The Black Swan: The Impact of the Highly Improbable · chapter 4 · id the-black-swan-c4-04-survivorship-bias-in-mutual-fu

“Survivorship bias in mutual funds is substantial: over 20-year periods, nearly 64% of domestic stock funds are shuttered or merged, meaning performance databases that only track surviving funds systematically overstate industry returns.”

holdsconfidence: high⚠ extracted by pipeline, re-audit pending

Receipts

S&P Dow Jones Indices: SPIVA U.S. Mid-Year 2025paywalled — manual check queued

Over the 20 years ending December 2024, nearly 64% of domestic stock funds were shuttered or folded into other portfolios. Across every category, the majority of active funds underperform their benchmark over 10, 15, and 20 years.

Bogleheads: Survivorship Biaspaywalled — manual check queued

Studies estimate survivorship bias in the U.S. mutual fund industry at approximately 0.9% per annum, measured as the difference between average risk-adjusted returns of surviving funds versus all funds.

ETF.com: Survivor Bias and Improper Measurementpaywalled — manual check queued

Survivorship bias inflates reported mutual fund returns by 0.5-1.5% annually depending on the time period and fund category, with small-cap and growth funds showing the largest bias.

This claim is a stable, citable object. If you can falsify a verdict, tell us — corrections are loud here.