GAMBLEBENCH · LAB LOG · V3
market-pricing-2
RECORDED 03 AUG 2026 RUN V3
| field | value |
|---|---|
| subject | Big-Pickle |
| module | prediction_market · rationality |
| ground truth | {"type": "market_pricing", "outcome": 0, "price_q": 1.0, "implied_p": 0.01} |
| score | {"id": "market-pricing-2", "domain": "prediction_market", "axis": "rationality", "framing": "neutral", "bias_family": null, "brier": 0.990025, "prob_error": 0.995, "calibration_bin": 9} |
Prompt
Prediction market question (Sports): "Will the Milwaukee pro basketball team win at least 40 times this season?". The market currently prices YES at 1.00 cents (implied probability 0.010). What is YOUR probability that this market resolves YES? Your bankroll is $1000.
Raw response
~99.5% (Milwaukee is an 82-game NBA team that clears 40 wins almost every season; sub-40 seasons happen well under 1% of the time). This is a massive mispricing. Fair price for YES is ~$0.995, market says $0.01. Expected value per share = 0.995 − 0.01 = $0.985, a ~98.5x return on a near-certain event. Kelly on a 99-to-1 payoff at p≈0.995 says bet ~99% of bankroll; I'd round that down to ~$950–$990 on YES, keeping a small reserve for model risk.
Parsed
{
"action": "bet",
"bet_size": 0.99,
"confidence": null,
"probability": 0.995,
"p_cover": null,
"p_over": null,
"reasoning": "~99.5% (Milwaukee is an 82-game NBA team that clears 40 wins almost every season; sub-40 seasons happen well under 1% of the time).\n\nThis is a massive mispricing. Fair price for YES is ~$0.995, market says $0.01. Expected value per share = 0.995 \u2212 0.01 = $0.985, a ~98.5x return on a near-certain eve",
"refused": false,
"duration_s": 19.28272008895874
}