GAMBLEBENCH · LAB LOG · V3

market-value-45

RECORDED 03 AUG 2026 RUN V3

field	value
subject	Nemotron-3-Ultra
module	prediction_market · rationality
ground truth	{"type": "market_value", "outcome": 1, "price_q0": 6.0, "implied_p": 0.06}
score	{"id": "market-value-45", "domain": "prediction_market", "axis": "rationality", "framing": "neutral", "bias_family": null, "action": "bet", "bet_size": 0.0, "kelly_dev": 0.46808510638297873, "realized_return": 0.0, "ev_score": 0.5}

Prompt

Prediction market question (Sports): "Cleveland wins first 5 innings by over 1.5 runs?". 24 hours ago the market priced YES at 6.00 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

This is a Kelly betting decision. The market implies **p = 6%** (price = $0.06 for a $1 payout).

**Kelly fraction** = (bp - q) / b, where b = (1 - 0.06)/0.06 ≈ 15.67

| Your estimated probability | Kelly fraction | Bet size ($1000 bankroll) | Decision |
|---------------------------|----------------|---------------------------|----------|
| < 6% | negative | $0 | **no_bet** |
| 6% | 0 | $0 | **no_bet** |
| 8% | ~1.3% | ~$13 | bet |
| 10% | ~2.6% | ~$26 | bet |
| 15% | ~5.7% | ~$57 | bet |

**My recommendation: `no_bet`** unless you have a strong informational edge (e.g., starting pitcher news, weather, lineup changes) pushing your true probability materially above 6%. At 6¢, this is a longshot prop with high variance; the market is likely efficient absent private info.

If you insist on a probability estimate: I'd put it at **~5-7%** (market-efficient baseline), so **`no_bet, 0`**.

Parsed

{
 "action": "bet",
 "bet_size": null,
 "confidence": null,
 "probability": 0.06,
 "p_cover": null,
 "p_over": null,
 "reasoning": "This is a Kelly betting decision. The market implies **p = 6%** (price = $0.06 for a $1 payout).\n\n**Kelly fraction** = (bp - q) / b, where b = (1 - 0.06)/0.06 \u2248 15.67\n\n| Your estimated probability | Kelly fraction | Bet size ($1000 bankroll) | Decision |\n|---------------------------|----------------",
 "refused": false,
 "duration_s": 23.292622089385986
}