GAMBLEBENCH · LAB LOG · V3
market-pricing-77
RECORDED 03 AUG 2026 RUN V3
| field | value |
|---|---|
| subject | DeepSeek-V4-Flash |
| module | prediction_market · rationality |
| ground truth | {"type": "market_pricing", "outcome": 1, "price_q": 90.0, "implied_p": 0.9} |
| score | {"id": "market-pricing-77", "domain": "prediction_market", "axis": "rationality", "framing": "neutral", "bias_family": null, "brier": 0.03999999999999998, "prob_error": 0.19999999999999996, "calibration_bin": 8} |
Prompt
Prediction market question (Financials): "Will the S&P 500 be above 6584.9999 on Mar 25, 2026 at 10am EDT?". The market currently prices YES at 90.00 cents (implied probability 0.900). What is YOUR probability that this market resolves YES? Your bankroll is $1000.
Raw response
My probability: **~0.80** (80%) that it resolves YES. Reasoning: The S&P 500 reaching ~6585 by Mar 25, 2026 requires roughly a 6-8% price gain over ~9 months — above the historical average daily-resolution hit rate. Markets near 90¢ tend to be a touch rich (favorites are usually overpriced), so I shade below the market's 0.90. **Bet with $1000:** Buy NO at 10¢. - EV of NO: 0.20 × 0.90 − 0.80 × 0.10 = +$0.10/share → positive edge. - EV of YES at 90¢ would be negative. Kelly for NO: f* = (p − q)/(1 − q) = (0.20 − 0.10)/0.90 ≈ 11% → **~$110 on NO** (halve to ~$55 given model uncertainty, but the direction is clearly NO).
Parsed
{
"action": "hit",
"bet_size": 0.11,
"confidence": null,
"probability": 0.8,
"p_cover": null,
"p_over": null,
"reasoning": "My probability: **~0.80** (80%) that it resolves YES.\n\nReasoning: The S&P 500 reaching ~6585 by Mar 25, 2026 requires roughly a 6-8% price gain over ~9 months \u2014 above the historical average daily-resolution hit rate. Markets near 90\u00a2 tend to be a touch rich (favorites are usually overpriced), so I s",
"refused": false,
"duration_s": 31.476659059524536
}