How We Test and Rate Prediction Markets

At Sports Illustrated, we test prediction market platforms the way real traders use them: Opening an account, depositing funds, trading event contracts, waiting for settlement, and withdrawing winnings. Our reviews cover both desktop and mobile experiences, using real-money transactions to assess each step.

We examine everything from account verification and trading costs to contract execution and payout speed, with our findings contributing to seven scored categories that determine each platform's overall rating.

🧪 Inside SI's prediction market testing process

Sports Illustrated evaluates the top prediction market apps through hands-on testing, real-money trading, and expert analysis. Our reviewers examine the complete user experience, from account registration and deposits to contract execution, settlement, and withdrawals.

Here's a snapshot of the testing standards behind our prediction market reviews:

Our ratings reflect the platform features, trading conditions, and promotional terms available at the time of testing. Market prices, execution times, fees, and withdrawal processing can change. When transaction results are illustrated rather than independently documented, we identify them as examples.

Our prediction market reviews combine years of sports betting industry experience, firsthand trading knowledge, and a structured testing methodology. Sports Illustrated's specialists evaluate platforms such as Kalshi, Polymarket, and FanDuel Predicts to help readers understand trading costs, market selection, promotional offers, and the overall user experience.

Our prediction market expertise at a glance

Our coverage is produced by specialists who actively follow sports prediction markets, including Geoff Ulrich and Kyle Collis. Together, they bring well over a decade of experience in sports betting and trading, with firsthand knowledge of platforms including Kalshi, Polymarket, and Novig.

SI's evaluation process looks beyond advertised welcome bonuses and headline features. Our methodology examines account registration, trading costs, contract pricing, liquidity, platform usability, settlement rules, and withdrawal options to help readers identify each platform's advantages and limitations.

Brian Giuffra, VP of Betting Content at Minute Media, supports editorial oversight and has been with the company since 2016.

Readers can learn more about the experience and credentials of the specialists behind our reviews by visiting the author profiles linked above. Each review also identifies its author, so readers can see who wrote the analysis.

A welcome offer or new user bonus is only worth what you can keep. That's why we score our top prediction market promos separately from platform tests, and why the advertised figure (or the total bonus amount) plays a small part in our result.

For example, a "$1,000 deposit bonus" that requires a 5x playthrough and high trading volume, expires in a week, or only applies to long-shot contracts can be worth far less than a $100 bonus with clear terms, a small deposit requirement, and no qualifying trade.

Before we assess any offer, we open an account, observe community feedback and reviews, read the full promotional terms, and, where the platform allows, complete the qualifying steps ourselves.

We then judge the offer on five factors.

How we work out the real value

We translate each offer into what we call effective value: the amount a typical new trader could reasonably expect to withdraw after meeting every condition.

We also look at the required deposit, the capital exposed while qualifying, the required trading volume, and the share of the reward that can be withdrawn from the account.

Offers where the money can only be used as trading credit are valued below offers that pay out in withdrawable cash.

What we don't do

We do not rank offers by size, and we do not let a promotion offset weak fundamentals. Welcome offers carry 5% of a platform's overall rating (see the weighting table below). Because offers are short-term and can change without notice, we record the terms we tested, note the date, and update the review when the platform changes them.

Our goal is simple: to point readers toward welcome offers with clear, achievable requirements and real value, not simply the biggest number in the advert.

Every platform's rating is based on the same real-money tests, conducted the same way on desktop and mobile. Each test step contributes to one or more of seven scored categories, which are combined using the weights below. 

We give the most weight to the categories that determine whether a trader can enter a market, trade at a fair price, and withdraw their money. Liquidity, resolution reliability, and trust rank highest, followed by variety, fees and limits, and deposits and withdrawals.

Why the weights look like this

In our view, most of the difference between a good and a poor prediction market comes down to three things: whether you can trade size without moving the price, whether contracts settle the way the rules say they will, and whether withdrawals arrive on time. These categories carry the most weight (55% combined, counting deposits and withdrawals). 

How the overall rating is calculated

Each category is scored on its own, multiplied by its weight and added together to give the overall rating. Any deal-breaker cap (see below) is then applied, so a strong score in one area cannot hide a serious problem in another.

Where trader feedback fits

Our own testing sets the score, but it is not the only thing we look at. We also follow app store reviews, reader messages, and public trader discussions to spot recurring problems, such as a settlement that looks wrong or withdrawals that stall. When the same issue shows up repeatedly, we try to reproduce it in our own account or put it to the platform, and we only adjust a score if we can confirm it. 

Deal-breakers that affect our ratings

Some problems are serious enough to cap a platform's rating however well it scores elsewhere. We apply these caps after the category scores are combined, so a high score for liquidity or bonuses cannot hide a failure that puts a trader's money or access at risk.

How caps are applied and lifted

We explain the reason for any cap on the platform's review page, along with the date it was applied. When a platform fixes the problem, for example, by publishing clearer settlement rules, clearing a withdrawal backlog, or adding round-the-clock support, we retest and update the rating. 

Our priority is trader protection. Strong promotions or an extensive market selection should never outweigh significant concerns about fund access, transparent settlement or regulatory compliance.

Every review starts before we create an account or deposit a dollar. We first confirm the platform is legitimate, open to U.S. traders, and has public rules. We don't rate a platform that fails any of these checks, no matter how polished its app looks.

Platforms that are on a waitlist or still in pre-launch, such as ROLR, may appear on our pages for reference, but we do not rate them until they are live and we have completed our testing.

Why availability varies by state

Rules for sports event contracts differ across the country, so what a trader can access in one state may not be available in another. We rate the experience most U.S. traders can expect, and we flag any restrictions in each review so you can see what applies where you live. For a closer look at your state, see our guides for California, Florida, Georgia, New York, and Texas.

Example: how we verify state access on OG

Published availability lists can lag behind what a platform actually allows, so we confirm access ourselves. Here is how that check works for OG, one of the platforms we test.

1. Read the rules first. We review OG's published terms and help pages for any stated state limits, then compare them with the state guides on our site.
2. Start the sign-up flow. We begin registration from a device physically located in the state, select the state of residence and note whether the platform accepts or blocks us.
3. Run the location check. We complete the platform's location verification on desktop and mobile, because access can depend on where you are, not only where you live.
4. Browse the live market list. We open the sports and non-sports categories and record which contracts are visible and which are missing or locked.
5. Record the result. We log the state, device, date and what we could and could not access, and we repeat the test when the platform updates its rules.

That testing sorts a state into one of three groups. Here is how OG's access looks across the U.S. at the time of our review:

If you want to confirm your own access before you deposit, start OG's sign-up screen, choose your state, and let the location check run.

If the market list shows no sports categories, or the app blocks you, that is the platform's current rule for your location. Rules change, so check again if your state's status is different from what you expected.

Once a platform clears our legal and safety checks, we open a real account and put real money in it. This is where many traders first run into friction, so we time every stage and record exactly what happens.

The results feed our verification, deposits, and withdrawals score, which counts verification speed alongside the range of funding options and how reliably money moves in and out. We often repeat the funding tests on desktop and mobile and note any differences between the two.

Example: 🔷 FanDuel Predicts

Here is what this step looked like when we tested FanDuel Predicts.

A fast setup and instant deposit mean a new trader can start trading almost immediately.

A withdrawal that arrives within hours strongly suggests the platform takes getting money out as seriously as getting it in. We repeat the withdrawal test later in our process, as described in Step 6, so a platform has to deliver on both sides of the account to be considered one of the top prediction markets for payouts.

Results reflect conditions on the day we tested and can vary by payment method, account history, and bank.

Before we look at the trading screen, we look at the product: what a platform lets you trade, how clearly each contract is written and how easily you can get in and out. Three questions drive this step.

A platform with hundreds of markets is not necessarily a good one. A contract with vague wording is a risk before the first trade, and a market with no one on the other side is a problem when you want to sell. That is why we read the rules and test the order book on the same markets across every platform.

Example: the Super Bowl winner test

The Super Bowl winner market is our benchmark for depth because every platform we review lists it, it has a clear outcome, and it mixes busy contracts with quiet ones. We compare the same teams on each platform at the same time, so any differences come from the platform, not the news cycle. For each one, we pick three contracts: the favorite, a mid-priced contender, and a long shot.

We also compare the favorite with the long shot, because a platform that is liquid only on its most popular contracts is much less useful than one with workable spreads and depth throughout the field.

Example result: 🟢 Kalshi

When we tested Kalshi in October 2026, the Super Bowl winner market had roughly $206.6 million in total trading volume. We looked at the order book on the favorite, the San Francisco 49ers, and on a long shot, the Atlanta Falcons.

The favorite was deep on both sides, with a one-cent spread and six figures of resting orders either way, so a trader could enter or exit a sizable position without moving the price much.

The long shot held up better than we expected: buyers could find about $61,000 of supply within 2¢ of the best ask. The weak spot was the other side. Only about $3,000 sat on the bid at 1¢, so anyone trying to sell a large long-shot position would face a thinner market. A one-cent spread is also a bigger share of a 2¢ contract than of a 16¢ one.

That is the pattern we look for in this step: the platforms with the best liquidity are the ones that stay workable on both sides of the field, not only at the top.

Where a platform does not publish trading volume in a comparable form, we say so, and we weight spreads, depth and fill quality more heavily. Prices and volumes move constantly, so we record the date and time of every trading snapshot and price.

After reviewing eligibility, verification, funding, and markets, we start testing real trades. This step shows what trading costs once the price on the screen turns into money leaving your account, and how easy the platform is to use while you do it.

Example: a $100 order on Novig

For our Novig example, we used the Cowboys-at-Eagles NFL game and entered a $100 order on the Eagles to win.

What stands out is the order book size compared with the trade. A $100 order is a small fraction of the $46,462 sitting at the best price, so it should fill in full at that price with no slippage.

The half-point gap between the two sides is a simple way to see what a platform charges for being in the middle: the narrower it is, the less a trader gives up before the game starts. The order slip also shows the payout before we confirm, so it's easy to see exactly what is at stake.

Combos and parlays

Combos, which many platforms also call parlays, bundle several outcomes into one trade. They pay more when they win, and they hide more of the cost, so we test them separately from single-market trades.

How we compare combo prices

We price each leg separately, multiply the probabilities, and compare the result with the platform's combo price. The gap is the extra cost of bundling. For example, two legs priced at 60% and 50% multiply to 30%. A combo priced at 33% costs three percentage points more than the legs separately, and that premium usually grows as you add more legs.

We repeat the comparison at several leg counts because a platform that prices two-leg combos fairly can still charge heavily on longer ones.

Early exits and void legs

We check whether a combo can be sold before it settles by placing one and looking for an exit price. When an exit is offered, we compare it with the value of the remaining legs and note whether the combo can still be sold once some legs have finished. For void legs, we read the rules before we trade, then check the platform's help pages and trade confirmations to see what the platform says it will do. The best platforms explain whether the combo continues with the remaining legs, how they recalculate the payout, and when they return the stake.

A prediction market is only as good as its last step: paying out correctly. We follow contracts through settlement, check each result against the platform's rules, and assess how the platform protects the money and the account throughout.

These checks feed our Resolution reliability and trust score. They also explain why unclear settlement rules and weak fund protections are treated as deal-breakers.

Example: account security on 🟢 Kalshi

Account security is easy to overlook until something goes wrong, so we read each platform's documentation and test the setup ourselves. Here is what Kalshi's help center says about it.

We like that Kalshi offers an authenticator app option and publishes clear recovery steps. Text codes are convenient, but an authenticator app is generally the stronger choice, so we recommend turning it on. The withdrawal hold shows another security layer, and it also shows why we measure withdrawal times separately in Step 6.

Where customer money sits

We also look at who holds trader funds. Kalshi's help center says it holds deposited money with its clearinghouse, which the CFTC has approved to clear its contracts. That is useful, but it is not the same as federal deposit insurance. We tell readers what a platform says about holding funds, and we mark clearly where a platform does not explain whether customer money is kept separate from its own.

Getting paid is the most important part of a prediction market. After our trades settle, we request a withdrawal and time how long it takes for the money to reach a bank account, debit card, or supported wallet, using the same amount and method on every platform where we can.

Three stages, three different timelines

A platform's "withdrawal time" can mean different things, so we measure each stage separately.

For every platform, we also log the payment methods offered, minimum withdrawal amounts, fees, verification requirements, and any delays caused by security holds. A fast headline number means little if the funds sit in a hold first, so we count the full wait from request to arrival.

Kalshi vs. Polymarket US: How do withdrawals compare?

Kalshi and Polymarket U.S. both let U.S. traders withdraw dollars, but the experience depends on the payment method and the account. The table compares what each platform publishes with what we found in testing.

Kalshi publishes the clearest rules on holds, including which methods carry them and which do not. That makes it easy for a trader to plan around the wait. Polymarket US supports debit card and bank withdrawals, but we found fewer guarantees on arrival time in its public information, so we judge its speed by test transactions and don't assume it matches Kalshi.

How this affects the rating

We test the same methods on each platform whenever possible, so the comparison reflects real experience, not advertised speed. These results feed our deposits and withdrawals score. If a withdrawal goes unexplained for more than 10 business days after the funds become eligible, we trigger a rating review.

Every platform works well when nothing goes wrong. What matters is how it responds when something does. We try to send each platform similar support questions so we can compare the answers fairly.

1. An account question, such as a login or verification problem.
2. A money question, such as the status of a deposit or withdrawal.
3. A settlement question, such as why a contract resolved the way it did.

For each one, we record:

These results feed into our User experience score. A platform that cannot help with urgent account or settlement issues outside business hours may see that score drop, as explained in our deal-breakers below.

At Sports Illustrated, our prediction market reviews are guided by editorial independence, transparency, and accuracy. Our goal is to give readers trustworthy information based on firsthand testing, research, and clear rating criteria.

How we make money

Sports Illustrated may earn a commission when readers register or trade through links on our pages. However, prediction market operators cannot pay for a higher rating, better ranking, or favorable review. Commercial partnerships do not determine our editorial recommendations.

Who determines our ratings?

Our prediction market ratings are determined exclusively by SI's editorial team, based on the seven scoring categories outlined above. Commercial partners do not have access to unpublished ratings and cannot influence, approve, or change scores before publication.

How often do we update our reviews?

We regularly revisit our prediction market reviews to keep information accurate and relevant. A complete reassessment of every rated platform takes place [review frequency to be confirmed].

We also prioritize immediate updates and targeted re-testing whenever a platform changes its trading fees, welcome offers, state availability, payment methods, or major features. Significant court rulings, regulatory decisions, and changes to a platform's operating status also trigger an editorial review.

Corrections and reader feedback

We take accuracy seriously and encourage readers to report outdated information or factual errors. Corrections can be submitted through [confirmed SI editorial contact method].

When we verify a material error, we update the affected content and include a dated correction notice explaining what changed.

For more information about our commitment to independent recommendations and commercial transparency, read Sports Illustrated's Affiliate Link Policy.

Prediction markets involve financial risk, and traders can lose their entire investment in an event contract. At Sports Illustrated, we encourage readers to establish a budget, understand the risks and avoid trading money they cannot afford to lose.

Minimum age requirements vary by platform. Kalshi and Polymarket US generally accept users aged 18 and older, while platforms such as Novig require traders to be at least 21. Users must also meet their platform's identity verification and state eligibility requirements.

Many prediction market platforms offer responsible trading tools to help users manage their activity:

• Deposit limits: Kalshi allows users to set monthly funding caps, while Novig offers daily, weekly and monthly deposit limits.
• Loss and trading limits: Some platforms, including Novig, provide controls designed to restrict trading activity, losses or financial exposure.
• Trading breaks and self-exclusion: Platforms such as Kalshi and Novig allow users to temporarily suspend trading or exclude themselves for longer periods.

We examine these protections as part of our platform reviews and encourage traders to use them before problems develop.

Help is available. Anyone experiencing difficulty controlling their trading or gambling can contact 1-800-GAMBLER or the National Council on Problem Gambling's current national helpline at 1-800-MY-RESET. State-specific resources include 1-800-BETS-OFF in Iowa, 1-800-NEXT-STEP in Arizona and 877-8-HOPENY in New York.

Readers can also find additional guidance in Sports Illustrated's responsible gambling resources or access the National Council on Problem Gambling's state-by-state support directory.