SSMKX vs. FSMDX

Last updated Jun 4, 2026

SSMKX (State Street Small/Mid Cap Equity Index Fund) and FSMDX (Fidelity Mid Cap Index Fund) are both Mid Cap Blend Equities funds. Over the past 10 years, SSMKX returned 12.48%/yr vs 11.69%/yr for FSMDX. With a 0.96 correlation, they move nearly in lockstep. SSMKX charges 0.04%/yr vs 0.03%/yr for FSMDX.

Performance

SSMKX vs. FSMDX - Performance Comparison

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

Returns By Period

In the year-to-date period, SSMKX achieves a 14.17% return, which is significantly higher than FSMDX's 12.78% return. Over the past 10 years, SSMKX has outperformed FSMDX with an annualized return of 12.48%, while FSMDX has yielded a comparatively lower 11.69% annualized return.

SSMKX

• 1D: 1.00%
• 1M: 5.71%
• YTD: 14.17%
• 6M: 13.00%
• 1Y: 29.82%
• 3Y*: 20.36%
• 5Y*: 7.43%
• 10Y*: 12.48%

FSMDX

• 1D: 0.70%
• 1M: 4.12%
• YTD: 12.78%
• 6M: 12.57%
• 1Y: 22.14%
• 3Y*: 17.58%
• 5Y*: 8.41%
• 10Y*: 11.69%

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

SSMKX vs. FSMDX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
SSMKX State Street Small/Mid Cap Equity Index Fund	14.17%	12.77%	17.20%	25.20%	-25.49%	12.38%	32.41%	27.82%	-9.02%	18.16%
FSMDX Fidelity Mid Cap Index Fund	12.78%	10.58%	15.55%	17.20%	-17.27%	22.56%	17.13%	30.53%	-9.38%	18.04%

Correlation

The correlation between SSMKX and FSMDX is 0.95, 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	0.95
Correlation (3Y) Calculated over the trailing 3-year period	0.96
Correlation (5Y) Calculated over the trailing 5-year period	0.96
Correlation (10Y) Calculated over the trailing 10-year period	0.96
Correlation (All Time) Calculated using the full available price history since Jan 5, 2016	0.96

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

Return for Risk

SSMKX vs. FSMDX — Risk / Return Rank

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

SSMKX

SSMKX Risk / Return Rank: 48
SSMKX Sharpe Ratio Rank: 42
SSMKX Sortino Ratio Rank: 40
SSMKX Omega Ratio Rank: 37
SSMKX Calmar Ratio Rank: 67
SSMKX Martin Ratio Rank: 57

FSMDX

FSMDX Risk / Return Rank: 43
FSMDX Sharpe Ratio Rank: 37
FSMDX Sortino Ratio Rank: 36
FSMDX Omega Ratio Rank: 33
FSMDX Calmar Ratio Rank: 56
FSMDX Martin Ratio Rank: 55

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.

SSMKX vs. FSMDX - Risk-Adjusted Trends Comparison

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

	SSMKX	FSMDX	Difference
Sharpe ratio: Return per unit of total volatility	1.88	1.75	+0.13
Sortino ratio: Return per unit of downside risk	2.63	2.51	+0.12
Omega ratio: Gain probability vs. loss probability	1.32	1.30	+0.02
Calmar ratio: Return relative to maximum drawdown	3.16	2.87	+0.29
Martin ratio: Return relative to average drawdown	11.48	11.06	+0.42
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

SSMKX vs. FSMDX - Sharpe Ratio Comparison

The current SSMKX Sharpe Ratio is 1.88, which is comparable to the FSMDX Sharpe Ratio of 1.75. The chart below compares the historical Sharpe Ratios of SSMKX and FSMDX, 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

	SSMKX	FSMDX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	1.88	1.75	+0.13
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.34	0.46	-0.13
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.56	0.61	-0.04
Sharpe Ratio (All Time) Calculated using the full available price history	0.57	0.70	-0.13

Drawdowns

SSMKX vs. FSMDX - Drawdown Comparison

The maximum SSMKX drawdown since its inception was -41.65%, roughly equal to the maximum FSMDX drawdown of -40.35%. Use the drawdown chart below to compare losses from any high point for SSMKX and FSMDX.

Drawdown Indicators

	SSMKX	FSMDX	Difference
Max Drawdown Largest peak-to-trough decline	-41.65%	-40.35%	-1.30%
Max Drawdown (1Y) Largest decline over 1 year	-10.03%	-8.16%	-1.87%
Max Drawdown (3Y) Largest decline over 3 years	-26.31%	-20.92%	-5.39%
Max Drawdown (5Y) Largest decline over 5 years	-35.19%	-26.07%	-9.12%
Max Drawdown (10Y) Largest decline over 10 years	-41.65%	-40.35%	-1.30%
Current Drawdown Current decline from peak	0.00%	0.00%	0.00%
Average Drawdown Average peak-to-trough decline	-8.70%	-4.96%	-3.74%
Ulcer Index Depth and duration of drawdowns from previous peaks	2.76%	2.11%	+0.65%

Volatility

SSMKX vs. FSMDX - Volatility Comparison

State Street Small/Mid Cap Equity Index Fund (SSMKX) has a higher volatility of 4.70% compared to Fidelity Mid Cap Index Fund (FSMDX) at 3.31%. This indicates that SSMKX's price experiences larger fluctuations and is considered to be riskier than FSMDX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	SSMKX	FSMDX	Difference
Volatility (1M) Calculated over the trailing 1-month period	4.70%	3.31%	+1.39%
Volatility (6M) Calculated over the trailing 6-month period	12.35%	9.93%	+2.42%
Volatility (1Y) Calculated over the trailing 1-year period	16.90%	13.42%	+3.48%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	22.25%	18.26%	+3.99%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	22.26%	19.32%	+2.94%

SSMKX vs. FSMDX - Expense Ratio Comparison

SSMKX has a 0.05% expense ratio, which is higher than FSMDX's 0.03% 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

SSMKX vs. FSMDX - Dividend Comparison

SSMKX's dividend yield for the trailing twelve months is around 4.47%, more than FSMDX's 0.98% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
FSMDX Fidelity Mid Cap Index Fund	0.98%	1.10%	2.46%	1.39%	2.07%	3.35%	2.34%	2.86%	2.21%	2.17%	2.23%	2.84%
SSMKX State Street Small/Mid Cap Equity Index Fund	4.47%	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 SSMKX and FSMDX in my portfolio?

With a correlation of 0.95, SSMKX and FSMDX 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, SSMKX or FSMDX?

SSMKX has higher volatility (4.70%) compared to FSMDX (3.31%). In terms of maximum drawdown, SSMKX dropped -41.65% vs FSMDX's -40.35%.

Which has better risk-adjusted returns?

SSMKX currently has the higher Sharpe Ratio (1.88 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.