S&P 500 vs Nasdaq 100
US stocks (S&P 500) · the Nasdaq 100 — correlation 0.93
1-year rolling correlation · green together, red apartas of 2026-09-11
- +0.93normally
- +0.86in crashes
- +0.73 ~ +0.981-year range
- 1.04positions if held 50/50
Holding both is holding one
They correlate 0.93. Held half and half, that is 1.04 positions by risk — the split is in your head, not in the portfolio.
Choosing between US stocks (S&P 500) and the Nasdaq 100 may be a matter of taste. Owning both is not diversification.
Try it on your own portfolio
Opens with these two already entered. Add what you hold and the vs the rest and New columns answer whether to add one more.
Open with US stocks (S&P 500) · the Nasdaq 100Weekly returns, 611 weeks since 2015, every price converted to USD. “Crashes” means the 5% of weeks US stocks (S&P 500) fell hardest. One sample, one window — not a promise about the future.