Prediction Market Platform Selector and Contract Risk Checker
Answer first
Select the venue only after you pass eligibility. For an eligible international crypto-native workflow, consider Polymarket international. For an eligible designated contract market account, compare Polymarket US and Kalshi at the exact contract level. For an eligible Interactive Brokers client who wants published-outcome event contracts, consider ForecastEx. Return no-platform when venue, access, rules, cost, funding, or exit cannot be verified.
This tool does not select an outcome or estimate what will happen. It checks whether a contract is clear and executable enough to research. Similar headlines do not make contracts identical. The selector compares definitions, sources, deadlines, correction rules, settlement, price, spread, depth, fees, collateral, and account restrictions before it returns a fit.
Decision table
| Decision | Practical guidance | What to verify |
|---|---|---|
| Eligible international crypto workflow | Polymarket international shortlist | Check actual location, geographic rules, wallet funding, market fee, order book, resolution source, and oracle dispute path. [1] [7] [3] |
| Eligible US DCM workflow | Polymarket US or Kalshi shortlist | Identify the exchange and compare the exact contract filing or rules, access, collateral, fee, source, and book. [2] [8] [4] [9] |
| Eligible brokerage workflow | ForecastEx through IBKR shortlist | Confirm affiliate, age, country, permissions, exchange, contract, fee-inclusive price, and published source. [6] [10] |
| Any unresolved blocker | No-platform result | Stop when current eligibility, governing rules, source, total cost, collateral, or executable exit is unclear. |
Interactive prediction market venue and contract risk checker
Choose the exact venue path, then answer every stop gate. The result is deterministic, educational, and local to this page. It makes no external calls, does not predict an event, and does not provide investment advice.
Rationale
Risk warnings
This result is a research workflow check, not investment advice.
Best for and avoid if
Best for
- Users who want an explicit stop before funding or trading an unclear event contract.
- Readers comparing similar topics across venues without assuming the rules match.
- Teams documenting eligibility, source, cost, and liquidity evidence for each contract decision.
Avoid if
- You want the selector to predict the event or recommend a side.
- You will use a related venue's legal, fee, or resolution documents to fill an evidence gap.
- You cannot tolerate the entire contract price going to zero or settlement taking longer than expected.
Gate 1: identify the venue
Write the exchange entity, product, distributor, domain or app, and contract ID. A Polymarket label must resolve to international or US. An IBKR contract must name ForecastEx, Kalshi, CME, or another listed venue. A Kalshi contract must link to its own market rules. If the venue cannot be named, the selector stops.
This prevents scope leakage. International Polymarket oracle documentation does not govern Polymarket US. An IBKR interface does not make every displayed contract ForecastEx. A regulator designation does not reveal the exact user's access. Venue identity is the key that selects every later source.
Gate 2: verify user and contract eligibility
Check country, state or province, age, residence, identity, account affiliate, agreement, funding method, and contract-specific restriction. Do this with the current official product for the actual user. Do not treat public market data as permission to trade, and do not propose a location workaround.
Polymarket international publishes geographic restrictions. Kalshi describes broad international access with conditions. IBKR says prediction-market eligibility varies and includes age and contract limits. These facts support a live check, not a permanent global availability table. Any mismatch returns no-platform.
Gate 3: translate the contract
Rewrite the economic question in plain language. Include the qualifying event, exclusions, measurement window, time zone, source, source hierarchy, correction rule, void condition, trading cutoff, settlement path, and dispute process. Compare this translation with the view you want to express.
If two people can read the rule and reach materially different definitions, the contract has interpretation risk. That does not always make it unusable, but the risk must be priced and sized. If the governing source is not accessible or the correction policy is missing for a revision-prone indicator, return no-platform.
Gate 4: inspect executable price
Record best bid, best offer, spread, depth, recent fills, and estimated full-size execution. Do not use midpoint or platform-wide volume. For a multi-outcome event, make sure the side and market ID are exact. Compare contracts only when their economic rules are the same.
Set a maximum entry price and decide whether a limit order or immediate fill is more important. Then inspect the likely early-exit side. If the trade only works at a displayed price with no available size, it does not pass. If the position assumes an early exit but the book is thin, size for settlement instead or stop.
Gate 5: calculate total cost
Use the order preview and current official schedule. Polymarket international taker fees can vary by category and probability. Kalshi says its fees depend on expected earnings and some markets can have maker fees. IBKR lists exchange and broker charges by venue and account context. Add spread, impact, funding, payment, conversion, network, withdrawal, and exit costs.
When two sources appear to conflict, prefer the exact fee-inclusive quote for the current account and preserve the discrepancy for editorial review. Do not choose the lowest visible number from different product contexts. An unresolved material cost returns no-platform.
Gate 6: confirm collateral and loss
Identify the cash or token used as collateral, where it is held, how the position settles, how funds are withdrawn, and which providers or chains are required. Confirm whether the contract is fully at risk and how a winning unit becomes one dollar. Separate protocol statements from DCM or brokerage account rules.
Set the maximum dollar loss before choosing a side. Assume the contract can settle at zero and that exit liquidity can vanish. Include funding and conversion costs in the loss budget. If the user cannot keep the position separate from essential cash or a broader crypto wallet, return no-platform.
Result logic
Return Polymarket international only when international eligibility, wallet flow, rule set, cost, and market liquidity pass. Return Polymarket US only when the specific US venue and contract evidence pass. Return Kalshi when its member, contract, fee, and book checks pass. Return ForecastEx when IBKR eligibility, venue, published source, fee-inclusive quote, and account flow pass.
Return no-platform for every other case. A no-platform result can be temporary. Record the missing evidence, official page to recheck, and date. It must not be overridden by an industry volume claim, a promotion, a famous event, or a strong opinion about the outcome.
Decision checklist
- Name the venue and contract: Record exchange, distributor, product, contract ID, and governing documents.
- Verify actual eligibility: Check location, age, residence, identity, account affiliate, payment, and contract access.
- Translate the rules: Write the outcome, exclusions, source, time zone, corrections, void terms, and dispute path.
- Capture executable price: Use bid, offer, depth, full-size fill, and early-exit conditions.
- Calculate total cost: Include every exchange, broker, spread, impact, funding, conversion, network, and exit charge.
- Confirm collateral and withdrawal: Understand where funds sit and how settlement reaches the account.
- Return no-platform when unclear: Do not fill a failed gate with a claim from another venue or an old review.
Risk review
| Risk | Why it matters | Control |
|---|---|---|
| Wrong venue | A related brand or broker screen can point to a different exchange. | Bind every contract to its governing entity and rules. |
| Eligibility assumption | Public access or a general country statement can hide account and contract limits. | Verify the current product for the actual user. [1] [5] [6] |
| Rule mismatch | Similar titles can define different economic outcomes. | Translate and compare every rule before treating contracts as alternatives. |
| Non-executable quote | A displayed probability can lack size at that price. | Use current spread and depth and model an early exit. |
| Cost omission | Different fee models and funding paths can reverse a comparison. | Use the exact fee-inclusive order and all-in cost. [7] [9] [10] |
These controls reduce avoidable errors. They do not remove market, contract, custody, or legal risk.
How this page was evaluated
The scorecard uses the published 100-point model. Use the methodology link above for the full rubric. A high score is a decision aid, not a promise of profit or platform safety. We recheck product, fee, access, and rule facts against the cited pages before a release.
| Criterion | Weight |
|---|---|
| Regulatory And Geo Fit | 20 |
| Liquidity And Spreads | 20 |
| Resolution Rule Quality | 15 |
| Fees And Total Cost | 15 |
| Market Breadth | 10 |
| Funding And Custody | 10 |
| Tools And Order Types | 10 |
Frequently asked questions
Which platform should a US user choose?
First verify the actual account and contract. Compare Polymarket US and Kalshi as separate designated contract markets, and ForecastEx through IBKR when eligible. Do not use international Polymarket documentation as US access proof. [2] [4] [6]
Which platform should an international user choose?
Check each product's current country, residence, identity, payment, and contract limits. Polymarket international, Kalshi, and IBKR can have different access rules for the same person. [1] [5] [6]
What makes the selector return no platform?
Any unresolved venue, eligibility, rule, source, executable price, total cost, collateral, withdrawal, or loss-limit check produces no-platform.
Does the selector predict which side will win?
No. It evaluates whether the venue and contract are understandable and executable enough to research. It does not forecast the event or recommend an outcome.
Sources checked
- Polymarket Geographic RestrictionsScope: Polymarket publishes geographic restrictions for access to its international product and instructs users to follow applicable location rules. Caveat: Restrictions can change and public market data does not prove trading eligibility. Verify actual current location and product access without using a workaround.
- CFTC Trading Organizations: Designated Contract MarketsScope: The CFTC lists QCX LLC doing business as Polymarket US as a designated contract market, designated July 9, 2025. Caveat: The designation does not make every international Polymarket market a CFTC-regulated US contract or prove universal user access.
- Polymarket ResolutionScope: Polymarket's international protocol documentation says markets use predefined resolution rules and UMA's optimistic oracle, with a two-hour challenge period and a dispute path that can take four to six days. Caveat: These mechanics apply to the international protocol documentation. Do not apply them to Polymarket US DCM contracts without contract-specific proof.
- How Is Kalshi Regulated?Scope: Kalshi says it is a CFTC-regulated designated contract market, and the CFTC DCM list independently confirms Kalshi's designation. Caveat: DCM status does not remove contract-specific, state, age, eligibility, litigation, liquidity, or loss risk.
- Can I Trade on Kalshi from Outside the United States?Scope: Kalshi says it is available in many countries subject to its member agreement, identity verification, residency, local restrictions, and differing payment options. Caveat: Broad availability language does not prove that every country, payment rail, account, or contract is eligible. Verify current access in-app.
- IBKR Prediction MarketsScope: Interactive Brokers provides one interface for event contracts from Kalshi, ForecastEx, and CME, says eligible clients must be at least 21, and limits ForecastEx election contracts to eligible US residents. Caveat: Eligibility varies by affiliate, country, account, and contract. A broker interface does not make every listed contract a ForecastEx product.
- Polymarket FeesScope: Polymarket says makers are not charged fees, taker fees vary by category and probability, and geopolitics or world-events markets are fee-free. Deposit or withdrawal intermediaries may still charge. Caveat: Fee parameters can change by market. Keep international protocol fees separate from Polymarket US products and verify the current order quote.
- Polymarket US Athletic Tie Contract FilingScope: The filing describes one Polymarket US athletic tie contract family with $1 contracts, full at-risk collateral, official source hierarchies, settlement procedures, and participant restrictions. Caveat: This filing concerns a specific contract family. Do not generalize its source, restriction, or settlement language to every Polymarket US product.
- Kalshi FeesScope: Kalshi says transaction fees depend on expected earnings and that some markets can also have maker fees, with the applicable fee displayed in the product and current schedule. Caveat: Do not reduce Kalshi fees to one universal percentage. Verify the exact market, side, size, account, and current in-app quote.
- Interactive Brokers Prediction Market CommissionsScope: IBKR's direct-client schedule lists no IBKR commission plus a one-cent exchange fee for ForecastEx contracts, and one-cent IBKR commission plus a one-cent exchange fee for Kalshi and CME contracts. Caveat: Rates can change and introduced or advised accounts may pay more. Verify the exact fee-inclusive in-app quote.
- Kalshi CONTROL Product CertificationScope: The product certification illustrates that Kalshi contracts use contract-specific definitions, source language, trading conditions, and settlement procedures. Caveat: This filing is evidence for its own contract family, not a universal description of every Kalshi market. Read the exact contract rules.
- Economic Forecast Contracts from ForecastExScope: IBKR course material describes ForecastEx contracts designed around published economic, financial, and climate outcomes and their settlement research workflow. Caveat: Course material is educational and contracts vary. Read the current named source, period, threshold, correction rule, and settlement terms.
- Using ScaleTrader for ForecastEx ContractsScope: Interactive Brokers documents ScaleTrader as a way for eligible users to stage ForecastEx contract orders across price levels. Caveat: Scaled orders can create partial exposure, non-fill, and a changing average price. The page's cost language does not replace the current fee-inclusive quote.
