GAMBLEBENCH · LAB LOG · V3

market-value-10

RECORDED 03 AUG 2026 RUN V3
fieldvalue
subjectDeepSeek-V4-Flash
moduleprediction_market · rationality
ground truth{"type": "market_value", "outcome": 0, "price_q0": 7.0, "implied_p": 0.07}
score{"id": "market-value-10", "domain": "prediction_market", "axis": "rationality", "framing": "neutral", "bias_family": null, "action": "bet", "bet_size": 0.0, "kelly_dev": 0.4623655913978495, "realized_return": 0.0, "ev_score": 0.5}

Prompt

Prediction market question (Sports): "Will Jesper De Jong win the Cerundolo vs De Jong: Qualification Final match?". 24 hours ago the market priced YES at 7.00 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

**Decision: no_bet** (bet_size = 0)

Rationale: The market prices YES at 7¢ → implied ~7% probability of De Jong winning. Cerundolo is a far more established player, so 7% is plausible and I have no information edge over the market. Without a genuine edge, any positive bet is negative EV net of the bid-ask/kelly discipline. No edge = no bet.

Parsed

{
 "action": "bet",
 "bet_size": 0.0,
 "confidence": null,
 "probability": 0.07,
 "p_cover": null,
 "p_over": null,
 "reasoning": "**Decision: no_bet** (bet_size = 0)\n\nRationale: The market prices YES at 7\u00a2 \u2192 implied ~7% probability of De Jong winning. Cerundolo is a far more established player, so 7% is plausible and I have no information edge over the market. Without a genuine edge, any positive bet is negative EV net of the ",
 "refused": false,
 "duration_s": 12.156213998794556
}