AFMFX vs. VIIIX

Last updated Jun 4, 2026

AFMFX (American Funds American Mutual Fund Class F-3) and VIIIX (Vanguard Institutional Index Fund Institutional Plus Shares) are both mutual funds - AFMFX is a Large Cap Value Equities fund managed by American Funds, while VIIIX is a S&P 500 fund tracking the S&P 500 Index. Over the past 5 years, AFMFX returned 10.36%/yr vs 14.42%/yr for VIIIX. Their correlation of 0.90 suggests significant overlap in exposure. AFMFX charges 0.27%/yr vs 0.02%/yr for VIIIX.

Performance

AFMFX vs. VIIIX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in American Funds American Mutual Fund Class F-3 (AFMFX) and Vanguard Institutional Index Fund Institutional Plus Shares (VIIIX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, AFMFX achieves a 6.78% return, which is significantly lower than VIIIX's 11.70% return.

AFMFX

• 1D: 0.62%
• 1M: 2.98%
• YTD: 6.78%
• 6M: 7.02%
• 1Y: 17.61%
• 3Y*: 15.85%
• 5Y*: 10.36%
• 10Y*: —

VIIIX

• 1D: 0.13%
• 1M: 5.80%
• YTD: 11.70%
• 6M: 11.74%
• 1Y: 28.99%
• 3Y*: 23.17%
• 5Y*: 14.42%
• 10Y*: 15.74%

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

AFMFX vs. VIIIX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
AFMFX American Funds American Mutual Fund Class F-3	6.78%	16.43%	15.30%	9.77%	-4.19%	23.64%	5.04%	21.90%	-1.98%	11.75%
VIIIX Vanguard Institutional Index Fund Institutional Plus Shares	11.70%	17.87%	26.29%	25.79%	-18.14%	28.69%	18.41%	31.48%	-4.41%	14.15%

Correlation

The correlation between AFMFX and VIIIX is 0.80, 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	0.80
Correlation (3Y) Calculated over the trailing 3-year period	0.83
Correlation (5Y) Calculated over the trailing 5-year period	0.87
Correlation (All Time) Calculated using the full available price history since Mar 20, 2017	0.90

The correlation between AFMFX and VIIIX has been stable across timeframes, ranging from 0.80 to 0.90 - a consistent structural relationship.

Return for Risk

AFMFX vs. VIIIX — Risk / Return Rank

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

AFMFX

AFMFX Risk / Return Rank: 42
AFMFX Sharpe Ratio Rank: 43
AFMFX Sortino Ratio Rank: 41
AFMFX Omega Ratio Rank: 42
AFMFX Calmar Ratio Rank: 37
AFMFX Martin Ratio Rank: 44

VIIIX

VIIIX Risk / Return Rank: 73
VIIIX Sharpe Ratio Rank: 76
VIIIX Sortino Ratio Rank: 67
VIIIX Omega Ratio Rank: 67
VIIIX Calmar Ratio Rank: 74
VIIIX Martin Ratio Rank: 83

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.

AFMFX vs. VIIIX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for American Funds American Mutual Fund Class F-3 (AFMFX) and Vanguard Institutional Index Fund Institutional Plus Shares (VIIIX). 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.

	AFMFX	VIIIX	Difference
Sharpe ratio: Return per unit of total volatility	1.92	2.52	-0.60
Sortino ratio: Return per unit of downside risk	2.68	3.42	-0.74
Omega ratio: Gain probability vs. loss probability	1.35	1.46	-0.11
Calmar ratio: Return relative to maximum drawdown	2.31	3.36	-1.05
Martin ratio: Return relative to average drawdown	9.27	15.69	-6.43
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

AFMFX vs. VIIIX - Sharpe Ratio Comparison

The current AFMFX Sharpe Ratio is 1.92, which is comparable to the VIIIX Sharpe Ratio of 2.52. The chart below compares the historical Sharpe Ratios of AFMFX and VIIIX, 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

	AFMFX	VIIIX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	1.92	2.52	-0.60
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.83	0.86	-0.02
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	—	0.87	—
Sharpe Ratio (All Time) Calculated using the full available price history	0.76	0.50	+0.27

Drawdowns

AFMFX vs. VIIIX - Drawdown Comparison

The maximum AFMFX drawdown since its inception was -29.79%, smaller than the maximum VIIIX drawdown of -55.18%. Use the drawdown chart below to compare losses from any high point for AFMFX and VIIIX.

Drawdown Indicators

	AFMFX	VIIIX	Difference
Max Drawdown Largest peak-to-trough decline	-29.79%	-55.18%	+25.39%
Max Drawdown (1Y) Largest decline over 1 year	-7.90%	-8.90%	+1.00%
Max Drawdown (3Y) Largest decline over 3 years	-12.91%	-18.75%	+5.84%
Max Drawdown (5Y) Largest decline over 5 years	-15.16%	-24.50%	+9.34%
Max Drawdown (10Y) Largest decline over 10 years	—	-33.79%	—
Current Drawdown Current decline from peak	0.00%	0.00%	0.00%
Average Drawdown Average peak-to-trough decline	-2.92%	-10.02%	+7.10%
Ulcer Index Depth and duration of drawdowns from previous peaks	1.96%	1.90%	+0.06%

Volatility

AFMFX vs. VIIIX - Volatility Comparison

The current volatility for American Funds American Mutual Fund Class F-3 (AFMFX) is 2.36%, while Vanguard Institutional Index Fund Institutional Plus Shares (VIIIX) has a volatility of 2.83%. This indicates that AFMFX experiences smaller price fluctuations and is considered to be less risky than VIIIX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	AFMFX	VIIIX	Difference
Volatility (1M) Calculated over the trailing 1-month period	2.36%	2.83%	-0.47%
Volatility (6M) Calculated over the trailing 6-month period	7.36%	8.97%	-1.61%
Volatility (1Y) Calculated over the trailing 1-year period	9.50%	11.86%	-2.36%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	12.50%	16.89%	-4.39%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	14.50%	18.06%	-3.56%

AFMFX vs. VIIIX - Expense Ratio Comparison

AFMFX has a 0.27% expense ratio, which is higher than VIIIX's 0.02% 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

AFMFX vs. VIIIX - Dividend Comparison

AFMFX's dividend yield for the trailing twelve months is around 7.40%, more than VIIIX's 2.41% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
AFMFX American Funds American Mutual Fund Class F-3	7.40%	7.86%	6.60%	4.06%	5.20%	3.58%	2.22%	4.89%	6.75%	6.25%	0.00%	0.00%
VIIIX Vanguard Institutional Index Fund Institutional Plus Shares	2.41%	2.11%	3.66%	2.66%	3.39%	4.79%	3.07%	2.86%	2.45%	1.84%	2.38%	2.47%

Frequently Asked Questions

Can I hold both AFMFX and VIIIX in my portfolio?

AFMFX and VIIIX have a correlation of 0.80, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, AFMFX or VIIIX?

VIIIX has higher volatility (2.83%) compared to AFMFX (2.36%). In terms of maximum drawdown, AFMFX dropped -29.79% vs VIIIX's -55.18%.

Which has better risk-adjusted returns?

VIIIX currently has the higher Sharpe Ratio (2.52 vs 1.92), 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.