SSFDX vs. FMDGX

Last updated Jun 23, 2026

SSFDX (State Street Aggregate Bond Index Fund) and FMDGX (Fidelity Mid Cap Growth Index Fund) are both mutual funds - SSFDX is a Intermediate Core Bond fund managed by State Street, while FMDGX is a Mid Cap Growth Equities fund tracking the Russell Midcap Growth Index. Over the past 5 years, SSFDX returned -0.14%/yr vs 6.11%/yr for FMDGX. At a 0.12 correlation, their price movements are largely independent. SSFDX charges 0.23%/yr vs 0.05%/yr for FMDGX.

Performance

SSFDX vs. FMDGX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in State Street Aggregate Bond Index Fund (SSFDX) and Fidelity Mid Cap Growth Index Fund (FMDGX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, SSFDX achieves a 0.62% return, which is significantly lower than FMDGX's 3.93% return.

SSFDX

• 1D: 0.27%
• 1M: 0.90%
• YTD: 0.62%
• 6M: 0.76%
• 1Y: 4.75%
• 3Y*: 3.90%
• 5Y*: -0.14%
• 10Y*: 1.45%

FMDGX

• 1D: 1.05%
• 1M: 1.93%
• YTD: 3.93%
• 6M: 1.36%
• 1Y: 6.22%
• 3Y*: 14.87%
• 5Y*: 6.11%
• 10Y*: —

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

SSFDX vs. FMDGX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019
SSFDX State Street Aggregate Bond Index Fund	0.62%	6.80%	1.36%	5.39%	-13.36%	-1.98%	7.57%	2.62%
FMDGX Fidelity Mid Cap Growth Index Fund	3.93%	8.60%	22.03%	25.79%	-26.67%	12.67%	34.84%	4.63%

Correlation

The correlation between SSFDX and FMDGX is 0.34, which is low. Their price movements are largely independent, making them effective diversification partners.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	0.34
Correlation (3Y) Calculated over the trailing 3-year period	0.23
Correlation (5Y) Calculated over the trailing 5-year period	0.17
Correlation (All Time) Calculated using the full available price history since Jul 17, 2019	0.12

Over the past year, SSFDX and FMDGX have become more correlated (0.34) than their long-term average of 0.12, meaning their price movements have been converging.

Return for Risk

SSFDX vs. FMDGX — Risk / Return Rank

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

SSFDX

SSFDX Risk / Return Rank: 24
SSFDX Sharpe Ratio Rank: 24
SSFDX Sortino Ratio Rank: 25
SSFDX Omega Ratio Rank: 23
SSFDX Calmar Ratio Rank: 25
SSFDX Martin Ratio Rank: 22

FMDGX

FMDGX Risk / Return Rank: 5
FMDGX Sharpe Ratio Rank: 5
FMDGX Sortino Ratio Rank: 5
FMDGX Omega Ratio Rank: 5
FMDGX Calmar Ratio Rank: 5
FMDGX Martin Ratio Rank: 5

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.

SSFDX vs. FMDGX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for State Street Aggregate Bond Index Fund (SSFDX) and Fidelity Mid Cap Growth Index Fund (FMDGX). 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.

	SSFDX	FMDGX	Difference
Sharpe ratio: Return per unit of total volatility	1.31	0.35	+0.96
Sortino ratio: Return per unit of downside risk	1.96	0.61	+1.35
Omega ratio: Gain probability vs. loss probability	1.23	1.07	+0.16
Calmar ratio: Return relative to maximum drawdown	1.75	0.40	+1.35
Martin ratio: Return relative to average drawdown	5.03	1.16	+3.87

SSFDX vs. FMDGX - Sharpe Ratio Comparison

The current SSFDX Sharpe Ratio is 1.31, which is higher than the FMDGX Sharpe Ratio of 0.35. The chart below compares the historical Sharpe Ratios of SSFDX and FMDGX, 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

SSFDX vs. FMDGX - Drawdown Comparison

The maximum SSFDX drawdown since its inception was -26.93%, smaller than the maximum FMDGX drawdown of -38.59%. Use the drawdown chart below to compare losses from any high point for SSFDX and FMDGX.

Drawdown Indicators

	SSFDX	FMDGX	Difference
Max Drawdown Largest peak-to-trough decline	-26.93%	-38.59%	+11.66%
Max Drawdown (1Y) Largest decline over 1 year	-2.75%	-14.75%	+12.00%
Max Drawdown (3Y) Largest decline over 3 years	-6.13%	-25.30%	+19.17%
Max Drawdown (5Y) Largest decline over 5 years	-18.19%	-38.59%	+20.40%
Max Drawdown (10Y) Largest decline over 10 years	-26.93%	—	—
Current Drawdown Current decline from peak	-3.06%	-1.97%	-1.09%
Average Drawdown Average peak-to-trough decline	-4.66%	-11.14%	+6.48%
Ulcer Index Depth and duration of drawdowns from previous peaks	0.96%	5.09%	-4.13%

Volatility

SSFDX vs. FMDGX - Volatility Comparison

The current volatility for State Street Aggregate Bond Index Fund (SSFDX) is 1.14%, while Fidelity Mid Cap Growth Index Fund (FMDGX) has a volatility of 5.90%. This indicates that SSFDX experiences smaller price fluctuations and is considered to be less risky than FMDGX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	SSFDX	FMDGX	Difference
Volatility (1M) Calculated over the trailing 1-month period	1.14%	5.90%	-4.76%
Volatility (6M) Calculated over the trailing 6-month period	2.72%	13.43%	-10.71%
Volatility (1Y) Calculated over the trailing 1-year period	3.67%	17.04%	-13.37%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	5.93%	22.45%	-16.52%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	14.11%	24.31%	-10.20%

SSFDX vs. FMDGX - Expense Ratio Comparison

SSFDX has a 0.23% expense ratio, which is higher than FMDGX's 0.05% 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

SSFDX vs. FMDGX - Dividend Comparison

SSFDX's dividend yield for the trailing twelve months is around 4.10%, more than FMDGX's 1.78% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
FMDGX Fidelity Mid Cap Growth Index Fund	1.78%	1.85%	0.47%	0.63%	0.81%	6.43%	0.36%	0.29%	0.00%	0.00%	0.00%	0.00%
SSFDX State Street Aggregate Bond Index Fund	4.10%	3.64%	3.59%	2.95%	2.27%	3.12%	3.00%	3.15%	2.79%	2.43%	2.19%	4.63%

Frequently Asked Questions

Can I hold both SSFDX and FMDGX in my portfolio?

SSFDX and FMDGX have a correlation of 0.34, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, SSFDX or FMDGX?

FMDGX has higher volatility (5.90%) compared to SSFDX (1.14%). In terms of maximum drawdown, SSFDX dropped -26.93% vs FMDGX's -38.59%.

Which has better risk-adjusted returns?

SSFDX currently has the higher Sharpe Ratio (1.31 vs 0.35), 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.