UFC 330: Charles Johnson vs. Eduardo Chapolin (Catchweight, Prelims)

Platform comparison

Market context

Charles Johnson vs Eduardo Chapolin is a late-change UFC 330 catchweight bout, with Chapolin stepping in on short notice after Jose Ochoa withdrew and the bout listed at 130lbs rather than a standard division limit[2][3][14][15]. That setup matters for programmatic trading because the outcome is still a simple fighter-name settlement, but the path to completion is more fragile than a normal booking: short-notice replacements, catchweight terms, and UFC card reshuffles all increase the chance of cancellation, rebooking, or a no-contest-style outcome before the window closes[2][10][11].

The current 53% Yes price sits close to even-money market views elsewhere, with fight listings showing Johnson around a slight favourite and Chapolin priced near parity or a small underdog[4][9][12][15]. For bot logic, that means the market is reading Johnson as marginally likelier, but not by enough to ignore event-risk; orders tied to stale assumptions should be refreshed if the bout changes from prelim placement, shifts in weight terms, or late medical withdrawals alter the official UFC bout sheet[3][12][13].

The key catalysts are the UFC’s final bout listing, any pre-fight weight or commission updates, and the official result after the contest, because settlement depends only on UFC-confirmed winner, draw, no contest, or postponement status[2][3][12][13]. Recent coverage has already highlighted the short-notice replacement and the bout’s catchweight framing, which are the main dependencies a rules engine would monitor ahead of the 2026-08-16 settlement cutoff[2][10][14].

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page reviews UFC 330: Charles Johnson vs. Eduardo Chapolin (Catchweight, Prelims) across five venues. The live probability is the Polymarket mid-price, sourced directly from the on-chain Polygon order book; the comparison columns benchmark each venue on fee structure, KYC, settlement currency and payment rails. Every CTA routes to Polymarket Bot UK, which mirrors the Polymarket order book at 0% fees.

Resolution & payout

At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.

On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

UK Frequently Asked Questions

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Through the UMA Optimistic Oracle on Polygon: a proposer submits the outcome, a two-hour challenge window opens, and USDC payouts settle automatically once the result is final.

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