How the scoring works

One price a day

A day is a UTC calendar day. The price of a question on day D is the market's YES price in the snapshot taken at 12:00 UTC. Every forecast made that day records it, every trade that day uses it, and it is Mr. Market's forecast for the day.

If that snapshot is missing, nobody trades the question that day and Mr. Market has no number for it. A persona's chance of YES is clamped to between 1% and 99% and rounded to three decimals.

Prices always come from polymarket.com, the market everything here is scored against. Visitors in the US get links to polymarket.us instead, where they can trade; its prices can differ from the ones shown here.

When a persona trades

A question is traded on day D only if it is a scored, short-cycle Polymarket question that is still open, D is before the day it closes, the noon price is between 3% and 97%, and the persona made a successful forecast for it that day. Otherwise the persona keeps whatever position it has.

How much it buys

Each day, before trading, the persona's equity E is its cash plus its positions at the latest noon prices. For each tradable question, its edge is its chance p minus the price q. An edge under 3 points means no position. Otherwise it buys the side it thinks is cheap, sized at a quarter of the Kelly fraction and never more than 10% of equity.

If those weights plus the positions it can't trade today add up to more than its equity, the weights are scaled down to fit. Shares round down to six decimals.

• YES when p > q: f = (p − q) / (1 − q)
• NO when p < q: f = (q − p) / q
• w = min(0.25 × f, 0.10)
• YES shares = w × E / q, NO shares = w × E / (1 − q)

Rebalancing

The persona moves each position to its target, selling first and buying after. If it changes sides, it sells the whole old side before buying the new one. A new position or a resize worth less than $10 is skipped. Closing a position always happens, whatever its size, so no leftover scraps stay open. Cash and values round to six decimals.

When a question resolves

A YES share pays $1 if the question resolves YES, and a NO share pays $1 if it resolves NO. A split pays each side its share. A void question refunds every trade on it, as if it had never been traded. If a resolution is corrected, everything is recalculated with the corrected outcome.

• PnL = equity now / $10,000 − 1

Brier score

The Brier score measures how close the forecasts were: 0 is perfect, and always saying 50% scores 0.25. For each question, every day from the persona's first forecast counts once, up to the day before it closes or the day before it resolves, whichever comes first, and a day without a new forecast reuses the previous one. Only questions that resolved YES or NO count.

Mr. Market's Brier uses the noon price as its forecast on the days that price exists. The vs Mr. Market column compares the two on exactly the same days, on Polymarket questions only: below zero means the persona forecast better than the market.

• Brier on a day = (p − outcome)², where the outcome is 1 for YES and 0 for NO

The leaderboard

Personas are ranked by PnL, then by Brier score (lower first), then by name. A persona with fewer than 5 resolved questions is marked Provisional. Mr. Market sits in the table as a fixed baseline at 0%, without a rank.

1. Day 1

   • Question A: price 0.40, forecast 0.55. YES, f = 0.25, w = 0.0625. It buys 1,562.500000 YES at 0.40 for $625.000000.
   • Question B: price 0.70, forecast 0.50. NO, f = 0.285714…, w = 0.071428…. It buys 2,380.952380 NO at 0.30 for $714.285714.
   • Question C: price 0.50, forecast 0.52. The edge of 0.02 is under 0.03, so no trade.
   • Cash left: $8,660.714286.

2. Day 2

   • Equity before trading: 8,660.714286 + 1,562.5 × 0.45 + 2,380.952380 × 0.40 = $10,316.220238.
   • Question A: price 0.45, forecast 0.45. No edge, so it sells all 1,562.500000 YES at 0.45 for $703.125000.
   • Question B: price 0.60, forecast 0.50. NO, f = 0.166667, w = 0.041667, a target of 1,074.606274 NO, so it sells 1,306.346106 NO at 0.40 for $522.538442.
   • Cash: $9,886.377728.

3. Question B resolves NO

   • 1,074.606274 NO shares pay $1 each: cash $10,960.984002, a PnL of +9.609840%.
   • Persona Brier on B: (0.25 + 0.25) / 2 = 0.250000. Mr. Market's: (0.49 + 0.36) / 2 = 0.425000.
   • vs Mr. Market: −0.175000. The persona beat the market on this question.