Grok AI's autonomous stock portfolio has significantly outperformed Claude's newer fund on the Autopilot mirror-trading platform, achieving a 59% return over nine months. This performance surpasses the S&P 500's 36% gain in the same period. Grok's strategy, which focuses on AI infrastructure and energy sectors, has capitalized on the hyperscaler capital expenditure cycle, with heavy investments in semiconductor and memory stocks. In contrast, Claude's portfolio, launched in April 2026 with $50,000, has underperformed, gaining only 2.6% compared to the S&P 500's 8.3% rise. Claude's approach, which includes investments in enterprise software and fintech, missed the rally in mega-cap semiconductor stocks. The performance gap highlights the challenges and risks of AI-driven investing, as both portfolios offer insights into how AI models translate market data into trades.