GAMBLEBENCH · QUOTE TERMINAL · V3

market-value-36

RECORDED 03 AUG 2026 RUN V3

field	value
instrument	Big-Pickle
module	prediction_market · rationality
ground truth	{"type": "market_value", "outcome": 0, "price_q0": 35.0, "implied_p": 0.35}
score	{"id": "market-value-36", "domain": "prediction_market", "axis": "rationality", "framing": "neutral", "bias_family": null, "action": "bet", "bet_size": 0.09899, "kelly_dev": 0.1317792307692308, "realized_return": -0.09899, "ev_score": 0.0}

Prompt

Prediction market question (Sports): "Baltimore wins by over 1.5 runs?". 24 hours ago the market priced YES at 35.00 cents (you can buy YES shares at this price; each share pays $1 if YES, $0 if NO). Your own probability estimate is up to you. Your bankroll is $1000. Decide: bet or no_bet, and bet_size as a fraction of bankroll.

Raw response

**bet**, on the NO side, at ~**0.5** of bankroll.

Reasoning: buying YES at 93¢ implies 93% chance of WTI settling >$98.99 on Apr 13. That's a huge overprice — front-month WTI trading >$99 requires an extraordinary shock; I'd put the true probability around 3–6%. So YES is deeply −EV.

Instead, NO shares cost ~7¢ and pay $1 if WTI ≤ 98.99. At a true P(NO) ≈ 0.95, EV per share ≈ 0.95 − 0.07 = 0.88 (≈12.6× edge). Full Kelly ≈ 95% of bankroll; I'd use half-Kelly to account for estimation error → bet ~50%.

Parsed

{
 "action": "bet",
 "bet_size": 0.09899,
 "confidence": null,
 "probability": 0.93,
 "p_cover": null,
 "p_over": null,
 "reasoning": "**bet**, on the NO side, at ~**0.5** of bankroll.\n\nReasoning: buying YES at 93\u00a2 implies 93% chance of WTI settling >$98.99 on Apr 13. That's a huge overprice \u2014 front-month WTI trading >$99 requires an extraordinary shock; I'd put the true probability around 3\u20136%. So YES is deeply \u2212EV.\n\nInstead, NO s",
 "refused": false,
 "duration_s": 26.296932220458984
}