PARMX vs. NOSIX

Last updated Jun 10, 2026

PARMX (Parnassus Mid Cap Fund) and NOSIX (Northern Stock Index Fund) are both mutual funds - PARMX is a Mid Cap Blend Equities fund managed by Parnassus, while NOSIX is a Large Cap Blend Equities fund managed by Northern Funds. Over the past 10 years, PARMX returned 8.61%/yr vs 15.27%/yr for NOSIX. Their correlation of 0.89 suggests significant overlap in exposure. PARMX charges 0.96%/yr vs 0.05%/yr for NOSIX.

Performance

PARMX vs. NOSIX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Parnassus Mid Cap Fund (PARMX) and Northern Stock Index Fund (NOSIX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, PARMX achieves a 5.09% return, which is significantly lower than NOSIX's 8.73% return. Over the past 10 years, PARMX has underperformed NOSIX with an annualized return of 8.61%, while NOSIX has yielded a comparatively higher 15.27% annualized return.

PARMX

• 1D: 0.12%
• 1M: -0.47%
• YTD: 5.09%
• 6M: 5.69%
• 1Y: 14.65%
• 3Y*: 13.88%
• 5Y*: 4.51%
• 10Y*: 8.61%

NOSIX

• 1D: 0.30%
• 1M: 0.23%
• YTD: 8.73%
• 6M: 8.90%
• 1Y: 24.76%
• 3Y*: 21.44%
• 5Y*: 13.43%
• 10Y*: 15.27%

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

PARMX vs. NOSIX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
PARMX Parnassus Mid Cap Fund	5.09%	12.86%	10.05%	12.66%	-21.41%	16.38%	14.88%	28.74%	-6.67%	15.80%
NOSIX Northern Stock Index Fund	8.73%	17.83%	24.87%	26.24%	-18.25%	28.55%	18.33%	31.35%	-4.54%	21.71%

Correlation

The correlation between PARMX and NOSIX 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	0.73
Correlation (5Y) Calculated over the trailing 5-year period	0.82
Correlation (10Y) Calculated over the trailing 10-year period	0.85
Correlation (All Time) Calculated using the full available price history since Apr 29, 2005	0.89

Over the past year, the correlation between PARMX and NOSIX has dropped to 0.65 - well below their long-term average of 0.89, suggesting their price drivers have been diverging.

Return for Risk

PARMX vs. NOSIX — Risk / Return Rank

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

PARMX

PARMX Risk / Return Rank: 21
PARMX Sharpe Ratio Rank: 19
PARMX Sortino Ratio Rank: 20
PARMX Omega Ratio Rank: 17
PARMX Calmar Ratio Rank: 21
PARMX Martin Ratio Rank: 28

NOSIX

NOSIX Risk / Return Rank: 70
NOSIX Sharpe Ratio Rank: 68
NOSIX Sortino Ratio Rank: 64
NOSIX Omega Ratio Rank: 66
NOSIX Calmar Ratio Rank: 71
NOSIX Martin Ratio Rank: 81

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.

PARMX vs. NOSIX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Parnassus Mid Cap Fund (PARMX) and Northern Stock Index Fund (NOSIX). 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.

	PARMX	NOSIX	Difference
Sharpe ratio: Return per unit of total volatility	1.03	2.06	-1.04
Sortino ratio: Return per unit of downside risk	1.57	2.81	-1.24
Omega ratio: Gain probability vs. loss probability	1.18	1.38	-0.20
Calmar ratio: Return relative to maximum drawdown	1.45	2.84	-1.38
Martin ratio: Return relative to average drawdown	5.69	13.17	-7.48
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

PARMX vs. NOSIX - Sharpe Ratio Comparison

The current PARMX Sharpe Ratio is 1.03, which is lower than the NOSIX Sharpe Ratio of 2.06. The chart below compares the historical Sharpe Ratios of PARMX and NOSIX, 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

	PARMX	NOSIX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	1.03	2.06	-1.04
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.26	0.78	-0.53
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.49	0.84	-0.35
Sharpe Ratio (All Time) Calculated using the full available price history	0.47	0.50	-0.03

Drawdowns

PARMX vs. NOSIX - Drawdown Comparison

The maximum PARMX drawdown since its inception was -49.88%, smaller than the maximum NOSIX drawdown of -55.42%. Use the drawdown chart below to compare losses from any high point for PARMX and NOSIX.

Drawdown Indicators

	PARMX	NOSIX	Difference
Max Drawdown Largest peak-to-trough decline	-49.88%	-55.42%	+5.54%
Max Drawdown (1Y) Largest decline over 1 year	-10.49%	-8.89%	-1.60%
Max Drawdown (3Y) Largest decline over 3 years	-20.73%	-18.75%	-1.98%
Max Drawdown (5Y) Largest decline over 5 years	-29.27%	-24.54%	-4.73%
Max Drawdown (10Y) Largest decline over 10 years	-37.39%	-33.82%	-3.57%
Current Drawdown Current decline from peak	-1.83%	-2.64%	+0.81%
Average Drawdown Average peak-to-trough decline	-6.89%	-10.32%	+3.43%
Ulcer Index Depth and duration of drawdowns from previous peaks	2.66%	1.90%	+0.76%

Volatility

PARMX vs. NOSIX - Volatility Comparison

Parnassus Mid Cap Fund (PARMX) and Northern Stock Index Fund (NOSIX) have volatilities of 3.77% and 3.78%, 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

	PARMX	NOSIX	Difference
Volatility (1M) Calculated over the trailing 1-month period	3.77%	3.78%	-0.01%
Volatility (6M) Calculated over the trailing 6-month period	11.42%	9.40%	+2.02%
Volatility (1Y) Calculated over the trailing 1-year period	14.86%	12.25%	+2.61%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	17.56%	17.24%	+0.32%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	17.71%	18.23%	-0.52%

PARMX vs. NOSIX - Expense Ratio Comparison

PARMX has a 0.96% expense ratio, which is higher than NOSIX's 0.05% expense ratio.

Dividends

PARMX vs. NOSIX - Dividend Comparison

PARMX's dividend yield for the trailing twelve months is around 9.75%, more than NOSIX's 2.71% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
NOSIX Northern Stock Index Fund	2.71%	2.94%	2.59%	5.02%	4.72%	3.22%	4.00%	2.41%	4.82%	3.13%	2.76%	3.36%
PARMX Parnassus Mid Cap Fund	9.75%	10.25%	9.92%	2.29%	4.90%	4.88%	0.36%	4.15%	3.90%	4.19%	2.76%	6.42%

Frequently Asked Questions

Can I hold both PARMX and NOSIX in my portfolio?

PARMX and NOSIX 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, PARMX or NOSIX?

NOSIX has higher volatility (3.78%) compared to PARMX (3.77%). In terms of maximum drawdown, PARMX dropped -49.88% vs NOSIX's -55.42%.

Which has better risk-adjusted returns?

NOSIX currently has the higher Sharpe Ratio (2.06 vs 1.03), 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.