SSMKX vs. PRGFX

Last updated Jun 3, 2026

SSMKX (State Street Small/Mid Cap Equity Index Fund) and PRGFX (T. Rowe Price Growth Stock Fund) are both mutual funds - SSMKX is a Mid Cap Blend Equities fund managed by State Street, while PRGFX is a Large Cap Growth Equities fund managed by T. Rowe Price. Over the past 10 years, SSMKX returned 12.36%/yr vs 16.12%/yr for PRGFX. A 0.78 correlation means they provide meaningful diversification when combined. SSMKX charges 0.04%/yr vs 0.63%/yr for PRGFX.

Performance

SSMKX vs. PRGFX - 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 T. Rowe Price Growth Stock Fund (PRGFX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, SSMKX achieves a 13.04% return, which is significantly higher than PRGFX's 7.45% return. Over the past 10 years, SSMKX has underperformed PRGFX with an annualized return of 12.36%, while PRGFX has yielded a comparatively higher 16.12% annualized return.

SSMKX

• 1D: 0.16%
• 1M: 4.26%
• YTD: 13.04%
• 6M: 13.30%
• 1Y: 30.31%
• 3Y*: 19.97%
• 5Y*: 7.00%
• 10Y*: 12.36%

PRGFX

• 1D: 0.64%
• 1M: 6.98%
• YTD: 7.45%
• 6M: 6.26%
• 1Y: 24.18%
• 3Y*: 25.03%
• 5Y*: 10.64%
• 10Y*: 16.12%

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

SSMKX vs. PRGFX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
SSMKX State Street Small/Mid Cap Equity Index Fund	13.04%	12.77%	17.20%	25.20%	-25.49%	12.38%	32.41%	27.82%	-9.02%	18.16%
PRGFX T. Rowe Price Growth Stock Fund	7.45%	15.64%	38.36%	45.33%	-40.12%	19.86%	36.92%	30.83%	-1.04%	33.57%

Correlation

The correlation between SSMKX and PRGFX is 0.65, which is moderate. They share some common price drivers but move independently often enough to provide real diversification benefit when combined.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	0.65
Correlation (3Y) Calculated over the trailing 3-year period	0.65
Correlation (5Y) Calculated over the trailing 5-year period	0.77
Correlation (10Y) Calculated over the trailing 10-year period	0.78
Correlation (All Time) Calculated using the full available price history since Jan 5, 2016	0.78

The correlation between SSMKX and PRGFX shifts across timeframes, from 0.65 (3 years) to 0.78 (all time), reflecting how their relationship changes across market environments.

Return for Risk

SSMKX vs. PRGFX — Risk / Return Rank

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

SSMKX

SSMKX Risk / Return Rank: 45
SSMKX Sharpe Ratio Rank: 38
SSMKX Sortino Ratio Rank: 37
SSMKX Omega Ratio Rank: 34
SSMKX Calmar Ratio Rank: 62
SSMKX Martin Ratio Rank: 54

PRGFX

PRGFX Risk / Return Rank: 22
PRGFX Sharpe Ratio Rank: 29
PRGFX Sortino Ratio Rank: 26
PRGFX Omega Ratio Rank: 27
PRGFX Calmar Ratio Rank: 14
PRGFX Martin Ratio Rank: 15

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. PRGFX - 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 T. Rowe Price Growth Stock Fund (PRGFX). 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	PRGFX	Difference
Sharpe ratio Return per unit of total volatility	1.82	1.59	+0.23
Sortino ratio Return per unit of downside risk	2.56	2.18	+0.38
Omega ratio Gain probability vs. loss probability	1.31	1.28	+0.04
Calmar ratio Return relative to maximum drawdown	3.03	1.39	+1.64
Martin ratio Return relative to average drawdown	11.02	4.44	+6.58
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. PRGFX - Sharpe Ratio Comparison

The current SSMKX Sharpe Ratio is 1.82, which is comparable to the PRGFX Sharpe Ratio of 1.59. The chart below compares the historical Sharpe Ratios of SSMKX and PRGFX, 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	PRGFX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	1.82	1.59	+0.23
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.32	0.46	-0.15
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.56	0.73	-0.17
Sharpe Ratio (All Time) Calculated using the full available price history	0.56	0.56	0.00

Drawdowns

SSMKX vs. PRGFX - Drawdown Comparison

The maximum SSMKX drawdown since its inception was -41.65%, smaller than the maximum PRGFX drawdown of -54.01%. Use the drawdown chart below to compare losses from any high point for SSMKX and PRGFX.

Drawdown Indicators

	SSMKX	PRGFX	Difference
Max Drawdown Largest peak-to-trough decline	-41.65%	-54.01%	+12.36%
Max Drawdown (1Y) Largest decline over 1 year	-10.03%	-18.02%	+7.99%
Max Drawdown (3Y) Largest decline over 3 years	-26.31%	-22.69%	-3.62%
Max Drawdown (5Y) Largest decline over 5 years	-35.19%	-46.44%	+11.25%
Max Drawdown (10Y) Largest decline over 10 years	-41.65%	-46.44%	+4.79%
Current Drawdown Current decline from peak	0.00%	0.00%	0.00%
Average Drawdown Average peak-to-trough decline	-8.70%	-10.67%	+1.97%
Ulcer Index Depth and duration of drawdowns from previous peaks	2.76%	5.63%	-2.87%

Volatility

SSMKX vs. PRGFX - Volatility Comparison

State Street Small/Mid Cap Equity Index Fund (SSMKX) has a higher volatility of 4.63% compared to T. Rowe Price Growth Stock Fund (PRGFX) at 3.52%. This indicates that SSMKX's price experiences larger fluctuations and is considered to be riskier than PRGFX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	SSMKX	PRGFX	Difference
Volatility (1M) Calculated over the trailing 1-month period	4.63%	3.52%	+1.11%
Volatility (6M) Calculated over the trailing 6-month period	12.33%	11.90%	+0.43%
Volatility (1Y) Calculated over the trailing 1-year period	16.91%	15.85%	+1.06%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	22.25%	23.10%	-0.85%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	22.26%	22.10%	+0.16%

SSMKX vs. PRGFX - Expense Ratio Comparison

SSMKX has a 0.05% expense ratio, which is lower than PRGFX's 0.63% expense ratio.

Dividends

SSMKX vs. PRGFX - Dividend Comparison

SSMKX's dividend yield for the trailing twelve months is around 4.51%, less than PRGFX's 12.64% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
PRGFX T. Rowe Price Growth Stock Fund	12.64%	13.58%	13.26%	3.34%	3.55%	9.34%	3.51%	1.81%	9.09%	13.57%	2.22%	7.23%
SSMKX State Street Small/Mid Cap Equity Index Fund	4.51%	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 PRGFX in my portfolio?

SSMKX and PRGFX have a correlation of 0.65, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, SSMKX or PRGFX?

SSMKX has higher volatility (4.63%) compared to PRGFX (3.52%). In terms of maximum drawdown, SSMKX dropped -41.65% vs PRGFX's -54.01%.

Which has better risk-adjusted returns?

SSMKX currently has the higher Sharpe Ratio (1.82 vs 1.59), 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.