PNBK vs SPRO: Correlation
Patriot National Bancorp Inc. (PNBK) and Spero Therapeutics, Inc. (SPRO) show a negative relationship: their 3-year correlation of weekly returns is -0.29.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are PNBK and SPRO?
Across a 3-year window, the weekly returns of PNBK and SPRO correlate at -0.29, negative, meaning they tend to move in opposite directions. Lately the two have moved closer together, with the 1-year correlation at -0.00 versus -0.29 over 3 years. Stretching to 5 years gives -0.24, with an annualized covariance of -5139.6 %².
Among the 15 assets we track against PNBK, SPRO sits near the bottom by co-movement, at rank #13. On 12-month performance PNBK holds a 6.8-point edge, -32.1% against -38.9%.
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.
PNBK vs SPRO: side by side
| PNBK (Patriot National Bancorp Inc.) | SPRO (Spero Therapeutics, Inc.) | |
|---|---|---|
| 1-year return | -32.1% | -38.9% |
| 5-year return | -89.0% | -93.3% |
| Volatility (ann.) | 112.5% | 159.8% |
| Beta vs S&P 500 | 0.76 | 1.61 |
| Max drawdown (3Y) | -89.4% | -68.9% |
| Market cap | $0.1B | $0.1B |
| P/E (trailing) | – | 8.6 |
| Dividend yield | 0.00% | 0.00% |
| Sector / category | US Listed | US Listed |
Year-by-year returns
| Year | PNBK | SPRO |
|---|---|---|
| 2022 | -31.8% | -89.2% |
| 2023 | -63.9% | -15.0% |
| 2024 | -49.3% | -29.9% |
| 2025 | -6.2% | +126.2% |
| 2026 | -43.7% | -48.1% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are PNBK and SPRO good diversifiers for each other?
Yes: at -0.29, the two have gone their own ways historically, which is what genuine diversification looks like.
FAQ
What is the correlation between PNBK and SPRO?
As of 2026-08-27, the correlation of weekly returns between PNBK and SPRO is -0.29 over 3 years, -0.00 over 1 year and -0.24 over 5 years.
Is SPRO a good diversifier for PNBK?
Yes: at -0.29, the two have gone their own ways historically, which is what genuine diversification looks like.
What does a correlation of -0.29 mean?
A reading of -0.29 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/pnbk-vs-spro.json
Drop this badge in a README or notebook; it updates with the data:
[](https://www.pairbook.io/pair/pnbk-vs-spro/)
Free with attribution; caching and terms are described in the API documentation.
Related comparisons
Hubs: PNBK correlations · SPRO correlations
