FIDEX vs. VFFSX

Last updated Jun 4, 2026

FIDEX (Fidelity SAI Sustainable U.S. Equity Fund) and VFFSX (Vanguard 500 Index Fund Institutional Select Shares) are both Large Cap Blend Equities funds. Over the past 3 years, FIDEX returned 20.90%/yr vs 22.76%/yr for VFFSX. With a 0.97 correlation, they move nearly in lockstep. FIDEX charges 0.56%/yr vs 0.01%/yr for VFFSX.

Performance

FIDEX vs. VFFSX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Fidelity SAI Sustainable U.S. Equity Fund (FIDEX) and Vanguard 500 Index Fund Institutional Select Shares (VFFSX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, FIDEX achieves a 13.79% return, which is significantly higher than VFFSX's 11.71% return.

FIDEX

• 1D: 0.42%
• 1M: 6.15%
• YTD: 13.79%
• 6M: 13.98%
• 1Y: 32.88%
• 3Y*: 20.90%
• 5Y*: —
• 10Y*: —

VFFSX

• 1D: 0.13%
• 1M: 5.80%
• YTD: 11.71%
• 6M: 11.74%
• 1Y: 28.99%
• 3Y*: 22.76%
• 5Y*: 14.27%
• 10Y*: —

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

FIDEX vs. VFFSX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022
FIDEX Fidelity SAI Sustainable U.S. Equity Fund	13.79%	15.80%	21.44%	24.99%	-8.88%
VFFSX Vanguard 500 Index Fund Institutional Select Shares	11.71%	17.87%	25.00%	26.28%	-9.57%

Correlation

The correlation between FIDEX and VFFSX is 0.95 - these two move nearly in lockstep. At this level, holding both provides almost no diversification benefit. If you already own one, adding the other does little to reduce portfolio risk.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	0.95
Correlation (3Y) Calculated over the trailing 3-year period	0.95
Correlation (All Time) Calculated using the full available price history since Apr 26, 2022	0.97

The correlation between FIDEX and VFFSX has been stable across timeframes, ranging from 0.95 to 0.97 - a consistent structural relationship.

Return for Risk

FIDEX vs. VFFSX — Risk / Return Rank

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

FIDEX

FIDEX Risk / Return Rank: 70
FIDEX Sharpe Ratio Rank: 69
FIDEX Sortino Ratio Rank: 63
FIDEX Omega Ratio Rank: 60
FIDEX Calmar Ratio Rank: 73
FIDEX Martin Ratio Rank: 84

VFFSX

VFFSX Risk / Return Rank: 73
VFFSX Sharpe Ratio Rank: 76
VFFSX Sortino Ratio Rank: 67
VFFSX Omega Ratio Rank: 67
VFFSX Calmar Ratio Rank: 74
VFFSX 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.

FIDEX vs. VFFSX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Fidelity SAI Sustainable U.S. Equity Fund (FIDEX) and Vanguard 500 Index Fund Institutional Select Shares (VFFSX). 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.

	FIDEX	VFFSX	Difference
Sharpe ratio: Return per unit of total volatility	2.43	2.52	-0.09
Sortino ratio: Return per unit of downside risk	3.33	3.42	-0.10
Omega ratio: Gain probability vs. loss probability	1.43	1.46	-0.03
Calmar ratio: Return relative to maximum drawdown	3.33	3.36	-0.03
Martin ratio: Return relative to average drawdown	15.95	15.70	+0.25
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

FIDEX vs. VFFSX - Sharpe Ratio Comparison

The current FIDEX Sharpe Ratio is 2.43, which is comparable to the VFFSX Sharpe Ratio of 2.52. The chart below compares the historical Sharpe Ratios of FIDEX and VFFSX, 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

	FIDEX	VFFSX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	2.43	2.52	-0.09
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	—	0.85	—
Sharpe Ratio (All Time) Calculated using the full available price history	0.86	0.86	0.00

Drawdowns

FIDEX vs. VFFSX - Drawdown Comparison

The maximum FIDEX drawdown since its inception was -21.90%, smaller than the maximum VFFSX drawdown of -33.82%. Use the drawdown chart below to compare losses from any high point for FIDEX and VFFSX.

Drawdown Indicators

	FIDEX	VFFSX	Difference
Max Drawdown Largest peak-to-trough decline	-21.90%	-33.82%	+11.92%
Max Drawdown (1Y) Largest decline over 1 year	-10.13%	-8.90%	-1.23%
Max Drawdown (3Y) Largest decline over 3 years	-21.90%	-18.75%	-3.15%
Max Drawdown (5Y) Largest decline over 5 years	—	-24.51%	—
Current Drawdown Current decline from peak	0.00%	0.00%	0.00%
Average Drawdown Average peak-to-trough decline	-3.70%	-4.50%	+0.80%
Ulcer Index Depth and duration of drawdowns from previous peaks	2.11%	1.90%	+0.21%

Volatility

FIDEX vs. VFFSX - Volatility Comparison

Fidelity SAI Sustainable U.S. Equity Fund (FIDEX) has a higher volatility of 3.92% compared to Vanguard 500 Index Fund Institutional Select Shares (VFFSX) at 2.83%. This indicates that FIDEX's price experiences larger fluctuations and is considered to be riskier than VFFSX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	FIDEX	VFFSX	Difference
Volatility (1M) Calculated over the trailing 1-month period	3.92%	2.83%	+1.09%
Volatility (6M) Calculated over the trailing 6-month period	10.80%	8.98%	+1.82%
Volatility (1Y) Calculated over the trailing 1-year period	13.86%	11.86%	+2.00%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	18.47%	16.90%	+1.57%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	18.47%	18.41%	+0.06%

FIDEX vs. VFFSX - Expense Ratio Comparison

FIDEX has a 0.56% expense ratio, which is higher than VFFSX's 0.01% expense ratio.

Dividends

FIDEX vs. VFFSX - Dividend Comparison

FIDEX's dividend yield for the trailing twelve months is around 1.38%, more than VFFSX's 1.03% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017
FIDEX Fidelity SAI Sustainable U.S. Equity Fund	1.38%	1.64%	1.87%	0.46%	0.63%	0.00%	0.00%	0.00%	0.00%	0.00%
VFFSX Vanguard 500 Index Fund Institutional Select Shares	1.03%	1.14%	1.24%	1.46%	1.70%	1.61%	1.56%	2.15%	2.09%	1.81%

Frequently Asked Questions

Can I hold both FIDEX and VFFSX in my portfolio?

With a correlation of 0.95, FIDEX and VFFSX 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, FIDEX or VFFSX?

FIDEX has higher volatility (3.92%) compared to VFFSX (2.83%). In terms of maximum drawdown, FIDEX dropped -21.90% vs VFFSX's -33.82%.

Which has better risk-adjusted returns?

VFFSX currently has the higher Sharpe Ratio (2.52 vs 2.43), 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.