BSPAX vs. BDBKX

Last updated Jul 19, 2026

BSPAX (iShares S&P 500 Index Fund Investor A Shares) and BDBKX (iShares Russell 2000 Small-Cap Index Fund Class K) are both mutual funds - BSPAX is a S&P 500 fund tracking the S&P 500 Index, while BDBKX is a Small Cap Blend Equities fund tracking the Russell 2000 Index. Both are passively managed. Over the past 10 years, BSPAX returned 14.55%/yr vs 10.91%/yr for BDBKX. Their correlation of 0.82 suggests significant overlap in exposure. BSPAX charges 0.35%/yr vs 0.07%/yr for BDBKX.

Performance

BSPAX vs. BDBKX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in iShares S&P 500 Index Fund Investor A Shares (BSPAX) and iShares Russell 2000 Small-Cap Index Fund Class K (BDBKX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, BSPAX achieves a 9.42% return, which is significantly lower than BDBKX's 20.49% return. Over the past 10 years, BSPAX has outperformed BDBKX with an annualized return of 14.55%, while BDBKX has yielded a comparatively lower 10.91% annualized return.

BSPAX

• 1D: -1.01%
• 1M: -0.53%
• 6M: 7.88%
• YTD: 9.42%
• 1Y: 19.39%
• 3Y*: 19.01%
• 5Y*: 12.71%
• 10Y*: 14.55%

BDBKX

• 1D: -0.06%
• 1M: -0.19%
• 6M: 11.66%
• YTD: 20.49%
• 1Y: 34.27%
• 3Y*: 16.63%
• 5Y*: 8.02%
• 10Y*: 10.91%

*Multi-year figures are annualized to reflect compound growth (CAGR)

BSPAX vs. BDBKX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
BSPAX iShares S&P 500 Index Fund Investor A Shares	9.42%	17.46%	24.54%	25.85%	-18.40%	28.22%	18.05%	31.02%	-5.05%	20.97%
BDBKX iShares Russell 2000 Small-Cap Index Fund Class K	20.49%	12.81%	11.40%	17.04%	-20.32%	14.59%	20.02%	25.66%	-11.01%	14.71%

Correlation

The correlation between BSPAX and BDBKX is 0.78, which is moderate. They share some common price drivers but move independently often enough to provide real diversification benefit when combined.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	0.78
Correlation (3Y) Calculated over the trailing 3-year period	0.77
Correlation (5Y) Calculated over the trailing 5-year period	0.81
Correlation (10Y) Calculated over the trailing 10-year period	0.81
Correlation (All Time) Calculated using the full available price history since Jan 2, 2014	0.82

The correlation between BSPAX and BDBKX has been stable across timeframes, ranging from 0.77 to 0.82 - a consistent structural relationship.

Return for Risk

BSPAX vs. BDBKX — Risk / Return Rank

Compare risk-adjusted metric ranks to identify better-performing investments over the past 12 months.

BSPAX

BSPAX Risk / Return Rank: 48
BSPAX Sharpe Ratio Rank: 46
BSPAX Sortino Ratio Rank: 43
BSPAX Omega Ratio Rank: 45
BSPAX Calmar Ratio Rank: 48
BSPAX Martin Ratio Rank: 61

BDBKX

BDBKX Risk / Return Rank: 68
BDBKX Sharpe Ratio Rank: 65
BDBKX Sortino Ratio Rank: 64
BDBKX Omega Ratio Rank: 52
BDBKX Calmar Ratio Rank: 84
BDBKX Martin Ratio Rank: 78

The rank (0–100) shows how this investment's returns compare to the risk taken. Higher = better. Based on the past 12 months of data, combining Sharpe, Sortino, and other metrics used by quantitative funds and institutional investors.

BSPAX vs. BDBKX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for iShares S&P 500 Index Fund Investor A Shares (BSPAX) and iShares Russell 2000 Small-Cap Index Fund Class K (BDBKX). 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.

Values are calculated on a 1-year rolling basis and updated daily. Risk-adjusted metrics are more stable over longer periods — use the period switch above to explore them.

	BSPAX	BDBKX	Difference
Sharpe ratio: Return per unit of total volatility	1.55	1.83	-0.28
Sortino ratio: Return per unit of downside risk	2.15	2.59	-0.44
Omega ratio: Gain probability vs. loss probability	1.28	1.31	-0.03
Calmar ratio: Return relative to maximum drawdown	2.18	3.21	-1.04
Martin ratio: Return relative to average drawdown	9.50	11.36	-1.86

BSPAX vs. BDBKX - Sharpe Ratio Comparison

The current BSPAX Sharpe Ratio is 1.55, which is comparable to the BDBKX Sharpe Ratio of 1.83. The chart below compares the historical Sharpe Ratios of BSPAX and BDBKX, calculated using daily returns over the previous 12 months. A higher Sharpe Ratio indicates better risk-adjusted performance relative to the risk-free rate.

Drawdowns

BSPAX vs. BDBKX - Drawdown Comparison

The maximum BSPAX drawdown since its inception was -33.76%, smaller than the maximum BDBKX drawdown of -41.66%. Use the drawdown chart below to compare losses from any high point for BSPAX and BDBKX.

Drawdown Indicators

	BSPAX	BDBKX	Difference
Max Drawdown Largest peak-to-trough decline	-33.76%	-41.66%	+7.90%
Max Drawdown (1Y) Largest decline over 1 year	-8.95%	-10.97%	+2.02%
Max Drawdown (3Y) Largest decline over 3 years	-18.77%	-27.53%	+8.76%
Max Drawdown (5Y) Largest decline over 5 years	-24.70%	-31.96%	+7.26%
Max Drawdown (10Y) Largest decline over 10 years	-33.76%	-41.66%	+7.90%
Current Drawdown Current decline from peak	-1.90%	-1.62%	-0.28%
Average Drawdown Average peak-to-trough decline	-3.97%	-8.68%	+4.71%
Ulcer Index Depth and duration of drawdowns from previous peaks	2.05%	3.10%	-1.05%

Volatility

BSPAX vs. BDBKX - Volatility Comparison

The current volatility for iShares S&P 500 Index Fund Investor A Shares (BSPAX) is 3.37%, while iShares Russell 2000 Small-Cap Index Fund Class K (BDBKX) has a volatility of 3.70%. This indicates that BSPAX experiences smaller price fluctuations and is considered to be less risky than BDBKX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	BSPAX	BDBKX	Difference
Volatility (1M) Calculated over the trailing 1-month period	3.37%	3.70%	-0.33%
Volatility (6M) Calculated over the trailing 6-month period	10.04%	14.16%	-4.12%
Volatility (1Y) Calculated over the trailing 1-year period	12.59%	19.32%	-6.73%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	16.98%	23.19%	-6.21%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	18.01%	23.67%	-5.66%

BSPAX vs. BDBKX - Expense Ratio Comparison

BSPAX has a 0.35% expense ratio, which is higher than BDBKX's 0.07% expense ratio.

Dividends

BSPAX vs. BDBKX - Dividend Comparison

BSPAX's dividend yield for the trailing twelve months is around 1.37%, less than BDBKX's 2.56% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
BDBKX iShares Russell 2000 Small-Cap Index Fund Class K	2.56%	3.17%	4.84%	2.96%	1.76%	7.67%	1.45%	3.47%	4.29%	3.18%	4.62%	3.64%
BSPAX iShares S&P 500 Index Fund Investor A Shares	1.37%	1.43%	1.12%	1.22%	1.67%	1.52%	1.37%	1.70%	1.74%	1.40%	1.62%	2.17%

Frequently Asked Questions

Can I hold both BSPAX and BDBKX in my portfolio?

BSPAX and BDBKX have a correlation of 0.78, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, BSPAX or BDBKX?

BDBKX has higher volatility (3.70%) compared to BSPAX (3.37%). In terms of maximum drawdown, BSPAX dropped -33.76% vs BDBKX's -41.66%.

Which has better risk-adjusted returns?

BDBKX currently has the higher Sharpe Ratio (1.83 vs 1.55), 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.