An experimental AI stock portfolio managed by Grok has outperformed the S&P 500, turning a $100,000 starting investment into $148,485 in less than nine months.
In this line, data from the *Rallies Arena *competition show that the portfolio has generated a total return of 48.48% since late November 2025. Over the same period, an equivalent investment tracking the S&P 500 would have grown to about $114,101, representing a return of 14.10%.
The result means Grok beat the benchmark index by 34.38 percentage points. The performance shows the portfolio tracking closely with the S&P 500 during the first few months of the challenge before pulling sharply ahead in April and May.
The largest gains came during a strong rally that pushed the portfolio above $150,000 in late May. Although the account later experienced some volatility, it retained most of its gains and continued trending higher into August.
The portfolio recorded a Sharpe ratio of 2.19, indicating strong risk-adjusted returns. Meanwhile, the maximum drawdown stood at 13.5%, suggesting losses remained relatively contained despite the aggressive performance.
Micron leads rally #
The portfolio is heavily concentrated in three stocks, with Micron Technology (NASDAQ: MU) accounting for the majority of assets.
Current holdings show approximately $95,800 invested in Micron, representing nearly two-thirds of the portfolio’s value. The remaining positions are concentrated in Salesforce (NYSE: CRM), valued at about $26,900, and ServiceNow (NYSE: NOW), worth roughly $24,200.
Micron’s strong rally during the artificial intelligence infrastructure boom has been the primary driver of returns. Demand for high-bandwidth memory chips used in AI systems has fueled investor interest in the semiconductor company, helping propel the portfolio well ahead of the broader market.
Notably, Rallies Arena operates a live competition in which multiple artificial intelligence models receive the same starting capital and access to market data. Each model independently selects stocks and manages its portfolio in an attempt to outperform both competing AI systems and the S&P 500.
As of August 2026, Grok remains one of the strongest performers in the contest. While the portfolio’s heavy exposure to Micron has amplified gains during the AI-led market rally, it also leaves performance highly dependent on the continued strength of a small number of positions.