BST vs XLK: Correlation
How closely do BlackRock Science and Technology Trust (BST) and Technology Select Sector SPDR Fund (XLK) trade together? Their weekly returns over three years give a correlation of 0.85, which is very strong.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are BST and XLK?
On 3 years of weekly data the BST/XLK correlation comes out at 0.85, very strong, meaning they move nearly in lockstep. Recent behaviour matches the longer record: 0.83 over 1 year against 0.85 over 3. The 5-year figure is 0.86, and annualized covariance runs at 452.9 %².
Among the 25 assets we track against BST, XLK ranks #5 by 3-year correlation. Their 12-month results are close: +40.7% for BST against +43.4% for XLK.
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.
BST vs XLK: side by side
| BST (BlackRock Science and Technology Trust) | XLK (Technology Select Sector SPDR Fund) | |
|---|---|---|
| 1-year return | +40.7% | +43.4% |
| 5-year return | +46.7% | +145.2% |
| Volatility (ann.) | 22.2% | 24.0% |
| Beta vs S&P 500 | 1.27 | 1.50 |
| Max drawdown (3Y) | -23.4% | -25.7% |
| Market cap | – | – |
| P/E (trailing) | 6.9 | – |
| Dividend yield | 0.00% | 0.45% |
| Expense ratio | – | 0.08% |
| Assets under management | – | $115.4B |
| Sector / category | US Listed | Sector ETF |
On the fund side, XLK sits in the Technology category at State Street Investment Management, with $115.4B under management, 73 holdings, a 0.08% expense ratio, a 0.45% trailing dividend yield.
Year-by-year returns
| Year | BST | XLK |
|---|---|---|
| 2022 | -38.3% | -27.7% |
| 2023 | +30.1% | +56.0% |
| 2024 | +18.0% | +21.6% |
| 2025 | +23.7% | +24.6% |
| 2026 | +30.9% | +31.3% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are BST and XLK good diversifiers for each other?
No: a correlation of 0.85 means BST and XLK tend to fall together, which is precisely when diversification is supposed to help.
FAQ
What is the correlation between BST and XLK?
The BST/XLK correlation stands at 0.85 on a 3-year window (1 year: 0.83, 5 years: 0.86), computed from weekly returns as of 2026-08-27.
Is XLK a good diversifier for BST?
No: a correlation of 0.85 means BST and XLK tend to fall together, which is precisely when diversification is supposed to help.
What does a correlation of 0.85 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/bst-vs-xlk.json
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Related comparisons
Hubs: BST correlations · XLK correlations
