BKTSX vs. AFIFX

Last updated Jun 4, 2026

BKTSX (iShares Total U.S. Stock Market Index Fund Class K) and AFIFX (American Funds Fundamental Investors Class F-1) are both Large Cap Blend Equities funds. BKTSX is passively managed, while AFIFX is actively managed. Over the past 10 years, BKTSX returned 15.13%/yr vs 14.83%/yr for AFIFX. With a 0.96 correlation, they move nearly in lockstep. BKTSX charges 0.02%/yr vs 0.64%/yr for AFIFX.

Performance

BKTSX vs. AFIFX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in iShares Total U.S. Stock Market Index Fund Class K (BKTSX) and American Funds Fundamental Investors Class F-1 (AFIFX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, BKTSX achieves a 11.73% return, which is significantly lower than AFIFX's 15.10% return. Both investments have delivered pretty close results over the past 10 years, with BKTSX having a 15.13% annualized return and AFIFX not far behind at 14.83%.

BKTSX

• 1D: 0.23%
• 1M: 5.68%
• YTD: 11.73%
• 6M: 11.61%
• 1Y: 28.67%
• 3Y*: 22.30%
• 5Y*: 13.12%
• 10Y*: 15.13%

AFIFX

• 1D: 0.00%
• 1M: 5.89%
• YTD: 15.10%
• 6M: 16.10%
• 1Y: 34.46%
• 3Y*: 26.02%
• 5Y*: 14.84%
• 10Y*: 14.83%

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

BKTSX vs. AFIFX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
BKTSX iShares Total U.S. Stock Market Index Fund Class K	11.73%	17.15%	23.83%	26.02%	-19.05%	25.56%	20.82%	31.12%	-5.37%	21.02%
AFIFX American Funds Fundamental Investors Class F-1	15.10%	24.12%	22.68%	25.78%	-16.69%	22.36%	14.85%	27.00%	-8.19%	22.70%

Correlation

The correlation between BKTSX and AFIFX is 0.93, 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	0.93
Correlation (3Y) Calculated over the trailing 3-year period	0.95
Correlation (5Y) Calculated over the trailing 5-year period	0.96
Correlation (10Y) Calculated over the trailing 10-year period	0.96
Correlation (All Time) Calculated using the full available price history since Jan 5, 2016	0.96

The correlation between BKTSX and AFIFX has been stable across timeframes, ranging from 0.93 to 0.96 - a consistent structural relationship.

Return for Risk

BKTSX vs. AFIFX — Risk / Return Rank

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

BKTSX

BKTSX Risk / Return Rank: 70
BKTSX Sharpe Ratio Rank: 70
BKTSX Sortino Ratio Rank: 63
BKTSX Omega Ratio Rank: 62
BKTSX Calmar Ratio Rank: 73
BKTSX Martin Ratio Rank: 82

AFIFX

AFIFX Risk / Return Rank: 74
AFIFX Sharpe Ratio Rank: 79
AFIFX Sortino Ratio Rank: 69
AFIFX Omega Ratio Rank: 69
AFIFX Calmar Ratio Rank: 73
AFIFX Martin Ratio Rank: 82

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.

BKTSX vs. AFIFX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for iShares Total U.S. Stock Market Index Fund Class K (BKTSX) and American Funds Fundamental Investors Class F-1 (AFIFX). 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.

	BKTSX	AFIFX	Difference
Sharpe ratio Return per unit of total volatility	2.44	2.58	-0.14
Sortino ratio Return per unit of downside risk	3.33	3.46	-0.12
Omega ratio Gain probability vs. loss probability	1.44	1.46	-0.03
Calmar ratio Return relative to maximum drawdown	3.34	3.32	+0.02
Martin ratio Return relative to average drawdown	15.37	15.36	+0.01
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

BKTSX vs. AFIFX - Sharpe Ratio Comparison

The current BKTSX Sharpe Ratio is 2.44, which is comparable to the AFIFX Sharpe Ratio of 2.58. The chart below compares the historical Sharpe Ratios of BKTSX and AFIFX, calculated using daily returns over the previous 12 months. A higher Sharpe Ratio indicates better risk-adjusted performance relative to the risk-free rate.

Sharpe Ratios by Period

	BKTSX	AFIFX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	2.44	2.58	-0.14
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.76	0.89	-0.13
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.82	0.84	-0.02
Sharpe Ratio (All Time) Calculated using the full available price history	0.83	0.59	+0.24

Drawdowns

BKTSX vs. AFIFX - Drawdown Comparison

The maximum BKTSX drawdown since its inception was -34.97%, smaller than the maximum AFIFX drawdown of -53.25%. Use the drawdown chart below to compare losses from any high point for BKTSX and AFIFX.

Drawdown Indicators

	BKTSX	AFIFX	Difference
Max Drawdown Largest peak-to-trough decline	-34.97%	-53.25%	+18.28%
Max Drawdown (1Y) Largest decline over 1 year	-8.87%	-10.67%	+1.80%
Max Drawdown (3Y) Largest decline over 3 years	-19.29%	-17.99%	-1.30%
Max Drawdown (5Y) Largest decline over 5 years	-24.98%	-25.11%	+0.13%
Max Drawdown (10Y) Largest decline over 10 years	-34.97%	-33.92%	-1.05%
Current Drawdown Current decline from peak	0.00%	0.00%	0.00%
Average Drawdown Average peak-to-trough decline	-4.53%	-7.37%	+2.84%
Ulcer Index Depth and duration of drawdowns from previous peaks	1.93%	2.30%	-0.37%

Volatility

BKTSX vs. AFIFX - Volatility Comparison

The current volatility for iShares Total U.S. Stock Market Index Fund Class K (BKTSX) is 2.94%, while American Funds Fundamental Investors Class F-1 (AFIFX) has a volatility of 3.69%. This indicates that BKTSX experiences smaller price fluctuations and is considered to be less risky than AFIFX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	BKTSX	AFIFX	Difference
Volatility (1M) Calculated over the trailing 1-month period	2.94%	3.69%	-0.75%
Volatility (6M) Calculated over the trailing 6-month period	9.13%	10.82%	-1.69%
Volatility (1Y) Calculated over the trailing 1-year period	12.15%	13.74%	-1.59%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	17.36%	16.79%	+0.57%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	18.41%	17.73%	+0.68%

BKTSX vs. AFIFX - Expense Ratio Comparison

BKTSX has a 0.02% expense ratio, which is lower than AFIFX's 0.64% expense ratio.

Dividends

BKTSX vs. AFIFX - Dividend Comparison

BKTSX's dividend yield for the trailing twelve months is around 1.04%, less than AFIFX's 7.38% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
AFIFX American Funds Fundamental Investors Class F-1	7.38%	8.48%	8.84%	5.76%	4.92%	10.91%	2.57%	6.86%	9.21%	7.21%	4.65%	6.01%
BKTSX iShares Total U.S. Stock Market Index Fund Class K	1.04%	1.14%	1.27%	1.46%	1.64%	1.58%	1.51%	2.15%	2.49%	2.17%	1.54%	0.00%

Frequently Asked Questions

Can I hold both BKTSX and AFIFX in my portfolio?

With a correlation of 0.93, BKTSX and AFIFX 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.

Which is riskier, BKTSX or AFIFX?

AFIFX has higher volatility (3.69%) compared to BKTSX (2.94%). In terms of maximum drawdown, BKTSX dropped -34.97% vs AFIFX's -53.25%.

Which has better risk-adjusted returns?

AFIFX currently has the higher Sharpe Ratio (2.58 vs 2.44), 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.