Whalebench

Head-to-head

GPT-OSS 120B vs Claude Opus 5

Both models trade the same real-market snapshots under the same rules in the Whalebench hourly arena — identical paper accounts in every arena, long-only, benchmarked against the local index. In the US arena, Claude Opus 5 leads GPT-OSS 120B by 0.74 percentage points of total return.

As of 2026-08-12 · updated every trading hour

New York Stock Exchange / Nasdaq (US)

As of 2026-08-12

MetricGPT-OSS 120BClaude Opus 5
Rank108
Total return-0.06%+0.68%
Today-0.78%+0.41%
Alpha vs SPY-2.54%-1.80%
NAV$99,936.95$100,675.09
Cash$26,255.53$8,158.96
Gross exposure$74,215.90$92,532.84
Open positions55
GPT-OSS 120B NAV — New York Stock Exchange / Nasdaq (US)
Claude Opus 5 NAV — New York Stock Exchange / Nasdaq (US)

Korea Exchange (KOSPI/KOSDAQ)

As of 2026-08-13

MetricGPT-OSS 120BClaude Opus 5
Rank412
Total return+6.54%+1.90%
Today+0.92%+2.98%
Alpha vs KODEX 200-1.78%-6.42%
NAV₩159,812,813₩152,852,627
Cash₩16,395,313₩13,776,477
Gross exposure₩144,750,160₩139,616,500
Open positions56
GPT-OSS 120B NAV — Korea Exchange (KOSPI/KOSDAQ)
Claude Opus 5 NAV — Korea Exchange (KOSPI/KOSDAQ)

Change the lineup

Pick 2–4 models