MRGCX vs. SSSYX

Last updated Jun 4, 2026

MRGCX (MFS Core Equity Fund Class C) and SSSYX (State Street Equity 500 Index Fund Class K) are both Large Cap Blend Equities funds. MRGCX is actively managed, while SSSYX is passively managed. Over the past 10 years, MRGCX returned 14.52%/yr vs 15.61%/yr for SSSYX. With a 0.97 correlation, they move nearly in lockstep. MRGCX charges 1.63%/yr vs 0.02%/yr for SSSYX.

Performance

MRGCX vs. SSSYX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in MFS Core Equity Fund Class C (MRGCX) and State Street Equity 500 Index Fund Class K (SSSYX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, MRGCX achieves a 7.80% return, which is significantly lower than SSSYX's 11.69% return. Over the past 10 years, MRGCX has underperformed SSSYX with an annualized return of 14.52%, while SSSYX has yielded a comparatively higher 15.61% annualized return.

MRGCX

• 1D: -0.19%
• 1M: 3.22%
• YTD: 7.80%
• 6M: 7.62%
• 1Y: 19.12%
• 3Y*: 20.57%
• 5Y*: 11.89%
• 10Y*: 14.52%

SSSYX

• 1D: 0.14%
• 1M: 5.79%
• YTD: 11.69%
• 6M: 11.73%
• 1Y: 28.94%
• 3Y*: 22.73%
• 5Y*: 14.24%
• 10Y*: 15.61%

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

MRGCX vs. SSSYX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
MRGCX MFS Core Equity Fund Class C	7.80%	11.47%	31.22%	21.54%	-17.85%	24.35%	17.64%	33.99%	-4.85%	23.51%
SSSYX State Street Equity 500 Index Fund Class K	11.69%	17.81%	24.99%	26.27%	-18.16%	28.51%	18.31%	31.38%	-4.38%	21.61%

Correlation

The correlation between MRGCX and SSSYX is 0.96 - 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	0.96
Correlation (3Y) Calculated over the trailing 3-year period	0.97
Correlation (5Y) Calculated over the trailing 5-year period	0.98
Correlation (10Y) Calculated over the trailing 10-year period	0.97
Correlation (All Time) Calculated using the full available price history since Sep 19, 2014	0.97

The correlation between MRGCX and SSSYX has been stable across timeframes, ranging from 0.96 to 0.98 - a consistent structural relationship.

Return for Risk

MRGCX vs. SSSYX — Risk / Return Rank

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

MRGCX

MRGCX Risk / Return Rank: 33
MRGCX Sharpe Ratio Rank: 33
MRGCX Sortino Ratio Rank: 31
MRGCX Omega Ratio Rank: 32
MRGCX Calmar Ratio Rank: 30
MRGCX Martin Ratio Rank: 39

SSSYX

SSSYX Risk / Return Rank: 73
SSSYX Sharpe Ratio Rank: 75
SSSYX Sortino Ratio Rank: 67
SSSYX Omega Ratio Rank: 67
SSSYX Calmar Ratio Rank: 74
SSSYX Martin Ratio Rank: 83

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.

MRGCX vs. SSSYX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for MFS Core Equity Fund Class C (MRGCX) and State Street Equity 500 Index Fund Class K (SSSYX). 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.

	MRGCX	SSSYX	Difference
Sharpe ratio: Return per unit of total volatility	1.66	2.52	-0.85
Sortino ratio: Return per unit of downside risk	2.33	3.42	-1.09
Omega ratio: Gain probability vs. loss probability	1.30	1.46	-0.16
Calmar ratio: Return relative to maximum drawdown	2.06	3.36	-1.30
Martin ratio: Return relative to average drawdown	8.64	15.69	-7.05
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

MRGCX vs. SSSYX - Sharpe Ratio Comparison

The current MRGCX Sharpe Ratio is 1.66, which is lower than the SSSYX Sharpe Ratio of 2.52. The chart below compares the historical Sharpe Ratios of MRGCX and SSSYX, 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

	MRGCX	SSSYX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	1.66	2.52	-0.85
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.69	0.85	-0.16
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.81	0.13	+0.68
Sharpe Ratio (All Time) Calculated using the full available price history	0.48	0.12	+0.36

Drawdowns

MRGCX vs. SSSYX - Drawdown Comparison

The maximum MRGCX drawdown since its inception was -54.44%, smaller than the maximum SSSYX drawdown of -91.48%. Use the drawdown chart below to compare losses from any high point for MRGCX and SSSYX.

Drawdown Indicators

	MRGCX	SSSYX	Difference
Max Drawdown Largest peak-to-trough decline	-54.44%	-91.48%	+37.04%
Max Drawdown (1Y) Largest decline over 1 year	-9.64%	-8.88%	-0.76%
Max Drawdown (3Y) Largest decline over 3 years	-19.35%	-18.74%	-0.61%
Max Drawdown (5Y) Largest decline over 5 years	-23.55%	-24.49%	+0.94%
Max Drawdown (10Y) Largest decline over 10 years	-33.47%	-91.48%	+58.01%
Current Drawdown Current decline from peak	-0.19%	0.00%	-0.19%
Average Drawdown Average peak-to-trough decline	-9.06%	-4.15%	-4.91%
Ulcer Index Depth and duration of drawdowns from previous peaks	2.29%	1.90%	+0.39%

Volatility

MRGCX vs. SSSYX - Volatility Comparison

The current volatility for MFS Core Equity Fund Class C (MRGCX) is 2.58%, while State Street Equity 500 Index Fund Class K (SSSYX) has a volatility of 2.82%. This indicates that MRGCX experiences smaller price fluctuations and is considered to be less risky than SSSYX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	MRGCX	SSSYX	Difference
Volatility (1M) Calculated over the trailing 1-month period	2.58%	2.82%	-0.24%
Volatility (6M) Calculated over the trailing 6-month period	9.15%	8.96%	+0.19%
Volatility (1Y) Calculated over the trailing 1-year period	11.94%	11.85%	+0.09%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	17.29%	16.88%	+0.41%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	18.03%	124.46%	-106.43%

MRGCX vs. SSSYX - Expense Ratio Comparison

MRGCX has a 1.63% expense ratio, which is higher than SSSYX's 0.02% expense ratio.

Dividends

MRGCX vs. SSSYX - Dividend Comparison

MRGCX's dividend yield for the trailing twelve months is around 15.71%, more than SSSYX's 1.29% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
MRGCX MFS Core Equity Fund Class C	15.71%	16.94%	19.09%	2.31%	4.16%	8.53%	1.36%	3.45%	12.15%	7.14%	3.44%	11.73%
SSSYX State Street Equity 500 Index Fund Class K	1.29%	1.44%	1.63%	1.78%	2.16%	2.76%	1.86%	4.44%	5.18%	5.94%	2.07%	1.84%

Frequently Asked Questions

Can I hold both MRGCX and SSSYX in my portfolio?

With a correlation of 0.96, MRGCX and SSSYX 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, MRGCX or SSSYX?

SSSYX has higher volatility (2.82%) compared to MRGCX (2.58%). In terms of maximum drawdown, MRGCX dropped -54.44% vs SSSYX's -91.48%.

Which has better risk-adjusted returns?

SSSYX currently has the higher Sharpe Ratio (2.52 vs 1.66), 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.