BDBKX vs. FSOPX
BDBKX (iShares Russell 2000 Small-Cap Index Fund Class K) and FSOPX (Fidelity Series Small Cap Opportunities Fund) are both Small Cap Blend Equities funds. Over the past 10 years, BDBKX returned 11.18%/yr vs 12.77%/yr for FSOPX. With a 0.97 correlation, they move nearly in lockstep. BDBKX charges 0.07%/yr vs 0.00%/yr for FSOPX.
Performance
BDBKX vs. FSOPX - Performance Comparison
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Returns By Period
In the year-to-date period, BDBKX achieves a 18.66% return, which is significantly higher than FSOPX's 16.83% return. Over the past 10 years, BDBKX has underperformed FSOPX with an annualized return of 11.18%, while FSOPX has yielded a comparatively higher 12.77% annualized return.
BDBKX
- 1D
- 0.92%
- 1M
- 4.99%
- YTD
- 18.66%
- 6M
- 17.35%
- 1Y
- 41.13%
- 3Y*
- 18.59%
- 5Y*
- 6.60%
- 10Y*
- 11.18%
FSOPX
- 1D
- 0.85%
- 1M
- 1.12%
- YTD
- 16.83%
- 6M
- 15.66%
- 1Y
- 40.89%
- 3Y*
- 21.01%
- 5Y*
- 11.01%
- 10Y*
- 12.77%
BDBKX vs. FSOPX - Yearly Performance Comparison
| 2026 (YTD) | 2025 | 2024 | 2023 | 2022 | 2021 | 2020 | 2019 | 2018 | 2017 | |
|---|---|---|---|---|---|---|---|---|---|---|
BDBKX iShares Russell 2000 Small-Cap Index Fund Class K | 18.66% | 12.81% | 11.40% | 17.04% | -20.32% | 14.59% | 20.02% | 25.66% | -11.01% | 14.71% |
FSOPX Fidelity Series Small Cap Opportunities Fund | 16.83% | 15.81% | 15.31% | 20.38% | -17.82% | 23.39% | 17.03% | 29.92% | -8.12% | 11.10% |
Correlation
The correlation between BDBKX and FSOPX is 0.94, indicating a strong positive relationship between their price movements. Combining them offers limited diversification - they tend to fall together during downturns.
| Correlation | |
|---|---|
Correlation (1Y) Calculated over the trailing 1-year period | 0.94 |
Correlation (3Y) Calculated over the trailing 3-year period | 0.97 |
Correlation (5Y) Calculated over the trailing 5-year period | 0.97 |
Correlation (10Y) Calculated over the trailing 10-year period | 0.97 |
Correlation (All Time) Calculated using the full available price history since Apr 1, 2011 | 0.97 |
The correlation between BDBKX and FSOPX has been stable across timeframes, ranging from 0.94 to 0.97 - a consistent structural relationship.
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Return for Risk
BDBKX vs. FSOPX — Risk / Return Rank
BDBKX
FSOPX
BDBKX vs. FSOPX - Risk-Adjusted Trends Comparison
This table presents a comparison of risk-adjusted performance metrics for iShares Russell 2000 Small-Cap Index Fund Class K (BDBKX) and Fidelity Series Small Cap Opportunities Fund (FSOPX). Risk-adjusted metrics are performance indicators that assess an investment's returns in relation to its risk, enabling a more accurate comparison of different investment options.
| BDBKX | FSOPX | Difference | |
|---|---|---|---|
| Sharpe ratioReturn per unit of total volatility | -0.14 | ||
| Sortino ratioReturn per unit of downside risk | -0.28 | ||
| Omega ratioGain probability vs. loss probability | 1.37 | 1.41 | -0.04 |
| Calmar ratioReturn relative to maximum drawdown | 3.97 | 4.35 | -0.38 |
| Martin ratioReturn relative to average drawdown | 14.10 | 17.03 | -2.93 |
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month. | |||
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Sharpe Ratios by Period
| BDBKX | FSOPX | Difference | |
|---|---|---|---|
Sharpe Ratio (1Y)Calculated over the trailing 1-year period | 2.28 | 2.42 | -0.14 |
Sharpe Ratio (5Y)Calculated over the trailing 5-year period | 0.29 | 0.51 | -0.22 |
Sharpe Ratio (10Y)Calculated over the trailing 10-year period | 0.47 | 0.58 | -0.11 |
Sharpe Ratio (All Time)Calculated using the full available price history | 0.44 | 0.39 | +0.05 |
Drawdowns
BDBKX vs. FSOPX - Drawdown Comparison
The maximum BDBKX drawdown since its inception was -41.66%, smaller than the maximum FSOPX drawdown of -61.75%. Use the drawdown chart below to compare losses from any high point for BDBKX and FSOPX.
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Drawdown Indicators
| BDBKX | FSOPX | Difference | |
|---|---|---|---|
Max DrawdownLargest peak-to-trough decline | -41.66% | -61.75% | +20.09% |
Max Drawdown (1Y)Largest decline over 1 year | -10.97% | -9.99% | -0.98% |
Max Drawdown (3Y)Largest decline over 3 years | -27.53% | -27.17% | -0.36% |
Max Drawdown (5Y)Largest decline over 5 years | -31.96% | -30.06% | -1.90% |
Max Drawdown (10Y)Largest decline over 10 years | -41.66% | -39.15% | -2.51% |
Current DrawdownCurrent decline from peak | -0.13% | -1.66% | +1.53% |
Average DrawdownAverage peak-to-trough decline | -8.74% | -10.37% | +1.63% |
Ulcer IndexDepth and duration of drawdowns from previous peaks | 3.08% | 2.54% | +0.54% |
Volatility
BDBKX vs. FSOPX - Volatility Comparison
iShares Russell 2000 Small-Cap Index Fund Class K (BDBKX) has a higher volatility of 5.56% compared to Fidelity Series Small Cap Opportunities Fund (FSOPX) at 5.26%. This indicates that BDBKX's price experiences larger fluctuations and is considered to be riskier than FSOPX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.
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Volatility by Period
| BDBKX | FSOPX | Difference | |
|---|---|---|---|
Volatility (1M)Calculated over the trailing 1-month period | 5.56% | 5.26% | +0.30% |
Volatility (6M)Calculated over the trailing 6-month period | 13.55% | 13.46% | +0.09% |
Volatility (1Y)Calculated over the trailing 1-year period | 19.09% | 17.92% | +1.17% |
Volatility (5Y)Calculated over the trailing 5-year period, annualized | 23.17% | 21.70% | +1.47% |
Volatility (10Y)Calculated over the trailing 10-year period, annualized | 23.71% | 21.99% | +1.72% |
BDBKX vs. FSOPX - Expense Ratio Comparison
BDBKX has a 0.07% expense ratio, which is higher than FSOPX's 0.00% expense ratio. However, both funds are considered low-cost compared to the broader market, where average expense ratios usually range from 0.3% to 0.9%.
Dividends
BDBKX vs. FSOPX - Dividend Comparison
BDBKX's dividend yield for the trailing twelve months is around 2.67%, less than FSOPX's 3.78% yield.
| Position | TTM | 2025 | 2024 | 2023 | 2022 | 2021 | 2020 | 2019 | 2018 | 2017 | 2016 | 2015 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
BDBKX iShares Russell 2000 Small-Cap Index Fund Class K | 2.67% | 3.17% | 4.84% | 2.96% | 1.76% | 7.67% | 1.45% | 3.47% | 4.29% | 3.18% | 4.62% | 3.64% |
FSOPX Fidelity Series Small Cap Opportunities Fund | 3.78% | 4.41% | 9.41% | 0.98% | 5.16% | 30.85% | 2.01% | 6.67% | 13.99% | 10.31% | 0.69% | 5.93% |
Frequently Asked Questions
With a correlation of 0.94, BDBKX and FSOPX move almost identically. Holding both adds very little diversification - you're essentially doubling your position in the same market segment. Choosing one is usually more capital-efficient.
BDBKX has higher volatility (5.56%) compared to FSOPX (5.26%). In terms of maximum drawdown, BDBKX dropped -41.66% vs FSOPX's -61.75%.
FSOPX currently has the higher Sharpe Ratio (2.42 vs 2.28), meaning it's delivered slightly more return per unit of risk over the trailing 12 months. However, this ranking shifts over time - use the Risk/Return Score above for a more comprehensive view that combines Sharpe, Sortino, and other measures used by quantitative funds.
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