POST vs SPY: Correlation
How closely do Post Holdings, Inc. (POST) and SPDR S&P 500 ETF Trust (SPY) trade together? Their weekly returns over three years give a correlation of 0.07, which is near-zero.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are POST and SPY?
On 3 years of weekly data the POST/SPY correlation comes out at 0.07, near zero, meaning they move largely independently. The relationship has been stable: the 1-year correlation (-0.02) sits close to the 3-year figure. The 5-year figure is 0.19, and annualized covariance runs at 23.1 %².
Among the 19 assets we track against POST, SPY ranks #9 by 3-year correlation. The last year tells two different stories: SPY led by 48.7 percentage points, -28.1% for POST against +20.6% for SPY. One caveat on sizing: POST is 1.6 times as volatile as the other leg, so an equal-dollar split is far from equal-risk.
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.
POST vs SPY: side by side
| POST (Post Holdings, Inc.) | SPY (SPDR S&P 500 ETF Trust) | |
|---|---|---|
| 1-year return | -28.1% | +20.6% |
| 5-year return | +11.2% | +82.4% |
| Volatility (ann.) | 23.0% | 14.5% |
| Beta vs S&P 500 | 0.11 | 1.00 |
| Max drawdown (3Y) | -36.9% | -18.8% |
| Market cap | $3.7B | – |
| P/E (trailing) | 14.9 | – |
| 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 | POST | SPY |
|---|---|---|
| 2022 | +22.3% | -18.2% |
| 2023 | -2.4% | +26.2% |
| 2024 | +30.0% | +24.9% |
| 2025 | -13.5% | +17.7% |
| 2026 | -17.7% | +13.7% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are POST and SPY good diversifiers for each other?
Yes. With a correlation of 0.07, POST and SPY have moved largely independently, which makes them a genuinely diversifying pair by historical standards.
FAQ
What is the correlation between POST and SPY?
As of 2026-08-27, the correlation of weekly returns between POST and SPY is 0.07 over 3 years, -0.02 over 1 year and 0.19 over 5 years.
Is SPY a good diversifier for POST?
Yes. With a correlation of 0.07, POST and SPY have moved largely independently, which makes them a genuinely diversifying pair by historical standards.
What does a correlation of 0.07 mean?
On the −1 to +1 scale, 0.07 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.
Use this data
$ curl https://www.pairbook.io/api/v1/pairs/post-vs-spy.json
Embed this badge (it refreshes with the data), with attribution:
[](https://www.pairbook.io/pair/post-vs-spy/)
Free with attribution; caching and terms are described in the API documentation.
Related comparisons
Hubs: POST correlations · SPY correlations
