MIDLX vs. WISIX

Last updated Apr 1, 2026

Compare and contrast key facts about MFS International New Discovery Fund Class R6 (MIDLX) and William Blair International Small Cap Growth Fund (WISIX).

MIDLX is a passively managed fund by MFS that tracks the performance of the MSCI All Country World ex-US Small Mid Cap Index. It was launched on Jun 1, 2012. WISIX is managed by William Blair. It was launched on Oct 31, 2005.

Performance

MIDLX vs. WISIX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in MFS International New Discovery Fund Class R6 (MIDLX) and William Blair International Small Cap Growth Fund (WISIX). The values are adjusted to include any dividend payments, if applicable.

MIDLX vs. WISIX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
MIDLX MFS International New Discovery Fund Class R6	-4.04%	17.03%	3.33%	13.21%	-18.52%	5.17%	10.15%	24.97%	-10.29%	30.65%
WISIX William Blair International Small Cap Growth Fund	-3.63%	15.31%	0.80%	14.72%	-34.99%	11.01%	29.09%	34.22%	-24.27%	32.71%

Returns By Period

In the year-to-date period, MIDLX achieves a -4.04% return, which is significantly lower than WISIX's -3.63% return. Over the past 10 years, MIDLX has outperformed WISIX with an annualized return of 6.07%, while WISIX has yielded a comparatively lower 4.74% annualized return.

MIDLX

• 1D: -0.25%
• 1M: -11.75%
• YTD: -4.04%
• 6M: -4.78%
• 1Y: 9.51%
• 3Y*: 7.41%
• 5Y*: 2.30%
• 10Y*: 6.07%

WISIX

• 1D: -1.60%
• 1M: -10.09%
• YTD: -3.63%
• 6M: -5.31%
• 1Y: 9.96%
• 3Y*: 6.21%
• 5Y*: -1.02%
• 10Y*: 4.74%

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

MIDLX vs. WISIX - Expense Ratio Comparison

MIDLX has a 0.91% expense ratio, which is lower than WISIX's 1.23% expense ratio.

WISIX

William Blair International Small Cap Growth Fund

MIDLX

MFS International New Discovery Fund Class R6

Return for Risk

MIDLX vs. WISIX — Risk / Return Rank

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

MIDLX

MIDLX Risk / Return Rank: 23
MIDLX Sharpe Ratio Rank: 27
MIDLX Sortino Ratio Rank: 22
MIDLX Omega Ratio Rank: 23
MIDLX Calmar Ratio Rank: 21
MIDLX Martin Ratio Rank: 22

WISIX

WISIX Risk / Return Rank: 20
WISIX Sharpe Ratio Rank: 21
WISIX Sortino Ratio Rank: 19
WISIX Omega Ratio Rank: 20
WISIX Calmar Ratio Rank: 22
WISIX Martin Ratio Rank: 19

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.

MIDLX vs. WISIX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for MFS International New Discovery Fund Class R6 (MIDLX) and William Blair International Small Cap Growth Fund (WISIX). 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.

	MIDLX	WISIX	Difference
Sharpe ratio Return per unit of total volatility	0.69	0.56	+0.13
Sortino ratio Return per unit of downside risk	0.95	0.83	+0.12
Omega ratio Gain probability vs. loss probability	1.14	1.12	+0.02
Calmar ratio Return relative to maximum drawdown	0.64	0.66	-0.02
Martin ratio Return relative to average drawdown	2.45	2.01	+0.45
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

MIDLX vs. WISIX - Sharpe Ratio Comparison

The current MIDLX Sharpe Ratio is 0.69, which is comparable to the WISIX Sharpe Ratio of 0.56. The chart below compares the historical Sharpe Ratios of MIDLX and WISIX, offering insights into how both investments have performed under varying market conditions. These values are calculated using daily returns over the previous 12 months.

Sharpe Ratios by Period

	MIDLX	WISIX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	0.69	0.56	+0.13
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.18	-0.06	+0.24
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.44	0.28	+0.16
Sharpe Ratio (All Time) Calculated using the full available price history	0.54	0.31	+0.23

Correlation

The correlation between MIDLX and WISIX is 0.85, which is considered to be high. That indicates a strong positive relationship between their price movements. Having highly-correlated positions in a portfolio may signal a lack of diversification, potentially leading to increased risk during market downturns.

Dividends

MIDLX vs. WISIX - Dividend Comparison

MIDLX's dividend yield for the trailing twelve months is around 3.51%, more than WISIX's 0.63% yield.

	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
MIDLX MFS International New Discovery Fund Class R6	3.51%	3.37%	10.08%	4.21%	5.85%	5.19%	4.03%	4.36%	6.82%	1.63%	1.09%	1.25%
WISIX William Blair International Small Cap Growth Fund	0.63%	0.61%	1.78%	0.88%	0.21%	16.20%	2.09%	0.31%	13.84%	9.94%	0.36%	2.31%

Drawdowns

MIDLX vs. WISIX - Drawdown Comparison

The maximum MIDLX drawdown since its inception was -34.70%, smaller than the maximum WISIX drawdown of -64.84%. Use the drawdown chart below to compare losses from any high point for MIDLX and WISIX.

Drawdown Indicators

	MIDLX	WISIX	Difference
Max Drawdown Largest peak-to-trough decline	-34.70%	-64.84%	+30.14%
Max Drawdown (1Y) Largest decline over 1 year	-11.75%	-10.09%	-1.66%
Max Drawdown (5Y) Largest decline over 5 years	-33.58%	-47.76%	+14.18%
Max Drawdown (10Y) Largest decline over 10 years	-34.70%	-47.76%	+13.06%
Current Drawdown Current decline from peak	-11.75%	-22.75%	+11.00%
Average Drawdown Average peak-to-trough decline	-6.96%	-16.60%	+9.64%
Ulcer Index Depth and duration of drawdowns from previous peaks	3.08%	3.67%	-0.59%

Volatility

MIDLX vs. WISIX - Volatility Comparison

The current volatility for MFS International New Discovery Fund Class R6 (MIDLX) is 5.06%, while William Blair International Small Cap Growth Fund (WISIX) has a volatility of 6.00%. This indicates that MIDLX experiences smaller price fluctuations and is considered to be less risky than WISIX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	MIDLX	WISIX	Difference
Volatility (1M) Calculated over the trailing 1-month period	5.06%	6.00%	-0.94%
Volatility (6M) Calculated over the trailing 6-month period	8.19%	9.88%	-1.69%
Volatility (1Y) Calculated over the trailing 1-year period	12.10%	15.08%	-2.98%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	13.05%	17.21%	-4.16%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	13.92%	17.23%	-3.31%