SPRO vs TLYS: Correlation
Measured on weekly returns over the past three years, Spero Therapeutics, Inc. (SPRO) and Tilly's, Inc. (TLYS) carry a correlation of 0.40, a moderate link.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are SPRO and TLYS?
On 3 years of weekly data the SPRO/TLYS correlation comes out at 0.40, moderate. Lately the two have drifted apart, with the 1-year correlation at 0.14 versus 0.40 over 3 years. The 5-year figure is 0.34, and annualized covariance runs at 6168.0 %².
Within SPRO's tracked universe of 18 assets, TLYS comes in at #7 by 3-year correlation. The last year tells two different stories: TLYS led by 144.2 percentage points, -38.9% for SPRO against +105.3% for TLYS. Risk is not evenly split, since SPRO carries 1.7 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.
SPRO vs TLYS: side by side
| SPRO (Spero Therapeutics, Inc.) | TLYS (Tilly's, Inc.) | |
|---|---|---|
| 1-year return | -38.9% | +105.3% |
| 5-year return | -93.3% | -74.2% |
| Volatility (ann.) | 159.8% | 96.5% |
| Beta vs S&P 500 | 1.61 | 0.68 |
| Max drawdown (3Y) | -68.9% | -92.3% |
| 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 | SPRO | TLYS |
|---|---|---|
| 2022 | -89.2% | -43.8% |
| 2023 | -15.0% | -16.7% |
| 2024 | -29.9% | -43.6% |
| 2025 | +126.2% | -53.2% |
| 2026 | -48.1% | +93.0% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are SPRO and TLYS good diversifiers for each other?
Reasonably. At 0.40, SPRO and TLYS keep a meaningful degree of independence, and combining them has historically reduced portfolio volatility.
FAQ
What is the correlation between SPRO and TLYS?
The SPRO/TLYS correlation stands at 0.40 on a 3-year window (1 year: 0.14, 5 years: 0.34), computed from weekly returns as of 2026-08-27.
Is TLYS a good diversifier for SPRO?
Reasonably. At 0.40, SPRO and TLYS keep a meaningful degree of independence, and combining them has historically reduced portfolio volatility.
What does a correlation of 0.40 mean?
Correlation ranges from −1 to +1. Values near +1 mean two assets move together, near 0 that they move independently, and negative values that they tend to move in opposite directions. It measures co-movement, not performance.
Use this data
$ curl https://www.pairbook.io/api/v1/pairs/spro-vs-tlys.json
Drop this badge in a README or notebook; it updates with the data:
[](https://www.pairbook.io/pair/spro-vs-tlys/)
Free with attribution; caching and terms are described in the API documentation.
Related comparisons
Hubs: SPRO correlations · TLYS correlations
