MWNIX vs. COIIX

Last updated Jun 23, 2026

MWNIX (MFS International New Discovery Fund) and COIIX (Calvert International Opportunities Fund) are both Foreign Small & Mid Cap Equities funds. Over the past 10 years, MWNIX returned 6.48%/yr vs 6.68%/yr for COIIX. Their correlation of 0.91 suggests significant overlap in exposure. MWNIX charges 1.03%/yr vs 1.06%/yr for COIIX.

Performance

MWNIX vs. COIIX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in MFS International New Discovery Fund (MWNIX) and Calvert International Opportunities Fund (COIIX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, MWNIX achieves a 7.72% return, which is significantly higher than COIIX's 6.16% return. Both investments have delivered pretty close results over the past 10 years, with MWNIX having a 6.48% annualized return and COIIX not far ahead at 6.68%.

MWNIX

• 1D: 0.47%
• 1M: 1.48%
• YTD: 7.72%
• 6M: 7.82%
• 1Y: 12.59%
• 3Y*: 9.69%
• 5Y*: 3.31%
• 10Y*: 6.48%

COIIX

• 1D: 0.32%
• 1M: -0.42%
• YTD: 6.16%
• 6M: 6.16%
• 1Y: 9.01%
• 3Y*: 7.16%
• 5Y*: 0.96%
• 10Y*: 6.68%

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

MWNIX vs. COIIX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
MWNIX MFS International New Discovery Fund	7.72%	16.88%	0.90%	13.03%	-18.63%	5.06%	9.98%	22.85%	-10.41%	30.67%
COIIX Calvert International Opportunities Fund	6.16%	13.80%	-1.48%	12.95%	-26.69%	13.97%	14.05%	26.09%	-14.57%	38.55%

Correlation

The correlation between MWNIX and COIIX is 0.90, 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	0.90
Correlation (3Y) Calculated over the trailing 3-year period	0.92
Correlation (5Y) Calculated over the trailing 5-year period	0.93
Correlation (10Y) Calculated over the trailing 10-year period	0.92
Correlation (All Time) Calculated using the full available price history since May 31, 2007	0.91

The correlation between MWNIX and COIIX has been stable across timeframes, ranging from 0.90 to 0.93 - a consistent structural relationship.

Return for Risk

MWNIX vs. COIIX — Risk / Return Rank

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

MWNIX

MWNIX Risk / Return Rank: 13
MWNIX Sharpe Ratio Rank: 14
MWNIX Sortino Ratio Rank: 14
MWNIX Omega Ratio Rank: 14
MWNIX Calmar Ratio Rank: 11
MWNIX Martin Ratio Rank: 13

COIIX

COIIX Risk / Return Rank: 8
COIIX Sharpe Ratio Rank: 7
COIIX Sortino Ratio Rank: 8
COIIX Omega Ratio Rank: 8
COIIX Calmar Ratio Rank: 7
COIIX Martin Ratio Rank: 8

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.

MWNIX vs. COIIX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for MFS International New Discovery Fund (MWNIX) and Calvert International Opportunities Fund (COIIX). 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.

	MWNIX	COIIX	Difference
Sharpe ratio: Return per unit of total volatility	0.98	0.58	+0.40
Sortino ratio: Return per unit of downside risk	1.46	0.93	+0.53
Omega ratio: Gain probability vs. loss probability	1.19	1.11	+0.07
Calmar ratio: Return relative to maximum drawdown	0.99	0.63	+0.36
Martin ratio: Return relative to average drawdown	3.36	2.22	+1.14

MWNIX vs. COIIX - Sharpe Ratio Comparison

The current MWNIX Sharpe Ratio is 0.98, which is higher than the COIIX Sharpe Ratio of 0.58. The chart below compares the historical Sharpe Ratios of MWNIX and COIIX, 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

MWNIX vs. COIIX - Drawdown Comparison

The maximum MWNIX drawdown since its inception was -58.38%, roughly equal to the maximum COIIX drawdown of -57.27%. Use the drawdown chart below to compare losses from any high point for MWNIX and COIIX.

Drawdown Indicators

	MWNIX	COIIX	Difference
Max Drawdown Largest peak-to-trough decline	-58.38%	-57.27%	-1.11%
Max Drawdown (1Y) Largest decline over 1 year	-11.78%	-12.74%	+0.96%
Max Drawdown (3Y) Largest decline over 3 years	-15.12%	-17.12%	+2.00%
Max Drawdown (5Y) Largest decline over 5 years	-33.67%	-40.36%	+6.69%
Max Drawdown (10Y) Largest decline over 10 years	-34.72%	-40.36%	+5.64%
Current Drawdown Current decline from peak	-0.90%	-4.98%	+4.08%
Average Drawdown Average peak-to-trough decline	-9.56%	-14.95%	+5.39%
Ulcer Index Depth and duration of drawdowns from previous peaks	3.47%	3.64%	-0.17%

Volatility

MWNIX vs. COIIX - Volatility Comparison

MFS International New Discovery Fund (MWNIX) has a higher volatility of 4.15% compared to Calvert International Opportunities Fund (COIIX) at 3.77%. This indicates that MWNIX's price experiences larger fluctuations and is considered to be riskier than COIIX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	MWNIX	COIIX	Difference
Volatility (1M) Calculated over the trailing 1-month period	4.15%	3.77%	+0.38%
Volatility (6M) Calculated over the trailing 6-month period	10.06%	11.37%	-1.31%
Volatility (1Y) Calculated over the trailing 1-year period	11.93%	13.83%	-1.90%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	13.26%	16.99%	-3.73%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	13.99%	16.96%	-2.97%

MWNIX vs. COIIX - Expense Ratio Comparison

MWNIX has a 1.03% expense ratio, which is lower than COIIX's 1.06% expense ratio.

Dividends

MWNIX vs. COIIX - Dividend Comparison

MWNIX's dividend yield for the trailing twelve months is around 3.01%, less than COIIX's 3.29% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
COIIX Calvert International Opportunities Fund	3.29%	3.49%	3.24%	1.77%	0.61%	7.67%	0.78%	1.32%	9.82%	7.19%	1.52%	4.53%
MWNIX MFS International New Discovery Fund	3.01%	3.24%	7.61%	4.05%	5.68%	5.06%	3.90%	2.67%	6.68%	1.63%	1.09%	1.12%

Frequently Asked Questions

Can I hold both MWNIX and COIIX in my portfolio?

With a correlation of 0.90, MWNIX and COIIX 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, MWNIX or COIIX?

MWNIX has higher volatility (4.15%) compared to COIIX (3.77%). In terms of maximum drawdown, MWNIX dropped -58.38% vs COIIX's -57.27%.

Which has better risk-adjusted returns?

MWNIX currently has the higher Sharpe Ratio (0.98 vs 0.58), 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.