NAII vs SPY: Correlation
How closely do Natural Alternatives International, Inc. (NAII) and SPDR S&P 500 ETF Trust (SPY) trade together? Their weekly returns over three years give a correlation of 0.03, which is near-zero.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are NAII and SPY?
On 3 years of weekly data the NAII/SPY correlation comes out at 0.03, near zero, meaning they move largely independently. Recent behaviour matches the longer record: 0.07 over 1 year against 0.03 over 3. The 5-year figure is 0.09, and annualized covariance runs at 19.2 %².
By 3-year correlation, SPY places #6 of the 14 assets tracked against NAII. The last year tells two different stories: SPY led by 56.6 percentage points, -36.0% for NAII against +20.6% for SPY. Risk is not evenly split, since NAII carries 3.4 times the volatility of the other side.
How is this computed?
Pearson correlation on weekly returns: ρ(A,B) = cov(rA, rB) / (σA · σB), over windows of 52, 156 and 260 weeks. Covariance is annualized (×52) and expressed in %². Full definitions on the methodology page.
NAII vs SPY: side by side
| NAII (Natural Alternatives International, Inc.) | SPY (SPDR S&P 500 ETF Trust) | |
|---|---|---|
| 1-year return | -36.0% | +20.6% |
| 5-year return | -85.1% | +82.4% |
| Volatility (ann.) | 49.2% | 14.5% |
| Beta vs S&P 500 | 0.09 | 1.00 |
| Max drawdown (3Y) | -71.7% | -18.8% |
| Market cap | – | – |
| P/E (trailing) | – | – |
| Dividend yield | 0.00% | 1.01% |
| Expense ratio | – | 0.09% |
| Assets under management | – | $795.3B |
| Sector / category | US Listed | ETF · US Large Cap |
SPY is a Large Blend fund from State Street Investment Management: $795.3B under management, 504 holdings, a 0.09% expense ratio, a 1.01% trailing dividend yield.
Year-by-year returns
| Year | NAII | SPY |
|---|---|---|
| 2022 | -33.7% | -18.2% |
| 2023 | -22.2% | +26.2% |
| 2024 | -34.0% | +24.9% |
| 2025 | -16.9% | +17.7% |
| 2026 | -36.0% | +13.7% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are NAII and SPY good diversifiers for each other?
By historical standards, yes. A correlation of 0.03 means the two rarely move for the same reasons.
FAQ
What is the correlation between NAII and SPY?
Using weekly returns as of 2026-08-27: 0.03 over 3 years, with 0.07 over the last year and 0.09 over 5 years.
Is SPY a good diversifier for NAII?
By historical standards, yes. A correlation of 0.03 means the two rarely move for the same reasons.
What does a correlation of 0.03 mean?
On the −1 to +1 scale, 0.03 describes how much the two returns move together: +1 is lockstep, 0 is independence, negative values mean opposite directions. It says nothing about which performed better.
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Related comparisons
Hubs: NAII correlations · SPY correlations
