National Bank Open: Marta Kostyuk vs Katherine Sebov

Platform comparison

Market context

National Bank Open: Marta Kostyuk vs Katherine Sebov — current market-implied probability: 100%. This market refers to the tennis match between Marta Kostyuk and Katherine Sebov in the National Bank Open, originally scheduled for August 4, 2026 at 2:00PM ET. This market will resolve to 'Marta Ko…

Methodology

This overview of National Bank Open: Marta Kostyuk vs Katherine Sebov reviews the four comparable platforms from a regulatory perspective: which is accessible in your jurisdiction, where KYC kicks in, how the platform is classified by your country of residence. Live probability is the Polymarket mid; comparison columns show regulatory status, KYC thresholds and settlement options for each platform.

Resolution & payout

On Polymarket, resolution runs on-chain via UMA Optimistic Oracle. USDC payout is instant and automatic, with no KYC. Tax treatment depends on your jurisdiction — in the US, gains are usually ordinary income; in the UK, often capital gains. Consult a tax professional for your situation.

FAQ

How are winnings taxed?

Tax treatment varies by jurisdiction. In most countries, prediction market gains are treated as ordinary income or capital gains. We cannot provide tax advice — consult a tax professional for your specific situation.

What happens during a tax audit?

You're responsible for documenting your trades. Polymarket Legal UK exports a full transaction history (CSV/PDF) for tax reporting. In an audit you'll need to present these documents.

Are prediction markets gambling?

Legally unclear in most jurisdictions. Some interpretations classify them as wagering (gambling regulation applies), others as derivatives (financial regulation applies). There's no global precedent specifically for on-chain prediction markets.

Is there a withdrawal cap?

No platform-side cap. You can withdraw any amount provided KYC is complete. SEPA bank withdrawals over €15,000 trigger additional anti-money-laundering checks (statutory obligation for all platforms).

What if regulation changes?

If regulation changes in your jurisdiction (e.g. prediction markets are banned), Polymarket Legal UK would geo-block the affected region and continue processing withdrawals. Your funds remain withdrawable at any time.