CTOS vs PRTS: Correlation
How closely do Custom Truck One Source, Inc. (CTOS) and CarParts.com, Inc. (PRTS) trade together? Their weekly returns over three years give a correlation of 0.33, which is moderate.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are CTOS and PRTS?
On 3 years of weekly data the CTOS/PRTS correlation comes out at 0.33, moderate. Recent behaviour matches the longer record: 0.23 over 1 year against 0.33 over 3. The 5-year figure is 0.31, and annualized covariance runs at 1315.0 %².
PRTS is close to the least connected end of CTOS's tracked universe, ranking #9 of 13. Correlation aside, the last 12 months split them widely, with CTOS ahead by 70.5 points (+61.3% versus -9.2%).
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.
CTOS vs PRTS: side by side
| CTOS (Custom Truck One Source, Inc.) | PRTS (CarParts.com, Inc.) | |
|---|---|---|
| 1-year return | +61.3% | -9.2% |
| 5-year return | +8.1% | -95.9% |
| Volatility (ann.) | 54.4% | 72.4% |
| Beta vs S&P 500 | 1.42 | 0.44 |
| Max drawdown (3Y) | -55.6% | -92.1% |
| Market cap | $2.2B | $0.1B |
| P/E (trailing) | 107.3 | – |
| Dividend yield | 0.00% | 0.00% |
| Sector / category | US Listed | US Listed |
Year-by-year returns
| Year | CTOS | PRTS |
|---|---|---|
| 2022 | -21.0% | -44.1% |
| 2023 | -2.2% | -49.5% |
| 2024 | -22.2% | -65.8% |
| 2025 | +19.8% | -53.7% |
| 2026 | +67.7% | +43.4% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are CTOS and PRTS good diversifiers for each other?
A fair diversifier. At 0.33, enough of each asset's movement is its own that the pair has smoothed outcomes historically.
FAQ
What is the correlation between CTOS and PRTS?
Using weekly returns as of 2026-08-27: 0.33 over 3 years, with 0.23 over the last year and 0.31 over 5 years.
Is PRTS a good diversifier for CTOS?
A fair diversifier. At 0.33, enough of each asset's movement is its own that the pair has smoothed outcomes historically.
What does a correlation of 0.33 mean?
On the −1 to +1 scale, 0.33 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/ctos-vs-prts.json
Drop this badge in a README or notebook; it updates with the data:
[](https://www.pairbook.io/pair/ctos-vs-prts/)
No key needed, free to use. Full endpoint list in the API documentation.
Related comparisons
Hubs: CTOS correlations · PRTS correlations
