Insights & Perspectives from Commons Capital
June 26, 2026
The Hidden Concentration in "Diversified" Portfolios: What This Week Showed About Owning the S&P 500
On Tuesday afternoon, three stocks moved enough to pull the entire S&P 500 down 1.4 percent in a single session. Most investors holding "the market" through a passive index fund or ETF watched their balance dip and concluded, reasonably, that the market had a bad day.






