National Bank Open: Adam Walton vs Jenson Brooksby

Platform comparison

Market context

Adam Walton is due to play Jenson Brooksby in the National Bank Open, and the market’s 25% yes price implies a much weaker chance for Walton than the tennis books currently show. Recent bookmaker screens put Brooksby around 1.66-1.73 decimal and Walton around 2.10-2.20, which translates to roughly a 58-61% Brooksby chance and 39-48% for Walton before margin, so Polymarket’s crowd price is materially more bearish on Walton than the mainstream market. [1][7]

That gap matters because this is a small-sample, schedule-sensitive first-round style match where even modest information can move prices quickly. Tennis.com’s projection has Brooksby ahead at 55% to 45%, and Dimers is similar at 54.7% to 45.3%, while Tennis Tonic also lands on Brooksby as the pick; the current crowd figure therefore sits below most comparable models and below the average bookmaker line. [9][11][3] For comparison across platforms, Betfair’s decimal pricing is closest to the broader bookmaker consensus, while Polymarket and Kalshi-style markets surface the outcome as an implied probability; Smarkets would typically quote a similar market with commission rather than an outright overround, but exact take rates and access depend on account jurisdiction and KYC status. [1]

For traders, the main catalysts are whether the match starts on schedule, whether there is a late withdrawal, and whether a postponement pushes it beyond the seven-day settlement grace period, because that would force the market to 50-50 rather than a winner call. The match page shows it as a live scheduled contest, but tennis draws and session timing can still shift quickly at Masters 1000 events, so official order-of-play updates and any withdrawal news are the key triggers rather than headline tournament odds alone. [1][6][10]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page compares National Bank Open: Adam Walton vs Jenson Brooksby specifically across Polymarket, Kalshi, Betfair Exchange and Smarkets. The live probability is the Polymarket mid; the comparison columns summarise each venue's fee structure, KYC, settlement currency and payment rails. Every CTA routes to Kalshi Alternative UK, which mirrors the Polymarket order book at 0% fees.

Resolution & payout

Settlement is the biggest difference between the four platforms: Polymarket on-chain in USDC (instant), Kalshi USD via CFTC (T+1), Betfair and Smarkets in local currency via bank withdrawal (T+1 to T+3). On-chain settlement clears in minutes — the fastest payout path of the four.

FAQ

Polymarket vs Kalshi — which is better?

Depends on your location. Kalshi is CFTC-regulated, US-only with full KYC. Polymarket is global, on-chain, no KYC up to $1,500. Polymarket has ~10x higher liquidity but higher regulatory risk.

What does Polymarket cost vs Kalshi?

Polymarket: 0% fees, only Polygon network costs (~$0.01/trade). Kalshi: up to 7% per trade plus spread. For high-frequency traders, Polymarket is dramatically cheaper.

Which platform has the deepest liquidity?

Polymarket — by a wide margin. Top markets reach $50-500M volume, Kalshi ~$200M cumulative, Betfair similar. Deeper liquidity means your trade moves the quote less.

Which platform is accessible globally?

Polymarket is geo-blocked in the US/UK/EU. Kalshi is US-only. Betfair and Smarkets are UK-restricted. Kalshi Alternative UK has a different geo footprint and routes to Polymarket's order book at 0% fees.

Are all these platforms regulated?

No. Kalshi is CFTC-regulated (US). Betfair and Smarkets are UK Gambling Commission licensed. Polymarket operates without explicit regulation — a different risk profile than a regulated sportsbook.