SPY vs TTEK: Correlation
SPDR S&P 500 ETF Trust (SPY) and Tetra Tech, Inc. (TTEK) show a weak relationship: their 3-year correlation of weekly returns is 0.26.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are SPY and TTEK?
On 3 years of weekly data the SPY/TTEK correlation comes out at 0.26, weak. Little has changed lately, as the 1-year reading of 0.27 lands near the 3-year figure. The 5-year figure is 0.46, and annualized covariance runs at 112.0 %².
By 3-year correlation, TTEK places #2676 of the 4755 assets tracked against SPY. Correlation aside, the last 12 months split them widely, with SPY ahead by 20.7 points (+20.6% versus -0.1%). One caveat on sizing: TTEK is 2.1 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.
SPY vs TTEK: side by side
| SPY (SPDR S&P 500 ETF Trust) | TTEK (Tetra Tech, Inc.) | |
|---|---|---|
| 1-year return | +20.6% | -0.1% |
| 5-year return | +82.4% | +32.3% |
| Volatility (ann.) | 14.5% | 30.3% |
| Beta vs S&P 500 | 1.00 | 0.54 |
| Max drawdown (3Y) | -18.8% | -47.5% |
| Market cap | – | $9.4B |
| P/E (trailing) | – | 22.1 |
| Dividend yield | 1.01% | 0.73% |
| Expense ratio | 0.09% | – |
| Assets under management | $795.3B | – |
| Sector / category | ETF · US Large Cap | US Listed |
SPY, State Street Investment Management's Large Blend fund, carries $795.3B under management, 504 holdings, a 0.09% expense ratio, a 1.01% trailing dividend yield.
Year-by-year returns
| Year | SPY | TTEK |
|---|---|---|
| 2022 | -18.2% | -14.0% |
| 2023 | +26.2% | +15.7% |
| 2024 | +24.9% | +20.0% |
| 2025 | +17.7% | -15.2% |
| 2026 | +13.7% | +9.9% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are SPY and TTEK good diversifiers for each other?
A fair diversifier. At 0.26, enough of each asset's movement is its own that the pair has smoothed outcomes historically.
FAQ
What is the correlation between SPY and TTEK?
As of 2026-08-27, the correlation of weekly returns between SPY and TTEK is 0.26 over 3 years, 0.27 over 1 year and 0.46 over 5 years.
Is TTEK a good diversifier for SPY?
A fair diversifier. At 0.26, enough of each asset's movement is its own that the pair has smoothed outcomes historically.
What does a correlation of 0.26 mean?
On the −1 to +1 scale, 0.26 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/spy-vs-ttek.json
Drop this badge in a README or notebook; it updates with the data:
[](https://www.pairbook.io/pair/spy-vs-ttek/)
The core API is free. Terms and every endpoint in the API documentation.
Related comparisons
Hubs: SPY correlations · TTEK correlations
