National Bank Open: Ann Li vs Elena Rybakina

Platform comparison

Market context

Elena Rybakina’s match with Ann Li at the National Bank Open is priced as a one-sided contest across conventional books, with Rybakina around 1.14-1.16 decimal and Li near 5.0-5.7, which implies roughly 86-88% for Rybakina before any margin, versus a low-teens or low-20s chance for Li depending on the source.[2][5][11] That makes Polymarket’s current 0% YES especially notable: it is far below the bookmaker-implied range and also below model-based estimates such as Dimers’ 77.5% for Rybakina and Tennis Tonic’s straight Rybakina call.[6][1] On Kalshi, the same kind of contract is quoted in cents rather than percentages, so a 77% view would typically sit near 77¢/23¢; on Polymarket, crowd-implied probability is shown directly, while Betfair and Smarkets usually translate the same view into decimal odds minus commission, so fees matter more when comparing thin edges.[14][2]

For context, markets like this usually swing on whether the favourite is confirmed fit, whether the match starts on time, and whether the event is played through rather than voided or settled at 50-50 under the rules. TennisTemple and other live scoreboards list the fixture in Toronto with Rybakina seeded far higher in the rankings, which is consistent with the market’s heavy favourite pricing.[2][8] The main catalyst is simple: official draw-order and court-schedule updates, plus any late withdrawal, retirement, or weather delay that could push the match beyond the seven-day settlement window. In practice, that matters more on Polymarket and Kalshi than on Betfair or Smarkets, where traders may care about whether commission and KYC access change the effective price they can actually capture.[2][4][12]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We read National Bank Open: Ann Li vs Elena Rybakina from four platform perspectives: Polymarket (on-chain CLOB), Kalshi (CFTC-regulated exchange), Betfair Exchange (sports book exchange), Smarkets (peer-to-peer betting exchange). Polymarket's live mid is the canonical probability; the side-by-side columns benchmark fees, KYC, settlement currency and deposit rails so you can choose the venue that fits your jurisdiction and trade size.

Resolution & payout

Polymarket settles via UMA Optimistic Oracle on Polygon. A proposer posts the outcome with a bond, the two-hour window runs, then the smart contract pays USDC.

Kalshi settles USD through the CFTC-regulated clearinghouse — the cleanest variant, with heavier KYC. Betfair Exchange settles in account currency (GBP/EUR), net of 2-5% commission. Smarkets follows the same model as Betfair with a lower default 2% commission.

UK Frequently Asked Questions

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.

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.

Is Betfair a Polymarket alternative?

Only partially. Betfair Exchange is UK-focused with a sports-betting emphasis; they have politics markets but with thinner liquidity than Polymarket. Settlement in GBP/EUR, 2-5% commission on winnings.

Polymarket vs Betfair Exchange: which is better for UK prediction trading?

Betfair Exchange offers UKGC regulation, GBP settlement, and potentially tax-free winnings — but focuses on sports and politics only. Polymarket has deeper liquidity, 0% platform fee, global event coverage, and crypto/geopolitical markets Betfair doesn't offer. For UK traders: Betfair for regulated GBP sports markets; Polymarket for broader, global prediction events.

Is Kalshi available in the UK?

Kalshi is a US CFTC-regulated prediction exchange. UK residents can create accounts but must use USD and US payment methods. Kalshi's product range overlaps with Polymarket but with lower liquidity on most contracts. For UK traders, Polymarket typically offers better prices due to higher global volume.