JPMorgan's AI agents beat 60/40 portfolios in backtests—but key details are missing

Eight AI agents outperformed a traditional 60/40 portfolio in JPMorgan's historical backtests (July 2026). The bank hasn't disclosed out-of-sample testing, transaction costs, turnover, or risk-adjusted returns (Sharpe ratio). Without these, results may reflect curve-fitting—beating past benchmarks is easier than predicting future returns. For institutional investors, the distinction is crucial.