NSIDX vs. MOPIX

Last updated Jun 4, 2026

NSIDX (Northern Small Cap Index Fund) and MOPIX (MainStay WMC Small Companies Fund) are both Small Cap Blend Equities funds. Over the past 10 years, NSIDX returned 10.98%/yr vs 9.35%/yr for MOPIX. Their correlation of 0.95 suggests significant overlap in exposure. NSIDX charges 0.10%/yr vs 0.97%/yr for MOPIX.

Performance

NSIDX vs. MOPIX - Performance Comparison

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

Returns By Period

In the year-to-date period, NSIDX achieves a 18.68% return, which is significantly lower than MOPIX's 27.70% return. Over the past 10 years, NSIDX has outperformed MOPIX with an annualized return of 10.98%, while MOPIX has yielded a comparatively lower 9.35% annualized return.

NSIDX

• 1D: 0.93%
• 1M: 4.97%
• YTD: 18.68%
• 6M: 17.43%
• 1Y: 41.27%
• 3Y*: 18.61%
• 5Y*: 6.47%
• 10Y*: 10.98%

MOPIX

• 1D: 0.76%
• 1M: 9.92%
• YTD: 27.70%
• 6M: 27.77%
• 1Y: 56.29%
• 3Y*: 23.19%
• 5Y*: 9.07%
• 10Y*: 9.35%

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

NSIDX vs. MOPIX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
NSIDX Northern Small Cap Index Fund	18.68%	12.88%	11.45%	16.87%	-20.63%	14.38%	19.59%	25.22%	-11.33%	14.62%
MOPIX MainStay WMC Small Companies Fund	27.70%	12.69%	16.07%	10.97%	-19.00%	17.55%	10.04%	17.70%	-16.42%	15.68%

Correlation

The correlation between NSIDX and MOPIX is 0.83, 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	0.83
Correlation (3Y) Calculated over the trailing 3-year period	0.91
Correlation (5Y) Calculated over the trailing 5-year period	0.93
Correlation (10Y) Calculated over the trailing 10-year period	0.95
Correlation (All Time) Calculated using the full available price history since Sep 7, 1999	0.95

The correlation between NSIDX and MOPIX shifts across timeframes, from 0.83 (1 year) to 0.95 (10 years), reflecting how their relationship changes across market environments.

Return for Risk

NSIDX vs. MOPIX — Risk / Return Rank

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

NSIDX

NSIDX Risk / Return Rank: 65
NSIDX Sharpe Ratio Rank: 58
NSIDX Sortino Ratio Rank: 56
NSIDX Omega Ratio Rank: 49
NSIDX Calmar Ratio Rank: 85
NSIDX Martin Ratio Rank: 75

MOPIX

MOPIX Risk / Return Rank: 91
MOPIX Sharpe Ratio Rank: 93
MOPIX Sortino Ratio Rank: 89
MOPIX Omega Ratio Rank: 80
MOPIX Calmar Ratio Rank: 96
MOPIX Martin Ratio Rank: 95

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.

NSIDX vs. MOPIX - Risk-Adjusted Trends Comparison

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

	NSIDX	MOPIX	Difference
Sharpe ratio Return per unit of total volatility	2.25	3.20	-0.95
Sortino ratio Return per unit of downside risk	3.15	4.37	-1.22
Omega ratio Gain probability vs. loss probability	1.38	1.53	-0.15
Calmar ratio Return relative to maximum drawdown	4.05	6.08	-2.03
Martin ratio Return relative to average drawdown	14.27	22.94	-8.67
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

NSIDX vs. MOPIX - Sharpe Ratio Comparison

The current NSIDX Sharpe Ratio is 2.25, which is comparable to the MOPIX Sharpe Ratio of 3.20. The chart below compares the historical Sharpe Ratios of NSIDX and MOPIX, 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

	NSIDX	MOPIX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	2.25	3.20	-0.95
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.27	0.40	-0.13
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.45	0.40	+0.05
Sharpe Ratio (All Time) Calculated using the full available price history	0.34	0.49	-0.15

Drawdowns

NSIDX vs. MOPIX - Drawdown Comparison

The maximum NSIDX drawdown since its inception was -59.02%, smaller than the maximum MOPIX drawdown of -68.08%. Use the drawdown chart below to compare losses from any high point for NSIDX and MOPIX.

Drawdown Indicators

	NSIDX	MOPIX	Difference
Max Drawdown Largest peak-to-trough decline	-59.02%	-68.08%	+9.06%
Max Drawdown (1Y) Largest decline over 1 year	-10.97%	-9.84%	-1.13%
Max Drawdown (3Y) Largest decline over 3 years	-27.71%	-26.99%	-0.72%
Max Drawdown (5Y) Largest decline over 5 years	-32.89%	-32.60%	-0.29%
Max Drawdown (10Y) Largest decline over 10 years	-42.09%	-48.01%	+5.92%
Current Drawdown Current decline from peak	-0.11%	0.00%	-0.11%
Average Drawdown Average peak-to-trough decline	-12.06%	-9.11%	-2.95%
Ulcer Index Depth and duration of drawdowns from previous peaks	3.09%	2.60%	+0.49%

Volatility

NSIDX vs. MOPIX - Volatility Comparison

The current volatility for Northern Small Cap Index Fund (NSIDX) is 5.61%, while MainStay WMC Small Companies Fund (MOPIX) has a volatility of 5.92%. This indicates that NSIDX experiences smaller price fluctuations and is considered to be less risky than MOPIX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	NSIDX	MOPIX	Difference
Volatility (1M) Calculated over the trailing 1-month period	5.61%	5.92%	-0.31%
Volatility (6M) Calculated over the trailing 6-month period	13.67%	13.71%	-0.04%
Volatility (1Y) Calculated over the trailing 1-year period	19.77%	18.68%	+1.09%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	24.23%	22.81%	+1.42%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	24.26%	23.38%	+0.88%

NSIDX vs. MOPIX - Expense Ratio Comparison

NSIDX has a 0.10% expense ratio, which is lower than MOPIX's 0.97% expense ratio.

Dividends

NSIDX vs. MOPIX - Dividend Comparison

NSIDX's dividend yield for the trailing twelve months is around 1.33%, more than MOPIX's 0.12% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
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%
NSIDX Northern Small Cap Index Fund	1.33%	1.57%	6.72%	2.01%	6.38%	12.15%	3.52%	1.78%	12.16%	6.55%	4.06%	6.68%

Frequently Asked Questions

Can I hold both NSIDX and MOPIX in my portfolio?

NSIDX and MOPIX have a correlation of 0.83, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, NSIDX or MOPIX?

MOPIX has higher volatility (5.92%) compared to NSIDX (5.61%). In terms of maximum drawdown, NSIDX dropped -59.02% vs MOPIX's -68.08%.

Which has better risk-adjusted returns?

MOPIX currently has the higher Sharpe Ratio (3.20 vs 2.25), 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.