2026 Seoul Mayoral Election: Margin of Victory

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Market context

Seoul will elect a new mayor on 3 June 2026, with the margin of victory between the top two candidates determining the resolution. The margin is calculated as the absolute percentage-point difference in valid votes cast, excluding spoiled ballots and minor candidates. This metric captures competitive intensity rather than absolute vote share, making it sensitive to both turnout patterns and candidate consolidation in what remains South Korea's most politically contested metropolitan race.

Historical Seoul mayoral contests show margins typically ranging from 3 to 8 percentage points in recent cycles, though the 2014 election saw a tighter 2.9-point result. The current 0% probability assignment suggests either extreme confidence in a specific outcome or insufficient market liquidity at present. Comparable races—including the 2022 presidential election (0.73-point margin) and recent provincial contests—indicate that South Korean urban elections can produce surprisingly narrow results when opposition parties field competitive candidates. The ruling Democratic Party and opposition People Power Party both maintain significant Seoul voter bases, making prediction difficult without candidate announcements.

Key catalysts include formal candidate registration (expected early 2026), polling releases from major Korean media outlets, and any shifts in national political dynamics affecting local races. The Korea Elections Commission will publish detailed vote tallies within days of polling, with no recount threshold typically triggered unless margins fall below 0.5 points. Traders should monitor announcements from potential candidates including incumbent-aligned figures and opposition nominees, as candidate quality and name recognition historically shift margins by 2–4 points in Seoul races. The settlement window closes at midnight UTC on 3 June 2026, coinciding with Seoul local time election day.

Methodology

We track 2026 Seoul Mayoral Election: Margin of Victory on the five venues with material liquidity for prediction markets. Live odds come from the Polymarket Polygon order book — the only source that ships real-time data under an open licence. For Kalshi, Betfair and Manifold we list platform attributes (fee, KYC, settlement, payment) instead of fabricated odds, because their APIs use non-comparable contract definitions.

Resolution & payout

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

FAQ

Where can I trade this market with the lowest fees?

On Polymarket KYC UK, which mirrors the Polymarket order book at 0% fees. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

Is this market available outside the US?

Polymarket KYC UK is available in most jurisdictions where Polymarket isn't directly accessible. Polymarket itself is geo-blocked in the US/UK/EU. Always check local regulations.

What does it cost to trade on Polymarket KYC UK?

Zero. Polymarket KYC UK routes every order to the live Polymarket order book; the only cost is the Polygon network fee, typically under $0.01 per transaction.

How fast are USDC deposits?

Polygon credits deposits after 12 confirmations — usually under 30 seconds. Withdrawals follow the same path and land back in your wallet within minutes.

How reliable are the quoted odds?

The YES/NO percentages are the live mid-prices of the Polymarket order book. On deep markets they move every few seconds; on thinner ones you'll see short plateaus.