SPY vs STEM: Correlation
How closely do SPDR S&P 500 ETF Trust (SPY) and Stem, Inc. (STEM) trade together? Their weekly returns over three years give a correlation of 0.28, which is weak.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are SPY and STEM?
Over the past 3 years, SPY and STEM moved with a correlation of 0.28, which is weak. The past 12 months show a tighter link (0.49) than the 3-year average (0.28). Over 5 years the correlation is 0.35, and the annualized covariance of weekly returns is 520.6 %².
Among the 4755 assets we track against SPY, STEM ranks #2479 by 3-year correlation. Correlation aside, the last 12 months split them widely, with SPY ahead by 85.5 points (+20.6% versus -64.9%). Risk is not evenly split, since STEM carries 9.0 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.
SPY vs STEM: side by side
| SPY (SPDR S&P 500 ETF Trust) | STEM (Stem, Inc.) | |
|---|---|---|
| 1-year return | +20.6% | -64.9% |
| 5-year return | +82.4% | -98.9% |
| Volatility (ann.) | 14.5% | 129.9% |
| Beta vs S&P 500 | 1.00 | 2.49 |
| Max drawdown (3Y) | -18.8% | -95.5% |
| Market cap | – | $0.1B |
| P/E (trailing) | – | – |
| Dividend yield | 1.01% | 0.00% |
| Expense ratio | 0.09% | – |
| Assets under management | $795.3B | – |
| Sector / category | ETF · US Large Cap | US Listed |
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 | SPY | STEM |
|---|---|---|
| 2022 | -18.2% | -52.9% |
| 2023 | +26.2% | -56.6% |
| 2024 | +24.9% | -84.5% |
| 2025 | +17.7% | +24.8% |
| 2026 | +13.7% | -62.1% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are SPY and STEM good diversifiers for each other?
Yes, to a useful degree: a correlation of 0.28 leaves real independence between the two, which historically damped combined volatility.
FAQ
What is the correlation between SPY and STEM?
Using weekly returns as of 2026-08-27: 0.28 over 3 years, with 0.49 over the last year and 0.35 over 5 years.
Is STEM a good diversifier for SPY?
Yes, to a useful degree: a correlation of 0.28 leaves real independence between the two, which historically damped combined volatility.
What does a correlation of 0.28 mean?
A reading of 0.28 sits on a scale from −1 (opposite moves) through 0 (unrelated) to +1 (identical moves). Correlation captures direction, not magnitude or performance.
Use this data
$ curl https://www.pairbook.io/api/v1/pairs/spy-vs-stem.json
Embed this badge (it refreshes with the data), with attribution:
[](https://www.pairbook.io/pair/spy-vs-stem/)
No key needed, free to use. Full endpoint list in the API documentation.
Related comparisons
Hubs: SPY correlations · STEM correlations
