MDIJX vs. MAILX

Last updated Jun 23, 2026

MDIJX (MFS International Diversification Fund) and MAILX (BlackRock International Fund of BlackRock Series, Inc.) are both Foreign Large Cap Equities funds. Over the past 10 years, MDIJX returned 9.98%/yr vs 8.23%/yr for MAILX. Their correlation of 0.92 suggests significant overlap in exposure. MDIJX charges 0.82%/yr vs 0.65%/yr for MAILX.

Performance

MDIJX vs. MAILX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in MFS International Diversification Fund (MDIJX) and BlackRock International Fund of BlackRock Series, Inc. (MAILX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, MDIJX achieves a 10.19% return, which is significantly lower than MAILX's 12.68% return. Over the past 10 years, MDIJX has outperformed MAILX with an annualized return of 9.98%, while MAILX has yielded a comparatively lower 8.23% annualized return.

MDIJX

• 1D: 0.63%
• 1M: 2.00%
• YTD: 10.19%
• 6M: 10.53%
• 1Y: 23.33%
• 3Y*: 15.14%
• 5Y*: 7.56%
• 10Y*: 9.98%

MAILX

• 1D: 1.42%
• 1M: 3.31%
• YTD: 12.68%
• 6M: 13.65%
• 1Y: 24.52%
• 3Y*: 11.10%
• 5Y*: 2.68%
• 10Y*: 8.23%

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

MDIJX vs. MAILX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
MDIJX MFS International Diversification Fund	10.19%	27.84%	6.41%	14.37%	-17.12%	7.69%	15.26%	26.00%	-11.05%	30.29%
MAILX BlackRock International Fund of BlackRock Series, Inc.	12.68%	15.60%	0.46%	19.67%	-24.24%	9.32%	21.82%	31.77%	-21.45%	31.87%

Correlation

The correlation between MDIJX and MAILX is 0.87, 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	0.87
Correlation (3Y) Calculated over the trailing 3-year period	0.87
Correlation (5Y) Calculated over the trailing 5-year period	0.91
Correlation (10Y) Calculated over the trailing 10-year period	0.89
Correlation (All Time) Calculated using the full available price history since Sep 30, 2004	0.92

The correlation between MDIJX and MAILX has been stable across timeframes, ranging from 0.87 to 0.92 - a consistent structural relationship.

Return for Risk

MDIJX vs. MAILX — Risk / Return Rank

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

MDIJX

MDIJX Risk / Return Rank: 38
MDIJX Sharpe Ratio Rank: 41
MDIJX Sortino Ratio Rank: 39
MDIJX Omega Ratio Rank: 41
MDIJX Calmar Ratio Rank: 31
MDIJX Martin Ratio Rank: 36

MAILX

MAILX Risk / Return Rank: 31
MAILX Sharpe Ratio Rank: 31
MAILX Sortino Ratio Rank: 29
MAILX Omega Ratio Rank: 31
MAILX Calmar Ratio Rank: 30
MAILX Martin Ratio Rank: 34

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.

MDIJX vs. MAILX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for MFS International Diversification Fund (MDIJX) and BlackRock International Fund of BlackRock Series, Inc. (MAILX). 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.

	MDIJX	MAILX	Difference
Sharpe ratio: Return per unit of total volatility	1.73	1.50	+0.23
Sortino ratio: Return per unit of downside risk	2.42	2.11	+0.30
Omega ratio: Gain probability vs. loss probability	1.32	1.27	+0.05
Calmar ratio: Return relative to maximum drawdown	1.99	1.92	+0.06
Martin ratio: Return relative to average drawdown	7.46	7.16	+0.30

MDIJX vs. MAILX - Sharpe Ratio Comparison

The current MDIJX Sharpe Ratio is 1.73, which is comparable to the MAILX Sharpe Ratio of 1.50. The chart below compares the historical Sharpe Ratios of MDIJX and MAILX, 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

MDIJX vs. MAILX - Drawdown Comparison

The maximum MDIJX drawdown since its inception was -56.60%, roughly equal to the maximum MAILX drawdown of -59.57%. Use the drawdown chart below to compare losses from any high point for MDIJX and MAILX.

Drawdown Indicators

	MDIJX	MAILX	Difference
Max Drawdown Largest peak-to-trough decline	-56.60%	-59.57%	+2.97%
Max Drawdown (1Y) Largest decline over 1 year	-11.40%	-12.34%	+0.94%
Max Drawdown (3Y) Largest decline over 3 years	-12.57%	-17.36%	+4.79%
Max Drawdown (5Y) Largest decline over 5 years	-30.19%	-41.68%	+11.49%
Max Drawdown (10Y) Largest decline over 10 years	-30.19%	-41.68%	+11.49%
Current Drawdown Current decline from peak	-0.07%	-0.08%	+0.01%
Average Drawdown Average peak-to-trough decline	-9.08%	-16.11%	+7.03%
Ulcer Index Depth and duration of drawdowns from previous peaks	3.03%	3.30%	-0.27%

Volatility

MDIJX vs. MAILX - Volatility Comparison

The current volatility for MFS International Diversification Fund (MDIJX) is 4.94%, while BlackRock International Fund of BlackRock Series, Inc. (MAILX) has a volatility of 6.29%. This indicates that MDIJX experiences smaller price fluctuations and is considered to be less risky than MAILX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	MDIJX	MAILX	Difference
Volatility (1M) Calculated over the trailing 1-month period	4.94%	6.29%	-1.35%
Volatility (6M) Calculated over the trailing 6-month period	11.03%	13.59%	-2.56%
Volatility (1Y) Calculated over the trailing 1-year period	13.11%	15.83%	-2.72%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	14.34%	18.02%	-3.68%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	14.73%	18.40%	-3.67%

MDIJX vs. MAILX - Expense Ratio Comparison

MDIJX has a 0.82% expense ratio, which is higher than MAILX's 0.65% expense ratio.

Dividends

MDIJX vs. MAILX - Dividend Comparison

MDIJX's dividend yield for the trailing twelve months is around 4.69%, more than MAILX's 1.59% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
MAILX BlackRock International Fund of BlackRock Series, Inc.	1.59%	1.79%	0.90%	1.08%	1.13%	7.30%	0.33%	1.11%	1.83%	1.39%	1.62%	0.65%
MDIJX MFS International Diversification Fund	4.69%	5.17%	3.50%	4.14%	2.64%	2.70%	1.64%	2.50%	3.14%	1.63%	2.18%	1.69%

Frequently Asked Questions

Can I hold both MDIJX and MAILX in my portfolio?

MDIJX and MAILX have a correlation of 0.87, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, MDIJX or MAILX?

MAILX has higher volatility (6.29%) compared to MDIJX (4.94%). In terms of maximum drawdown, MDIJX dropped -56.60% vs MAILX's -59.57%.

Which has better risk-adjusted returns?

MDIJX currently has the higher Sharpe Ratio (1.73 vs 1.50), 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.