Poor Charlie's Almanack: The Essential Wit and Wisdom of Charles T. Munger · chapter 3 · id poor-charlies-almanack-c3-07-munger-advocates-sit-on-your-a

“Munger advocates 'sit on your ass' investing -- making very few decisions with high conviction -- and claims this approach produces better returns than frequent trading.”

holdsconfidence: high✓ ZHP-verified + red-teamed

Receipts

Barber & Odean, 'Trading Is Hazardous to Your Wealth,' Journal of Finance (2000)DOI registry: valid

Individual investors who trade most actively earn an annual return of 11.4%, while the market return is 17.9%.

Kacperczyk et al., 'On the Industry Concentration of Actively Managed Equity Mutual Funds,' JoF (2005)DOI registry: valid

Concentrated mutual funds outperform diversified funds by 1.5% annually, on a risk-adjusted basis.

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