a question for a tax adviser, not for this page.

Questions#

What is the difference between a prediction market and a sportsbook?

A sportsbook sets odds and is your counterparty; it profits when customers lose and often limits winners. A prediction market is an exchange where you trade with other participants and market makers; the venue earns fees and does not take the other side of your trade.

Are prediction markets cheaper than sports betting?

For taking liquidity, costs are similar: about 4.5% of stake at −110 versus about 4.3% on an exchange quoting a 1¢ spread with a 1.75¢ taker fee. Resting orders on an exchange can be much cheaper, sometimes free where maker fees are zero.

Do prediction markets limit winning traders?

Exchanges do not take the other side of trades, so they have no reason to limit customers for winning. Position limits set by rules or regulators can still apply.

References#

Kalshi. Fee schedule (published PDF), accessed October 2026.

DisclosureThis note is research and education. It is not investment advice or an offer to trade, and nothing in it describes the firm's own results.