MDIDX vs. FSOSX

Last updated Jun 24, 2026

MDIDX (MFS International Diversification Fund Class A) and FSOSX (Fidelity Series Overseas Fund) are both Foreign Large Cap Equities funds. Over the past 5 years, MDIDX returned 7.10%/yr vs 7.40%/yr for FSOSX. Their correlation of 0.93 suggests significant overlap in exposure. MDIDX charges 1.08%/yr vs 0.01%/yr for FSOSX.

Performance

MDIDX vs. FSOSX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in MFS International Diversification Fund Class A (MDIDX) and Fidelity Series Overseas Fund (FSOSX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

The year-to-date returns for both stocks are quite close, with MDIDX having a 9.89% return and FSOSX slightly lower at 9.78%.

MDIDX

• 1D: -0.13%
• 1M: 1.83%
• YTD: 9.89%
• 6M: 9.65%
• 1Y: 22.73%
• 3Y*: 16.00%
• 5Y*: 7.10%
• 10Y*: 10.14%

FSOSX

• 1D: 0.61%
• 1M: 5.33%
• YTD: 9.78%
• 6M: 9.27%
• 1Y: 14.49%
• 3Y*: 14.96%
• 5Y*: 7.40%
• 10Y*: —

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

MDIDX vs. FSOSX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019
MDIDX MFS International Diversification Fund Class A	9.89%	27.58%	6.12%	14.05%	-17.31%	7.42%	14.99%	8.33%
FSOSX Fidelity Series Overseas Fund	9.78%	21.29%	5.87%	21.49%	-23.25%	19.59%	16.36%	7.78%

Correlation

The correlation between MDIDX and FSOSX is 0.88, 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	0.88
Correlation (3Y) Calculated over the trailing 3-year period	0.90
Correlation (5Y) Calculated over the trailing 5-year period	0.92
Correlation (All Time) Calculated using the full available price history since Jun 28, 2019	0.93

The correlation between MDIDX and FSOSX has been stable across timeframes, ranging from 0.88 to 0.93 - a consistent structural relationship.

Return for Risk

MDIDX vs. FSOSX — Risk / Return Rank

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

MDIDX

MDIDX Risk / Return Rank: 39
MDIDX Sharpe Ratio Rank: 42
MDIDX Sortino Ratio Rank: 40
MDIDX Omega Ratio Rank: 43
MDIDX Calmar Ratio Rank: 33
MDIDX Martin Ratio Rank: 36

FSOSX

FSOSX Risk / Return Rank: 14
FSOSX Sharpe Ratio Rank: 12
FSOSX Sortino Ratio Rank: 13
FSOSX Omega Ratio Rank: 12
FSOSX Calmar Ratio Rank: 15
FSOSX Martin Ratio Rank: 18

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.

MDIDX vs. FSOSX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for MFS International Diversification Fund Class A (MDIDX) and Fidelity Series Overseas Fund (FSOSX). 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.

	MDIDX	FSOSX	Difference
Sharpe ratio: Return per unit of total volatility	1.76	0.88	+0.87
Sortino ratio: Return per unit of downside risk	2.45	1.35	+1.10
Omega ratio: Gain probability vs. loss probability	1.33	1.17	+0.16
Calmar ratio: Return relative to maximum drawdown	2.01	1.25	+0.76
Martin ratio: Return relative to average drawdown	7.56	4.43	+3.12

MDIDX vs. FSOSX - Sharpe Ratio Comparison

The current MDIDX Sharpe Ratio is 1.76, which is higher than the FSOSX Sharpe Ratio of 0.88. The chart below compares the historical Sharpe Ratios of MDIDX and FSOSX, 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

MDIDX vs. FSOSX - Drawdown Comparison

The maximum MDIDX drawdown since its inception was -56.80%, which is greater than FSOSX's maximum drawdown of -35.36%. Use the drawdown chart below to compare losses from any high point for MDIDX and FSOSX.

Drawdown Indicators

	MDIDX	FSOSX	Difference
Max Drawdown Largest peak-to-trough decline	-56.80%	-35.36%	-21.44%
Max Drawdown (1Y) Largest decline over 1 year	-11.41%	-12.39%	+0.98%
Max Drawdown (3Y) Largest decline over 3 years	-12.60%	-14.07%	+1.47%
Max Drawdown (5Y) Largest decline over 5 years	-30.40%	-35.36%	+4.96%
Max Drawdown (10Y) Largest decline over 10 years	-30.40%	—	—
Current Drawdown Current decline from peak	-0.23%	0.00%	-0.23%
Average Drawdown Average peak-to-trough decline	-9.33%	-7.74%	-1.59%
Ulcer Index Depth and duration of drawdowns from previous peaks	3.03%	3.49%	-0.46%

Volatility

MDIDX vs. FSOSX - Volatility Comparison

The current volatility for MFS International Diversification Fund Class A (MDIDX) is 4.87%, while Fidelity Series Overseas Fund (FSOSX) has a volatility of 6.30%. This indicates that MDIDX experiences smaller price fluctuations and is considered to be less risky than FSOSX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	MDIDX	FSOSX	Difference
Volatility (1M) Calculated over the trailing 1-month period	4.87%	6.30%	-1.43%
Volatility (6M) Calculated over the trailing 6-month period	11.00%	15.32%	-4.32%
Volatility (1Y) Calculated over the trailing 1-year period	13.11%	17.64%	-4.53%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	14.35%	17.85%	-3.50%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	14.71%	19.10%	-4.39%

MDIDX vs. FSOSX - Expense Ratio Comparison

MDIDX has a 1.08% expense ratio, which is higher than FSOSX's 0.01% expense ratio.

Dividends

MDIDX vs. FSOSX - Dividend Comparison

MDIDX's dividend yield for the trailing twelve months is around 4.54%, less than FSOSX's 8.33% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
FSOSX Fidelity Series Overseas Fund	8.33%	9.15%	2.25%	1.63%	1.80%	2.92%	1.12%	0.37%	0.00%	0.00%	0.00%	0.00%
MDIDX MFS International Diversification Fund Class A	4.54%	4.99%	3.27%	3.94%	2.41%	2.47%	1.45%	2.30%	2.89%	1.42%	1.94%	1.60%

Frequently Asked Questions

Can I hold both MDIDX and FSOSX in my portfolio?

MDIDX and FSOSX have a correlation of 0.88, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, MDIDX or FSOSX?

FSOSX has higher volatility (6.30%) compared to MDIDX (4.87%). In terms of maximum drawdown, MDIDX dropped -56.80% vs FSOSX's -35.36%.

Which has better risk-adjusted returns?

MDIDX currently has the higher Sharpe Ratio (1.76 vs 0.88), 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.