FSSNX vs. FLXSX

Last updated Jun 24, 2026

FSSNX (Fidelity Small Cap Index Fund) and FLXSX (Fidelity Flex Small Cap Index Fund) are both Small Cap Blend Equities funds from Fidelity. Over the past 5 years, FSSNX returned 7.03%/yr vs 6.52%/yr for FLXSX. With a 1.00 correlation, they move nearly in lockstep. FSSNX charges 0.03%/yr vs 0.00%/yr for FLXSX.

Performance

FSSNX vs. FLXSX - Performance Comparison

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

Returns By Period

In the year-to-date period, FSSNX achieves a 21.76% return, which is significantly higher than FLXSX's 19.89% return.

FSSNX

• 1D: 0.83%
• 1M: 4.84%
• YTD: 21.76%
• 6M: 18.99%
• 1Y: 42.83%
• 3Y*: 19.92%
• 5Y*: 7.03%
• 10Y*: 11.85%

FLXSX

• 1D: 0.23%
• 1M: 4.48%
• YTD: 19.89%
• 6M: 16.95%
• 1Y: 39.44%
• 3Y*: 18.97%
• 5Y*: 6.52%
• 10Y*: —

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

FSSNX vs. FLXSX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
FSSNX Fidelity Small Cap Index Fund	21.76%	12.94%	11.71%	17.11%	-20.28%	14.70%	19.99%	25.70%	-11.24%	13.55%
FLXSX Fidelity Flex Small Cap Index Fund	19.89%	12.02%	11.67%	17.11%	-20.29%	14.84%	20.06%	25.69%	-11.13%	14.28%

Correlation

The correlation between FSSNX and FLXSX is 0.99 - 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	0.99
Correlation (3Y) Calculated over the trailing 3-year period	0.99
Correlation (5Y) Calculated over the trailing 5-year period	1.00
Correlation (All Time) Calculated using the full available price history since Mar 9, 2017	1.00

The correlation between FSSNX and FLXSX has been stable across timeframes, ranging from 0.99 to 1.00 - a consistent structural relationship.

Return for Risk

FSSNX vs. FLXSX — Risk / Return Rank

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

FSSNX

FSSNX Risk / Return Rank: 72
FSSNX Sharpe Ratio Rank: 72
FSSNX Sortino Ratio Rank: 65
FSSNX Omega Ratio Rank: 53
FSSNX Calmar Ratio Rank: 88
FSSNX Martin Ratio Rank: 83

FLXSX

FLXSX Risk / Return Rank: 59
FLXSX Sharpe Ratio Rank: 57
FLXSX Sortino Ratio Rank: 53
FLXSX Omega Ratio Rank: 44
FLXSX Calmar Ratio Rank: 79
FLXSX Martin Ratio Rank: 64

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.

FSSNX vs. FLXSX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Fidelity Small Cap Index Fund (FSSNX) and Fidelity Flex Small Cap Index Fund (FLXSX). 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.

	FSSNX	FLXSX	Difference
Sharpe ratio: Return per unit of total volatility	2.26	2.06	+0.20
Sortino ratio: Return per unit of downside risk	3.08	2.82	+0.26
Omega ratio: Gain probability vs. loss probability	1.37	1.33	+0.04
Calmar ratio: Return relative to maximum drawdown	4.05	3.38	+0.68
Martin ratio: Return relative to average drawdown	14.35	11.83	+2.52

FSSNX vs. FLXSX - Sharpe Ratio Comparison

The current FSSNX Sharpe Ratio is 2.26, which is comparable to the FLXSX Sharpe Ratio of 2.06. The chart below compares the historical Sharpe Ratios of FSSNX and FLXSX, 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

FSSNX vs. FLXSX - Drawdown Comparison

The maximum FSSNX drawdown since its inception was -41.72%, roughly equal to the maximum FLXSX drawdown of -41.72%. Use the drawdown chart below to compare losses from any high point for FSSNX and FLXSX.

Drawdown Indicators

	FSSNX	FLXSX	Difference
Max Drawdown Largest peak-to-trough decline	-41.72%	-41.72%	0.00%
Max Drawdown (1Y) Largest decline over 1 year	-11.00%	-12.25%	+1.25%
Max Drawdown (3Y) Largest decline over 3 years	-27.45%	-27.48%	+0.03%
Max Drawdown (5Y) Largest decline over 5 years	-31.87%	-31.88%	+0.01%
Max Drawdown (10Y) Largest decline over 10 years	-41.72%	—	—
Current Drawdown Current decline from peak	0.00%	0.00%	0.00%
Average Drawdown Average peak-to-trough decline	-8.27%	-10.39%	+2.12%
Ulcer Index Depth and duration of drawdowns from previous peaks	3.10%	3.48%	-0.38%

Volatility

FSSNX vs. FLXSX - Volatility Comparison

Fidelity Small Cap Index Fund (FSSNX) has a higher volatility of 6.43% compared to Fidelity Flex Small Cap Index Fund (FLXSX) at 5.69%. This indicates that FSSNX's price experiences larger fluctuations and is considered to be riskier than FLXSX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	FSSNX	FLXSX	Difference
Volatility (1M) Calculated over the trailing 1-month period	6.43%	5.69%	+0.74%
Volatility (6M) Calculated over the trailing 6-month period	14.33%	14.63%	-0.30%
Volatility (1Y) Calculated over the trailing 1-year period	19.75%	20.15%	-0.40%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	22.67%	22.72%	-0.05%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	23.50%	23.99%	-0.49%

FSSNX vs. FLXSX - Expense Ratio Comparison

FSSNX has a 0.03% expense ratio, which is higher than FLXSX's 0.00% 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

FSSNX vs. FLXSX - Dividend Comparison

FSSNX's dividend yield for the trailing twelve months is around 0.89%, while FLXSX has not paid dividends to shareholders.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
FLXSX Fidelity Flex Small Cap Index Fund	0.00%	0.00%	1.36%	1.49%	1.26%	2.74%	1.06%	2.86%	2.31%	0.77%	0.00%	0.00%
FSSNX Fidelity Small Cap Index Fund	0.89%	1.08%	1.04%	1.43%	1.26%	3.92%	0.94%	2.96%	4.94%	3.37%	2.27%	2.66%

Frequently Asked Questions

Can I hold both FSSNX and FLXSX in my portfolio?

With a correlation of 0.99, FSSNX and FLXSX 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, FSSNX or FLXSX?

FSSNX has higher volatility (6.43%) compared to FLXSX (5.69%). In terms of maximum drawdown, FSSNX dropped -41.72% vs FLXSX's -41.72%.

Which has better risk-adjusted returns?

FSSNX currently has the higher Sharpe Ratio (2.26 vs 2.06), 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.