Summary
- Global stock markets have become more concentrated—but not in every way.
- Debt concentration has also declined, with the low or zero interest rates that followed the global financial crisis allowing companies to borrow more cheaply.
- Trading activity has become heavily concentrated, with investors increasingly directing flows toward the largest and most visible companies.
Ashi Sae Yang/iStock via Getty Images
Global stock markets have become more concentrated—but not in every way.
In recent years, a few high-profile technology companies have dominated the returns of both US and global stock indices.
Mega-cap companies in
