The managers running the biggest active funds picked stocks that beat the market in 2025 — and most still lagged their benchmark. A Morningstar do-nothing experiment and a body of academic research explain why active funds underperform even when the picking is good: skilled buying undone by poor selling, the hidden cost of trading, and the incentives that keep managers churning. The UK evidence points the same way.
Active share was meant to identify fund managers worth paying for. A new study covering four decades of US fund data finds that high active share funds now systematically underperform low active share funds. The reversal began in 2010 and coincides with the rise of passive investing creating structural pressure on active managers.
