MOPIX vs. FSSNX

Last updated Jun 23, 2026

MOPIX (MainStay WMC Small Companies Fund) and FSSNX (Fidelity Small Cap Index Fund) are both Small Cap Blend Equities funds. Over the past 10 years, MOPIX returned 9.52%/yr vs 11.46%/yr for FSSNX. With a 0.96 correlation, they move nearly in lockstep. MOPIX charges 0.97%/yr vs 0.03%/yr for FSSNX.

Performance

MOPIX vs. FSSNX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in MainStay WMC Small Companies Fund (MOPIX) and Fidelity Small Cap Index Fund (FSSNX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, MOPIX achieves a 29.39% return, which is significantly higher than FSSNX's 20.76% return. Over the past 10 years, MOPIX has underperformed FSSNX with an annualized return of 9.52%, while FSSNX has yielded a comparatively higher 11.46% annualized return.

MOPIX

• 1D: 1.59%
• 1M: 4.37%
• YTD: 29.39%
• 6M: 26.00%
• 1Y: 58.23%
• 3Y*: 22.24%
• 5Y*: 10.04%
• 10Y*: 9.52%

FSSNX

• 1D: 2.10%
• 1M: 3.98%
• YTD: 20.76%
• 6M: 17.19%
• 1Y: 43.21%
• 3Y*: 18.44%
• 5Y*: 7.47%
• 10Y*: 11.46%

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

MOPIX vs. FSSNX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
MOPIX MainStay WMC Small Companies Fund	29.39%	12.69%	16.07%	10.97%	-19.00%	17.55%	10.04%	17.70%	-16.42%	15.68%
FSSNX Fidelity Small Cap Index Fund	20.76%	12.94%	11.71%	17.11%	-20.28%	14.70%	19.99%	25.70%	-11.24%	14.54%

Correlation

The correlation between MOPIX and FSSNX is 0.94, 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	0.94
Correlation (3Y) Calculated over the trailing 3-year period	0.95
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 Sep 9, 2011	0.96

The correlation between MOPIX and FSSNX has been stable across timeframes, ranging from 0.94 to 0.96 - a consistent structural relationship.

Return for Risk

MOPIX vs. FSSNX — Risk / Return Rank

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

MOPIX

MOPIX Risk / Return Rank: 92
MOPIX Sharpe Ratio Rank: 95
MOPIX Sortino Ratio Rank: 90
MOPIX Omega Ratio Rank: 82
MOPIX Calmar Ratio Rank: 96
MOPIX Martin Ratio Rank: 96

FSSNX

FSSNX Risk / Return Rank: 69
FSSNX Sharpe Ratio Rank: 66
FSSNX Sortino Ratio Rank: 62
FSSNX Omega Ratio Rank: 50
FSSNX Calmar Ratio Rank: 86
FSSNX Martin Ratio Rank: 80

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.

MOPIX vs. FSSNX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for MainStay WMC Small Companies Fund (MOPIX) and Fidelity Small Cap Index Fund (FSSNX). 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.

	MOPIX	FSSNX	Difference
Sharpe ratio: Return per unit of total volatility	3.03	2.19	+0.84
Sortino ratio: Return per unit of downside risk	4.12	2.99	+1.13
Omega ratio: Gain probability vs. loss probability	1.50	1.36	+0.15
Calmar ratio: Return relative to maximum drawdown	5.93	3.92	+2.01
Martin ratio: Return relative to average drawdown	22.27	13.88	+8.39

MOPIX vs. FSSNX - Sharpe Ratio Comparison

The current MOPIX Sharpe Ratio is 3.03, which is higher than the FSSNX Sharpe Ratio of 2.19. The chart below compares the historical Sharpe Ratios of MOPIX and FSSNX, 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

MOPIX vs. FSSNX - Drawdown Comparison

The maximum MOPIX drawdown since its inception was -68.08%, which is greater than FSSNX's maximum drawdown of -41.72%. Use the drawdown chart below to compare losses from any high point for MOPIX and FSSNX.

Drawdown Indicators

	MOPIX	FSSNX	Difference
Max Drawdown Largest peak-to-trough decline	-68.08%	-41.72%	-26.36%
Max Drawdown (1Y) Largest decline over 1 year	-9.84%	-11.00%	+1.16%
Max Drawdown (3Y) Largest decline over 3 years	-26.99%	-27.45%	+0.46%
Max Drawdown (5Y) Largest decline over 5 years	-32.60%	-31.87%	-0.73%
Max Drawdown (10Y) Largest decline over 10 years	-48.01%	-41.72%	-6.29%
Current Drawdown Current decline from peak	0.00%	0.00%	0.00%
Average Drawdown Average peak-to-trough decline	-9.10%	-8.27%	-0.83%
Ulcer Index Depth and duration of drawdowns from previous peaks	2.61%	3.10%	-0.49%

Volatility

MOPIX vs. FSSNX - Volatility Comparison

MainStay WMC Small Companies Fund (MOPIX) and Fidelity Small Cap Index Fund (FSSNX) have volatilities of 6.93% and 6.79%, 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

	MOPIX	FSSNX	Difference
Volatility (1M) Calculated over the trailing 1-month period	6.93%	6.79%	+0.14%
Volatility (6M) Calculated over the trailing 6-month period	14.60%	14.37%	+0.23%
Volatility (1Y) Calculated over the trailing 1-year period	19.21%	19.71%	-0.50%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	22.91%	22.68%	+0.23%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	23.43%	23.50%	-0.07%

MOPIX vs. FSSNX - Expense Ratio Comparison

MOPIX has a 0.97% expense ratio, which is higher than FSSNX's 0.03% expense ratio.

Dividends

MOPIX vs. FSSNX - Dividend Comparison

MOPIX's dividend yield for the trailing twelve months is around 0.12%, less than FSSNX's 0.90% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
FSSNX Fidelity Small Cap Index Fund	0.90%	1.08%	1.04%	1.43%	1.26%	3.92%	0.94%	2.96%	4.94%	3.37%	2.27%	2.66%
MOPIX MainStay WMC Small Companies Fund	0.12%	0.15%	0.39%	0.33%	2.34%	29.42%	0.00%	0.50%	18.09%	8.32%	0.59%	0.37%

Frequently Asked Questions

Can I hold both MOPIX and FSSNX in my portfolio?

With a correlation of 0.94, MOPIX and FSSNX 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, MOPIX or FSSNX?

MOPIX has higher volatility (6.93%) compared to FSSNX (6.79%). In terms of maximum drawdown, MOPIX dropped -68.08% vs FSSNX's -41.72%.

Which has better risk-adjusted returns?

MOPIX currently has the higher Sharpe Ratio (3.03 vs 2.19), 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.