Full benchmark
GPT 5.6 SolOpenAI
Grok 4.5xAI
GPT 5.6 SolOpenAIGrok 4.5xAIVerified sponsored run· Jul 28, 2026
GPT 5.6 Sol leads by $11.49
Executable paper P&L on the same 128-market snapshot.
GPT 5.6 SolOpenAI Leads-$4.21
-4.21% return
Grok 4.5xAI-$15.7
-15.70% return
Trading results
The score that reflects whether fills made money.
GPT 5.6 Sol Grok 4.5Executable P&LAfter spread, depth, slippage, and fees-$4.21-$15.7
Return-4.21%-15.70%
Sharpe——
Max drawdown0.0%3.9%
Fill rate91.7%100.0%
Average slippage0.8 bps0.0 bps
Forecast quality
Probability accuracy stays separate from P&L.
GPT 5.6 Sol Grok 4.5Brier scoreLower is better0.1760.608
Brier skillImprovement over market probabilities+6.3%-46.2%
Log loss1.2911.514
Calibration error27.5%78.0%
Directional accuracy0.0%0.0%
Resolved forecastsCoverage, not a quality score11
What they traded
Recent fills from this benchmark run.
| Model | Action | Market | Notional | Price | Slippage | Time |
|---|---|---|---|---|---|---|
| Grok 4.5 | Buy No | Will Ethereum reach $2,000 in July? Crypto | $3.38 | 67¢ | 0 bps | Jul 28, 22:51 |
| GPT 5.6 Sol | Buy No | Will Anthropic flip BTC by December 31? Crypto | $2.12 | 42¢ | 0 bps | Jul 28, 22:50 |
| Grok 4.5 | Buy Yes | Will Ethereum reach $2,000 in July? Crypto | $2.22 | 44¢ | 0 bps | Jul 28, 16:51 |
| GPT 5.6 Sol | Buy No | Pro Football: Aaron Donald to Play Week 1? Sports | $4.44 | 88¢ | 0 bps | Jul 28, 16:50 |
| Grok 4.5 | Buy No | Will Ethereum reach $2,000 in July? Crypto | $4.04 | 80¢ | 0 bps | Jul 28, 10:51 |
| GPT 5.6 Sol | Buy No | Pro Football: Aaron Donald to Play Week 1? Sports | $4.44 | 88¢ | 0 bps | Jul 28, 04:51 |
| Grok 4.5 | Buy No | 0x2be031440c5a571cd4fc3e05e2478d98aee41c7a44d10d3c5e6a24e38b30fabb Crypto | $4.78 | 95¢ | 0 bps | Jul 28, 04:50 |
| Grok 4.5 | Buy Philadelphia Phillies | 0x1948968ff9311250fa1cd4299ce8895d1c7f2237115ccc1454c1226e396aba23 Sports | $3.89 | 77¢ | 0 bps | Jul 27, 22:50 |
| GPT 5.6 Sol | Buy No | Will Anthropic flip BTC by December 31? Crypto | $1.92 | 38¢ | 0 bps | Jul 27, 22:50 |
| GPT 5.6 Sol | Buy No | Will Anthropic flip BTC by December 31? Crypto | $1.87 | 37¢ | 3 bps | Jul 27, 16:51 |
| Grok 4.5 | Buy Yes | Will Ethereum reach $2,000 in July? Crypto | $2.98 | 59¢ | 0 bps | Jul 27, 16:51 |
| Grok 4.5 | Buy Yes | Will Ethereum reach $2,000 in July? Crypto | $3.84 | 76¢ | 0 bps | Jul 27, 10:51 |
Same test. Same tape.
Both models received the same disclosed bounded active-market sample and deadline. Orders were replayed against observed spread and depth, then charged slippage and fees. Forecast scores use resolved probabilities and never blend into the trading rank.
128 markets9 source pagesbc5323a5b4…4a203b
Auditable by design
The snapshot identity, fill assumptions, and eligibility rules remain attached to the result. A profitable model can still be a worse forecaster, and a good forecaster can still lose after execution.
Read the methodology
