FZFLX vs. FXAIX

Last updated Aug 1, 2026

FZFLX (Fidelity SAI Small-Mid Cap 500 Index Fund) and FXAIX (Fidelity 500 Index Fund) are both mutual funds - FZFLX is a Mid Cap Blend Equities fund managed by Fidelity, while FXAIX is a S&P 500 fund tracking the S&P 500 Index. Over the past 10 years, FZFLX returned 13.03%/yr vs 15.00%/yr for FXAIX. Their correlation of 0.86 means they have usually moved in the same direction. FZFLX charges 0.05%/yr vs 0.02%/yr for FXAIX.

Performance

FZFLX vs. FXAIX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Fidelity SAI Small-Mid Cap 500 Index Fund (FZFLX) and Fidelity 500 Index Fund (FXAIX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, FZFLX achieves a 26.12% return, which is significantly higher than FXAIX's 9.35% return. Over the past 10 years, FZFLX has underperformed FXAIX with an annualized return of 13.03%, while FXAIX has yielded a comparatively higher 15.00% annualized return.

FZFLX

• 1D: 3.67%
• 1M: -3.42%
• 6M: 18.20%
• YTD: 26.12%
• 1Y: 36.06%
• 3Y*: 18.61%
• 5Y*: 10.68%
• 10Y*: 13.03%
• ALL TIME*: 12.39%

FXAIX

• 1D: 1.66%
• 1M: -0.56%
• 6M: 7.79%
• YTD: 9.35%
• 1Y: 20.63%
• 3Y*: 19.03%
• 5Y*: 12.68%
• 10Y*: 15.00%
• ALL TIME*: 13.89%

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

Liquidity Comparison

Position	Avg. Volume Value (2W)	Avg. Volume Value (1M)	Avg. Volume Value (3M)
FXAIX Fidelity 500 Index Fund	$0.00	$0.00	$0.00
FZFLX Fidelity SAI Small-Mid Cap 500 Index Fund	$0.00	$0.00	$0.00

FZFLX vs. FXAIX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
FZFLX Fidelity SAI Small-Mid Cap 500 Index Fund	26.12%	10.76%	15.52%	17.75%	-15.62%	20.40%	19.78%	31.96%	-9.25%	18.41%
FXAIX Fidelity 500 Index Fund	9.35%	17.84%	25.01%	26.29%	-18.14%	28.71%	18.42%	31.48%	-4.43%	21.82%

Correlation

The correlation between FZFLX and FXAIX is 0.76, which is moderate. They have sometimes moved together and sometimes differently, sharing some price drivers without tracking each other closely.

	Correlation
Correlation (1Y) Focuses on recent behavior, but can change the most.	0.76
Correlation (3Y) Balances recent behavior with more history.	0.78
Correlation (5Y) Shows whether the relationship held over a longer period.	0.84
Correlation (10Y) Provides a long-term view across more market conditions.	0.85
Correlation (All Time) Calculated using the full available price history since Aug 20, 2015	0.86

The correlation between FZFLX and FXAIX shifts across timeframes, from 0.76 (1 year) to 0.86 (all time), reflecting how their relationship changes across market environments.

Return for Risk

FZFLX vs. FXAIX — Risk / Return Rank

Compare historical risk-adjusted metric ranks over the past 12 months.

FZFLX

FZFLX Risk / Return Rank: 68
FZFLX Sharpe Ratio Rank: 59
FZFLX Sortino Ratio Rank: 58
FZFLX Omega Ratio Rank: 55
FZFLX Calmar Ratio Rank: 84
FZFLX Martin Ratio Rank: 84

FXAIX

FXAIX Risk / Return Rank: 64
FXAIX Sharpe Ratio Rank: 61
FXAIX Sortino Ratio Rank: 58
FXAIX Omega Ratio Rank: 59
FXAIX Calmar Ratio Rank: 65
FXAIX Martin Ratio Rank: 76

The rank (0–100) uses a weighted average of the Sharpe, Sortino, Omega, Calmar, and Martin percentile ranks for the trailing 12 months. Higher means stronger historical risk-adjusted performance within the peer group.

FZFLX vs. FXAIX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Fidelity SAI Small-Mid Cap 500 Index Fund (FZFLX) and Fidelity 500 Index Fund (FXAIX). 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.

	FZFLX	FXAIX	Difference
Sharpe ratio: Return per unit of total volatility	1.44	1.43	+0.01
Sortino ratio: Return per unit of downside risk	2.04	2.00	+0.04
Omega ratio: Gain probability vs. loss probability	1.25	1.26	0.00
Calmar ratio: Return relative to maximum drawdown	2.84	2.06	+0.77
Martin ratio: Return relative to average drawdown	10.39	8.86	+1.53

FZFLX vs. FXAIX - Sharpe Ratio Comparison

The current FZFLX Sharpe Ratio is 1.44, which is comparable to the FXAIX Sharpe Ratio of 1.43. The chart below compares the historical Sharpe Ratios of FZFLX and FXAIX, 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

FZFLX vs. FXAIX - Drawdown Comparison

The maximum FZFLX drawdown since its inception was -42.03%, which is greater than FXAIX's maximum drawdown of -33.79%. Use the drawdown chart below to compare losses from any high point for FZFLX and FXAIX.

Drawdown Indicators

	FZFLX	FXAIX	Difference
Max Drawdown Largest peak-to-trough decline	-42.03%	-33.79%	-8.24%
Max Drawdown (1Y) Largest decline over 1 year	-11.67%	-8.89%	-2.78%
Max Drawdown (3Y) Largest decline over 3 years	-22.29%	-18.76%	-3.53%
Max Drawdown (5Y) Largest decline over 5 years	-24.77%	-24.50%	-0.27%
Max Drawdown (10Y) Largest decline over 10 years	-42.03%	-33.79%	-8.24%
Current Drawdown Current decline from peak	-8.43%	-2.11%	-6.32%
Average Drawdown Average peak-to-trough decline	-5.72%	-3.77%	-1.95%
Ulcer Index Depth and duration of drawdowns from previous peaks	3.19%	2.07%	+1.12%

Volatility

FZFLX vs. FXAIX - Volatility Comparison

Fidelity SAI Small-Mid Cap 500 Index Fund (FZFLX) has a higher volatility of 7.98% compared to Fidelity 500 Index Fund (FXAIX) at 3.44%. This indicates that FZFLX's price experiences larger fluctuations and is considered to be riskier than FXAIX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	FZFLX	FXAIX	Difference
Volatility (1M) Calculated over the trailing 1-month period	7.98%	3.44%	+4.54%
Volatility (6M) Calculated over the trailing 6-month period	20.12%	10.09%	+10.03%
Volatility (1Y) Calculated over the trailing 1-year period	23.08%	12.86%	+10.22%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	21.52%	17.03%	+4.49%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	21.27%	18.07%	+3.20%

FZFLX vs. FXAIX - Expense Ratio Comparison

FZFLX has a 0.05% expense ratio, which is higher than FXAIX'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

FZFLX vs. FXAIX - Dividend Comparison

FZFLX's dividend yield for the trailing twelve months is around 45.81%, more than FXAIX's 1.07% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
FXAIX Fidelity 500 Index Fund	1.07%	1.11%	1.25%	1.45%	1.69%	1.22%	1.60%	2.06%	2.72%	1.97%	2.52%	2.83%
FZFLX Fidelity SAI Small-Mid Cap 500 Index Fund	45.81%	57.77%	10.20%	2.35%	79.79%	50.77%	7.19%	6.49%	7.69%	1.68%	0.93%	0.67%

Frequently Asked Questions

Can I hold both FZFLX and FXAIX in my portfolio?

FZFLX and FXAIX have a correlation of 0.76, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, FZFLX or FXAIX?

FZFLX has higher volatility (7.98%) compared to FXAIX (3.44%). In terms of maximum drawdown, FZFLX dropped -42.03% vs FXAIX's -33.79%.

Which has better risk-adjusted returns?

FZFLX currently has the higher Sharpe Ratio (1.44 vs 1.43), 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.