FLAPX vs. FSMAX

Last updated Jun 4, 2026

FLAPX (Fidelity Flex Mid Cap Index Fund) and FSMAX (Fidelity Extended Market Index Fund) are both mutual funds - FLAPX is a Mid Cap Blend Equities fund managed by Fidelity, while FSMAX is a Mid Cap Growth Equities fund managed by Fidelity. Over the past 5 years, FLAPX returned 9.56%/yr vs 6.91%/yr for FSMAX. With a 0.96 correlation, they move nearly in lockstep. FLAPX charges 0.00%/yr vs 0.04%/yr for FSMAX.

Performance

FLAPX vs. FSMAX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Fidelity Flex Mid Cap Index Fund (FLAPX) and Fidelity Extended Market Index Fund (FSMAX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

The year-to-date returns for both stocks are quite close, with FLAPX having a 15.19% return and FSMAX slightly lower at 14.89%.

FLAPX

• 1D: 0.37%
• 1M: 3.60%
• YTD: 15.19%
• 6M: 15.35%
• 1Y: 28.95%
• 3Y*: 19.67%
• 5Y*: 9.56%
• 10Y*: —

FSMAX

• 1D: 1.07%
• 1M: 5.80%
• YTD: 14.89%
• 6M: 13.61%
• 1Y: 30.08%
• 3Y*: 20.13%
• 5Y*: 6.91%
• 10Y*: 12.17%

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

FLAPX vs. FSMAX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
FLAPX Fidelity Flex Mid Cap Index Fund	15.19%	14.33%	15.30%	17.28%	-17.28%	22.59%	17.30%	30.56%	-9.10%	14.01%
FSMAX Fidelity Extended Market Index Fund	14.89%	11.40%	16.99%	25.36%	-26.44%	12.41%	32.28%	28.01%	-9.44%	14.70%

Correlation

The correlation between FLAPX and FSMAX 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	0.96
Correlation (5Y) Calculated over the trailing 5-year period	0.96
Correlation (All Time) Calculated using the full available price history since Mar 10, 2017	0.96

The correlation between FLAPX and FSMAX has been stable across timeframes, ranging from 0.95 to 0.96 - a consistent structural relationship.

Return for Risk

FLAPX vs. FSMAX — Risk / Return Rank

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

FLAPX

FLAPX Risk / Return Rank: 54
FLAPX Sharpe Ratio Rank: 45
FLAPX Sortino Ratio Rank: 45
FLAPX Omega Ratio Rank: 42
FLAPX Calmar Ratio Rank: 72
FLAPX Martin Ratio Rank: 67

FSMAX

FSMAX Risk / Return Rank: 47
FSMAX Sharpe Ratio Rank: 41
FSMAX Sortino Ratio Rank: 39
FSMAX Omega Ratio Rank: 37
FSMAX Calmar Ratio Rank: 66
FSMAX Martin Ratio Rank: 54

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.

FLAPX vs. FSMAX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Fidelity Flex Mid Cap Index Fund (FLAPX) and Fidelity Extended Market Index Fund (FSMAX). 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.

	FLAPX	FSMAX	Difference
Sharpe ratio: Return per unit of total volatility	1.96	1.87	+0.10
Sortino ratio: Return per unit of downside risk	2.81	2.60	+0.21
Omega ratio: Gain probability vs. loss probability	1.34	1.32	+0.02
Calmar ratio: Return relative to maximum drawdown	3.31	3.12	+0.18
Martin ratio: Return relative to average drawdown	13.10	11.05	+2.05
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

FLAPX vs. FSMAX - Sharpe Ratio Comparison

The current FLAPX Sharpe Ratio is 1.96, which is comparable to the FSMAX Sharpe Ratio of 1.87. The chart below compares the historical Sharpe Ratios of FLAPX and FSMAX, 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

	FLAPX	FSMAX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	1.96	1.87	+0.10
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.52	0.31	+0.21
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	—	0.40	—
Sharpe Ratio (All Time) Calculated using the full available price history	0.61	0.46	+0.15

Drawdowns

FLAPX vs. FSMAX - Drawdown Comparison

The maximum FLAPX drawdown since its inception was -40.31%, smaller than the maximum FSMAX drawdown of -50.55%. Use the drawdown chart below to compare losses from any high point for FLAPX and FSMAX.

Drawdown Indicators

	FLAPX	FSMAX	Difference
Max Drawdown Largest peak-to-trough decline	-40.31%	-50.55%	+10.24%
Max Drawdown (1Y) Largest decline over 1 year	-9.21%	-10.26%	+1.05%
Max Drawdown (3Y) Largest decline over 3 years	-21.02%	-26.82%	+5.80%
Max Drawdown (5Y) Largest decline over 5 years	-26.09%	-36.31%	+10.22%
Max Drawdown (10Y) Largest decline over 10 years	—	-50.55%	—
Current Drawdown Current decline from peak	0.00%	0.00%	0.00%
Average Drawdown Average peak-to-trough decline	-6.12%	-12.17%	+6.05%
Ulcer Index Depth and duration of drawdowns from previous peaks	2.32%	2.90%	-0.58%

Volatility

FLAPX vs. FSMAX - Volatility Comparison

The current volatility for Fidelity Flex Mid Cap Index Fund (FLAPX) is 3.80%, while Fidelity Extended Market Index Fund (FSMAX) has a volatility of 4.70%. This indicates that FLAPX experiences smaller price fluctuations and is considered to be less risky than FSMAX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	FLAPX	FSMAX	Difference
Volatility (1M) Calculated over the trailing 1-month period	3.80%	4.70%	-0.90%
Volatility (6M) Calculated over the trailing 6-month period	11.55%	12.46%	-0.91%
Volatility (1Y) Calculated over the trailing 1-year period	15.51%	17.17%	-1.66%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	18.58%	22.33%	-3.75%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	19.95%	30.24%	-10.29%

FLAPX vs. FSMAX - Expense Ratio Comparison

FLAPX has a 0.00% expense ratio, which is lower than FSMAX's 0.04% expense ratio. Despite the difference, both funds are considered low-cost compared to the broader market, where average expense ratios usually range from 0.3% to 0.9%.

Dividends

FLAPX vs. FSMAX - Dividend Comparison

FLAPX has not paid dividends to shareholders, while FSMAX's dividend yield for the trailing twelve months is around 0.50%.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
FLAPX Fidelity Flex Mid Cap Index Fund	0.00%	0.00%	1.08%	1.99%	1.82%	2.83%	2.16%	2.18%	2.24%	0.44%	0.00%	0.00%
FSMAX Fidelity Extended Market Index Fund	0.50%	0.57%	0.48%	1.17%	1.90%	7.49%	2.14%	4.30%	6.09%	5.44%	4.85%	6.34%

Frequently Asked Questions

Can I hold both FLAPX and FSMAX in my portfolio?

With a correlation of 0.95, FLAPX and FSMAX 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, FLAPX or FSMAX?

FSMAX has higher volatility (4.70%) compared to FLAPX (3.80%). In terms of maximum drawdown, FLAPX dropped -40.31% vs FSMAX's -50.55%.

Which has better risk-adjusted returns?

FLAPX currently has the higher Sharpe Ratio (1.96 vs 1.87), 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.