BCDA vs SPY: Correlation
Measured on weekly returns over the past three years, BioCardia, Inc. (BCDA) and SPDR S&P 500 ETF Trust (SPY) carry a correlation of 0.23, a weak link.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are BCDA and SPY?
Across a 3-year window, the weekly returns of BCDA and SPY correlate at 0.23, weak. Lately the two have drifted apart, with the 1-year correlation at -0.04 versus 0.23 over 3 years. Stretching to 5 years gives 0.18, with an annualized covariance of 338.1 %².
Among the 13 assets we track against BCDA, SPY ranks #8 by 3-year correlation. The last year tells two different stories: SPY led by 60.3 percentage points, -39.7% for BCDA against +20.6% for SPY. One caveat on sizing: BCDA is 7.0 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.
BCDA vs SPY: side by side
| BCDA (BioCardia, Inc.) | SPY (SPDR S&P 500 ETF Trust) | |
|---|---|---|
| 1-year return | -39.7% | +20.6% |
| 5-year return | -97.4% | +82.4% |
| Volatility (ann.) | 102.2% | 14.5% |
| Beta vs S&P 500 | 1.62 | 1.00 |
| Max drawdown (3Y) | -95.2% | -18.8% |
| Market cap | – | – |
| P/E (trailing) | – | – |
| Dividend yield | 0.00% | 1.01% |
| Expense ratio | – | 0.09% |
| Assets under management | – | $795.3B |
| Sector / category | US Listed | ETF · US Large Cap |
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 | BCDA | SPY |
|---|---|---|
| 2022 | +7.7% | -18.2% |
| 2023 | -68.4% | +26.2% |
| 2024 | -78.0% | +24.9% |
| 2025 | -42.7% | +17.7% |
| 2026 | -6.4% | +13.7% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are BCDA and SPY good diversifiers for each other?
Reasonably. At 0.23, BCDA and SPY keep a meaningful degree of independence, and combining them has historically reduced portfolio volatility.
FAQ
What is the correlation between BCDA and SPY?
Using weekly returns as of 2026-08-27: 0.23 over 3 years, with -0.04 over the last year and 0.18 over 5 years.
Is SPY a good diversifier for BCDA?
Reasonably. At 0.23, BCDA and SPY keep a meaningful degree of independence, and combining them has historically reduced portfolio volatility.
What does a correlation of 0.23 mean?
A reading of 0.23 sits on a scale from −1 (opposite moves) through 0 (unrelated) to +1 (identical moves). Correlation captures direction, not magnitude or performance.
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Related comparisons
Hubs: BCDA correlations · SPY correlations
