FSOPX vs. SSMKX

Last updated Jun 24, 2026

FSOPX (Fidelity Series Small Cap Opportunities Fund) and SSMKX (State Street Small/Mid Cap Equity Index Fund) are both mutual funds - FSOPX is a Small Cap Blend Equities fund managed by Fidelity, while SSMKX is a Mid Cap Blend Equities fund managed by State Street. Over the past 10 years, FSOPX returned 13.73%/yr vs 12.92%/yr for SSMKX. With a 0.95 correlation, they move nearly in lockstep. FSOPX charges 0.00%/yr vs 0.04%/yr for SSMKX.

Performance

FSOPX vs. SSMKX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Fidelity Series Small Cap Opportunities Fund (FSOPX) and State Street Small/Mid Cap Equity Index Fund (SSMKX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, FSOPX achieves a 22.32% return, which is significantly higher than SSMKX's 15.04% return. Over the past 10 years, FSOPX has outperformed SSMKX with an annualized return of 13.73%, while SSMKX has yielded a comparatively lower 12.92% annualized return.

FSOPX

• 1D: 1.28%
• 1M: 5.25%
• YTD: 22.32%
• 6M: 19.52%
• 1Y: 44.62%
• 3Y*: 22.77%
• 5Y*: 11.95%
• 10Y*: 13.73%

SSMKX

• 1D: 0.09%
• 1M: 4.28%
• YTD: 15.04%
• 6M: 12.75%
• 1Y: 29.43%
• 3Y*: 20.59%
• 5Y*: 7.00%
• 10Y*: 12.92%

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

FSOPX vs. SSMKX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
FSOPX Fidelity Series Small Cap Opportunities Fund	22.32%	15.81%	15.31%	20.38%	-17.82%	23.39%	17.03%	29.92%	-8.12%	11.10%
SSMKX State Street Small/Mid Cap Equity Index Fund	15.04%	12.77%	17.20%	25.20%	-25.49%	12.38%	32.41%	27.82%	-9.02%	18.16%

Correlation

The correlation between FSOPX and SSMKX is 0.91, 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	0.91
Correlation (3Y) Calculated over the trailing 3-year period	0.94
Correlation (5Y) Calculated over the trailing 5-year period	0.95
Correlation (10Y) Calculated over the trailing 10-year period	0.95
Correlation (All Time) Calculated using the full available price history since Jan 4, 2016	0.95

The correlation between FSOPX and SSMKX has been stable across timeframes, ranging from 0.91 to 0.95 - a consistent structural relationship.

Return for Risk

FSOPX vs. SSMKX — Risk / Return Rank

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

FSOPX

FSOPX Risk / Return Rank: 83
FSOPX Sharpe Ratio Rank: 83
FSOPX Sortino Ratio Rank: 80
FSOPX Omega Ratio Rank: 69
FSOPX Calmar Ratio Rank: 92
FSOPX Martin Ratio Rank: 93

SSMKX

SSMKX Risk / Return Rank: 49
SSMKX Sharpe Ratio Rank: 42
SSMKX Sortino Ratio Rank: 40
SSMKX Omega Ratio Rank: 37
SSMKX Calmar Ratio Rank: 69
SSMKX Martin Ratio Rank: 58

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.

FSOPX vs. SSMKX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Fidelity Series Small Cap Opportunities Fund (FSOPX) and State Street Small/Mid Cap Equity Index Fund (SSMKX). 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.

	FSOPX	SSMKX	Difference
Sharpe ratio: Return per unit of total volatility	2.51	1.75	+0.76
Sortino ratio: Return per unit of downside risk	3.49	2.46	+1.03
Omega ratio: Gain probability vs. loss probability	1.42	1.30	+0.12
Calmar ratio: Return relative to maximum drawdown	4.66	3.06	+1.60
Martin ratio: Return relative to average drawdown	18.08	11.03	+7.05

FSOPX vs. SSMKX - Sharpe Ratio Comparison

The current FSOPX Sharpe Ratio is 2.51, which is higher than the SSMKX Sharpe Ratio of 1.75. The chart below compares the historical Sharpe Ratios of FSOPX and SSMKX, 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

FSOPX vs. SSMKX - Drawdown Comparison

The maximum FSOPX drawdown since its inception was -61.75%, which is greater than SSMKX's maximum drawdown of -41.65%. Use the drawdown chart below to compare losses from any high point for FSOPX and SSMKX.

Drawdown Indicators

	FSOPX	SSMKX	Difference
Max Drawdown Largest peak-to-trough decline	-61.75%	-41.65%	-20.10%
Max Drawdown (1Y) Largest decline over 1 year	-9.99%	-10.03%	+0.04%
Max Drawdown (3Y) Largest decline over 3 years	-27.17%	-26.31%	-0.86%
Max Drawdown (5Y) Largest decline over 5 years	-30.06%	-35.19%	+5.13%
Max Drawdown (10Y) Largest decline over 10 years	-39.15%	-41.65%	+2.50%
Current Drawdown Current decline from peak	0.00%	-0.11%	+0.11%
Average Drawdown Average peak-to-trough decline	-10.35%	-8.66%	-1.69%
Ulcer Index Depth and duration of drawdowns from previous peaks	2.57%	2.78%	-0.21%

Volatility

FSOPX vs. SSMKX - Volatility Comparison

Fidelity Series Small Cap Opportunities Fund (FSOPX) and State Street Small/Mid Cap Equity Index Fund (SSMKX) have volatilities of 6.25% and 5.97%, respectively, indicating that both stocks experience similar levels of price fluctuations. This suggests that the risk associated with both stocks, as measured by volatility, is nearly the same. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	FSOPX	SSMKX	Difference
Volatility (1M) Calculated over the trailing 1-month period	6.25%	5.97%	+0.28%
Volatility (6M) Calculated over the trailing 6-month period	14.10%	13.15%	+0.95%
Volatility (1Y) Calculated over the trailing 1-year period	18.57%	17.55%	+1.02%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	21.78%	22.36%	-0.58%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	22.04%	22.31%	-0.27%

FSOPX vs. SSMKX - Expense Ratio Comparison

FSOPX has a 0.00% expense ratio, which is lower than SSMKX's 0.05% 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

FSOPX vs. SSMKX - Dividend Comparison

FSOPX's dividend yield for the trailing twelve months is around 3.61%, less than SSMKX's 4.43% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
FSOPX Fidelity Series Small Cap Opportunities Fund	3.61%	4.41%	9.41%	0.98%	5.16%	30.85%	2.01%	6.67%	13.99%	10.31%	0.69%	5.93%
SSMKX State Street Small/Mid Cap Equity Index Fund	4.43%	5.10%	2.12%	2.56%	17.09%	9.69%	1.47%	5.75%	3.68%	5.52%	1.30%	0.00%

Frequently Asked Questions

Can I hold both FSOPX and SSMKX in my portfolio?

With a correlation of 0.91, FSOPX and SSMKX 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, FSOPX or SSMKX?

FSOPX has higher volatility (6.25%) compared to SSMKX (5.97%). In terms of maximum drawdown, FSOPX dropped -61.75% vs SSMKX's -41.65%.

Which has better risk-adjusted returns?

FSOPX currently has the higher Sharpe Ratio (2.51 vs 1.75), 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.