AFIFX vs. VIIIX

Last updated Jun 25, 2026

AFIFX (American Funds Fundamental Investors Class F-1) and VIIIX (Vanguard Institutional Index Fund Institutional Plus Shares) are both mutual funds - AFIFX is a Large Cap Blend Equities fund actively managed by American Funds, while VIIIX is a S&P 500 fund tracking the S&P 500 Index. AFIFX is actively managed, while VIIIX is passively managed. Over the past 10 years, AFIFX returned 14.91%/yr vs 15.70%/yr for VIIIX. With a 0.96 correlation, they move nearly in lockstep. AFIFX charges 0.64%/yr vs 0.02%/yr for VIIIX.

Performance

AFIFX vs. VIIIX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in American Funds Fundamental Investors Class F-1 (AFIFX) 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, AFIFX achieves a 12.23% return, which is significantly higher than VIIIX's 8.21% return. Over the past 10 years, AFIFX has underperformed VIIIX with an annualized return of 14.91%, while VIIIX has yielded a comparatively higher 15.70% annualized return.

AFIFX

• 1D: -1.73%
• 1M: 0.13%
• YTD: 12.23%
• 6M: 11.48%
• 1Y: 27.16%
• 3Y*: 24.45%
• 5Y*: 13.99%
• 10Y*: 14.91%

VIIIX

• 1D: -1.44%
• 1M: -1.34%
• YTD: 8.21%
• 6M: 6.88%
• 1Y: 22.35%
• 3Y*: 21.22%
• 5Y*: 13.28%
• 10Y*: 15.70%

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

AFIFX vs. VIIIX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
AFIFX American Funds Fundamental Investors Class F-1	12.23%	24.12%	22.68%	25.78%	-16.69%	22.36%	14.85%	27.00%	-8.19%	22.70%
VIIIX Vanguard Institutional Index Fund Institutional Plus Shares	8.21%	17.87%	26.29%	25.79%	-18.14%	28.69%	18.41%	31.48%	-4.41%	21.82%

Correlation

The correlation between AFIFX and VIIIX 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	0.95
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 2, 2002	0.96

The correlation between AFIFX and VIIIX has been stable across timeframes, ranging from 0.94 to 0.96 - a consistent structural relationship.

Return for Risk

AFIFX vs. VIIIX — Risk / Return Rank

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

AFIFX

AFIFX Risk / Return Rank: 60
AFIFX Sharpe Ratio Rank: 58
AFIFX Sortino Ratio Rank: 54
AFIFX Omega Ratio Rank: 54
AFIFX Calmar Ratio Rank: 60
AFIFX Martin Ratio Rank: 72

VIIIX

VIIIX Risk / Return Rank: 52
VIIIX Sharpe Ratio Rank: 49
VIIIX Sortino Ratio Rank: 44
VIIIX Omega Ratio Rank: 47
VIIIX Calmar Ratio Rank: 53
VIIIX Martin Ratio Rank: 66

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.

AFIFX vs. VIIIX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for American Funds Fundamental Investors Class F-1 (AFIFX) 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.

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.

	AFIFX	VIIIX	Difference
Sharpe ratio: Return per unit of total volatility	1.99	1.90	+0.09
Sortino ratio: Return per unit of downside risk	2.70	2.59	+0.11
Omega ratio: Gain probability vs. loss probability	1.36	1.34	+0.01
Calmar ratio: Return relative to maximum drawdown	2.74	2.68	+0.07
Martin ratio: Return relative to average drawdown	12.32	12.03	+0.29

AFIFX vs. VIIIX - Sharpe Ratio Comparison

The current AFIFX Sharpe Ratio is 1.99, which is comparable to the VIIIX Sharpe Ratio of 1.90. The chart below compares the historical Sharpe Ratios of AFIFX 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.

Drawdowns

AFIFX vs. VIIIX - Drawdown Comparison

The maximum AFIFX drawdown since its inception was -53.25%, roughly equal to the maximum VIIIX drawdown of -55.18%. Use the drawdown chart below to compare losses from any high point for AFIFX and VIIIX.

Drawdown Indicators

	AFIFX	VIIIX	Difference
Max Drawdown Largest peak-to-trough decline	-53.25%	-55.18%	+1.93%
Max Drawdown (1Y) Largest decline over 1 year	-10.67%	-8.90%	-1.77%
Max Drawdown (3Y) Largest decline over 3 years	-17.99%	-18.75%	+0.76%
Max Drawdown (5Y) Largest decline over 5 years	-25.11%	-24.50%	-0.61%
Max Drawdown (10Y) Largest decline over 10 years	-33.92%	-33.79%	-0.13%
Current Drawdown Current decline from peak	-2.49%	-3.13%	+0.64%
Average Drawdown Average peak-to-trough decline	-7.36%	-10.00%	+2.64%
Ulcer Index Depth and duration of drawdowns from previous peaks	2.37%	1.98%	+0.39%

Volatility

AFIFX vs. VIIIX - Volatility Comparison

American Funds Fundamental Investors Class F-1 (AFIFX) has a higher volatility of 5.88% compared to Vanguard Institutional Index Fund Institutional Plus Shares (VIIIX) at 4.90%. This indicates that AFIFX's price experiences larger fluctuations and is considered to be riskier than VIIIX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	AFIFX	VIIIX	Difference
Volatility (1M) Calculated over the trailing 1-month period	5.88%	4.90%	+0.98%
Volatility (6M) Calculated over the trailing 6-month period	11.82%	9.93%	+1.89%
Volatility (1Y) Calculated over the trailing 1-year period	14.73%	12.57%	+2.16%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	16.95%	17.00%	-0.05%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	17.75%	18.08%	-0.33%

AFIFX vs. VIIIX - Expense Ratio Comparison

AFIFX has a 0.64% expense ratio, which is higher than VIIIX's 0.02% expense ratio.

Dividends

AFIFX vs. VIIIX - Dividend Comparison

AFIFX's dividend yield for the trailing twelve months is around 7.36%, more than VIIIX's 2.49% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
AFIFX American Funds Fundamental Investors Class F-1	7.36%	8.48%	8.84%	5.76%	4.92%	10.91%	2.57%	6.86%	9.21%	7.21%	4.65%	6.01%
VIIIX Vanguard Institutional Index Fund Institutional Plus Shares	2.49%	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 AFIFX and VIIIX in my portfolio?

With a correlation of 0.94, AFIFX and VIIIX 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, AFIFX or VIIIX?

AFIFX has higher volatility (5.88%) compared to VIIIX (4.90%). In terms of maximum drawdown, AFIFX dropped -53.25% vs VIIIX's -55.18%.

Which has better risk-adjusted returns?

AFIFX currently has the higher Sharpe Ratio (1.99 vs 1.90), 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.