BTMKX vs. FSOSX

Last updated Jun 3, 2026

BTMKX (iShares MSCI EAFE International Index Fund) and FSOSX (Fidelity Series Overseas Fund) are both Foreign Large Cap Equities funds. Over the past 5 years, BTMKX returned 8.76%/yr vs 6.40%/yr for FSOSX. Their correlation of 0.94 suggests significant overlap in exposure. BTMKX charges 0.05%/yr vs 0.01%/yr for FSOSX.

Performance

BTMKX vs. FSOSX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in iShares MSCI EAFE International Index Fund (BTMKX) and Fidelity Series Overseas Fund (FSOSX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, BTMKX achieves a 9.29% return, which is significantly higher than FSOSX's 4.62% return.

BTMKX

• 1D: -0.28%
• 1M: 2.62%
• YTD: 9.29%
• 6M: 12.25%
• 1Y: 21.09%
• 3Y*: 17.08%
• 5Y*: 8.76%
• 10Y*: 9.38%

FSOSX

• 1D: -0.64%
• 1M: 1.36%
• YTD: 4.62%
• 6M: 7.06%
• 1Y: 7.33%
• 3Y*: 12.80%
• 5Y*: 6.40%
• 10Y*: —

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

BTMKX vs. FSOSX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019
BTMKX iShares MSCI EAFE International Index Fund	9.29%	31.70%	3.70%	18.37%	-14.04%	11.30%	8.07%	6.80%
FSOSX Fidelity Series Overseas Fund	4.62%	21.29%	5.87%	21.49%	-23.25%	19.59%	16.36%	7.78%

Correlation

The correlation between BTMKX and FSOSX is 0.95 - these two move nearly in lockstep. At this level, holding both provides almost no diversification benefit. If you already own one, adding the other does little to reduce portfolio risk.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	0.95
Correlation (3Y) Calculated over the trailing 3-year period	0.94
Correlation (5Y) Calculated over the trailing 5-year period	0.95
Correlation (All Time) Calculated using the full available price history since Jul 1, 2019	0.95

The correlation between BTMKX and FSOSX has been stable across timeframes, ranging from 0.94 to 0.95 - a consistent structural relationship.

Return for Risk

BTMKX vs. FSOSX — Risk / Return Rank

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

BTMKX

BTMKX Risk / Return Rank: 27
BTMKX Sharpe Ratio Rank: 26
BTMKX Sortino Ratio Rank: 25
BTMKX Omega Ratio Rank: 26
BTMKX Calmar Ratio Rank: 27
BTMKX Martin Ratio Rank: 32

FSOSX

FSOSX Risk / Return Rank: 6
FSOSX Sharpe Ratio Rank: 6
FSOSX Sortino Ratio Rank: 6
FSOSX Omega Ratio Rank: 6
FSOSX Calmar Ratio Rank: 6
FSOSX 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.

BTMKX vs. FSOSX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for iShares MSCI EAFE International Index Fund (BTMKX) 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.

	BTMKX	FSOSX	Difference
Sharpe ratio Return per unit of total volatility	1.49	0.49	+1.00
Sortino ratio Return per unit of downside risk	2.13	0.81	+1.32
Omega ratio Gain probability vs. loss probability	1.27	1.10	+0.17
Calmar ratio Return relative to maximum drawdown	2.01	0.66	+1.35
Martin ratio Return relative to average drawdown	7.54	2.37	+5.17
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

BTMKX vs. FSOSX - Sharpe Ratio Comparison

The current BTMKX Sharpe Ratio is 1.49, which is higher than the FSOSX Sharpe Ratio of 0.49. The chart below compares the historical Sharpe Ratios of BTMKX 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.

Sharpe Ratios by Period

	BTMKX	FSOSX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	1.49	0.49	+1.00
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.54	0.36	+0.18
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.56	—	—
Sharpe Ratio (All Time) Calculated using the full available price history	0.39	0.50	-0.11

Drawdowns

BTMKX vs. FSOSX - Drawdown Comparison

The maximum BTMKX drawdown since its inception was -33.92%, roughly equal to the maximum FSOSX drawdown of -35.36%. Use the drawdown chart below to compare losses from any high point for BTMKX and FSOSX.

Drawdown Indicators

	BTMKX	FSOSX	Difference
Max Drawdown Largest peak-to-trough decline	-33.92%	-35.36%	+1.44%
Max Drawdown (1Y) Largest decline over 1 year	-11.30%	-12.39%	+1.09%
Max Drawdown (3Y) Largest decline over 3 years	-13.66%	-14.07%	+0.41%
Max Drawdown (5Y) Largest decline over 5 years	-29.23%	-35.36%	+6.13%
Max Drawdown (10Y) Largest decline over 10 years	-33.92%	—	—
Current Drawdown Current decline from peak	-0.70%	-2.25%	+1.55%
Average Drawdown Average peak-to-trough decline	-7.77%	-7.79%	+0.02%
Ulcer Index Depth and duration of drawdowns from previous peaks	3.01%	3.46%	-0.45%

Volatility

BTMKX vs. FSOSX - Volatility Comparison

The current volatility for iShares MSCI EAFE International Index Fund (BTMKX) is 4.73%, while Fidelity Series Overseas Fund (FSOSX) has a volatility of 6.13%. This indicates that BTMKX 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

	BTMKX	FSOSX	Difference
Volatility (1M) Calculated over the trailing 1-month period	4.73%	6.13%	-1.40%
Volatility (6M) Calculated over the trailing 6-month period	12.29%	14.28%	-1.99%
Volatility (1Y) Calculated over the trailing 1-year period	15.17%	16.81%	-1.64%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	16.17%	17.67%	-1.50%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	16.67%	19.05%	-2.38%

BTMKX vs. FSOSX - Expense Ratio Comparison

BTMKX has a 0.05% expense ratio, which is higher than FSOSX's 0.01% expense ratio. However, both funds are considered low-cost compared to the broader market, where average expense ratios usually range from 0.3% to 0.9%.

Dividends

BTMKX vs. FSOSX - Dividend Comparison

BTMKX's dividend yield for the trailing twelve months is around 3.43%, less than FSOSX's 8.75% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
BTMKX iShares MSCI EAFE International Index Fund	3.43%	3.74%	3.43%	3.19%	2.80%	3.06%	1.99%	3.34%	4.58%	2.45%	2.85%	2.42%
FSOSX Fidelity Series Overseas Fund	8.75%	9.15%	2.25%	1.63%	1.80%	2.92%	1.12%	0.37%	0.00%	0.00%	0.00%	0.00%

Frequently Asked Questions

Can I hold both BTMKX and FSOSX in my portfolio?

With a correlation of 0.95, BTMKX and FSOSX 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, BTMKX or FSOSX?

FSOSX has higher volatility (6.13%) compared to BTMKX (4.73%). In terms of maximum drawdown, BTMKX dropped -33.92% vs FSOSX's -35.36%.

Which has better risk-adjusted returns?

BTMKX currently has the higher Sharpe Ratio (1.49 vs 0.49), 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.