FERGX vs. THDIX

Last updated Jun 4, 2026

FERGX (Fidelity SAI Emerging Markets Index Fund) and THDIX (Thornburg Developing World Fund) are both Emerging Markets Diversified funds. Over the past 5 years, FERGX returned 7.84%/yr vs 4.79%/yr for THDIX. Their correlation of 0.84 suggests significant overlap in exposure. FERGX charges 0.07%/yr vs 1.06%/yr for THDIX.

Performance

FERGX vs. THDIX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Fidelity SAI Emerging Markets Index Fund (FERGX) and Thornburg Developing World Fund (THDIX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, FERGX achieves a 29.74% return, which is significantly higher than THDIX's 27.57% return.

FERGX

• 1D: 1.24%
• 1M: 10.65%
• YTD: 29.74%
• 6M: 32.65%
• 1Y: 58.65%
• 3Y*: 24.80%
• 5Y*: 7.84%
• 10Y*: —

THDIX

• 1D: 0.91%
• 1M: 8.91%
• YTD: 27.57%
• 6M: 31.97%
• 1Y: 50.49%
• 3Y*: 21.15%
• 5Y*: 4.79%
• 10Y*: 9.29%

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

FERGX vs. THDIX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
FERGX Fidelity SAI Emerging Markets Index Fund	29.74%	33.86%	6.59%	9.41%	-20.19%	-3.05%	17.46%	18.22%	-14.52%	33.62%
THDIX Thornburg Developing World Fund	27.57%	27.84%	5.80%	6.61%	-25.52%	-2.67%	22.98%	29.95%	-14.88%	35.44%

Correlation

The correlation between FERGX and THDIX is 0.64, which is moderate. They share some common price drivers but move independently often enough to provide real diversification benefit when combined.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	0.64
Correlation (3Y) Calculated over the trailing 3-year period	0.75
Correlation (5Y) Calculated over the trailing 5-year period	0.79
Correlation (All Time) Calculated using the full available price history since Jan 4, 2017	0.84

The correlation between FERGX and THDIX shifts across timeframes, from 0.64 (1 year) to 0.84 (all time), reflecting how their relationship changes across market environments.

Return for Risk

FERGX vs. THDIX — Risk / Return Rank

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

FERGX

FERGX Risk / Return Rank: 90
FERGX Sharpe Ratio Rank: 95
FERGX Sortino Ratio Rank: 88
FERGX Omega Ratio Rank: 89
FERGX Calmar Ratio Rank: 89
FERGX Martin Ratio Rank: 89

THDIX

THDIX Risk / Return Rank: 87
THDIX Sharpe Ratio Rank: 92
THDIX Sortino Ratio Rank: 86
THDIX Omega Ratio Rank: 82
THDIX Calmar Ratio Rank: 88
THDIX Martin Ratio Rank: 87

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.

FERGX vs. THDIX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Fidelity SAI Emerging Markets Index Fund (FERGX) and Thornburg Developing World Fund (THDIX). 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.

	FERGX	THDIX	Difference
Sharpe ratio: Return per unit of total volatility	3.32	3.10	+0.22
Sortino ratio: Return per unit of downside risk	4.20	4.10	+0.09
Omega ratio: Gain probability vs. loss probability	1.62	1.54	+0.08
Calmar ratio: Return relative to maximum drawdown	4.46	4.35	+0.11
Martin ratio: Return relative to average drawdown	17.57	16.72	+0.84
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

FERGX vs. THDIX - Sharpe Ratio Comparison

The current FERGX Sharpe Ratio is 3.32, which is comparable to the THDIX Sharpe Ratio of 3.10. The chart below compares the historical Sharpe Ratios of FERGX and THDIX, 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

	FERGX	THDIX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	3.32	3.10	+0.22
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.46	0.29	+0.17
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	—	0.54	—
Sharpe Ratio (All Time) Calculated using the full available price history	0.57	0.46	+0.10

Drawdowns

FERGX vs. THDIX - Drawdown Comparison

The maximum FERGX drawdown since its inception was -39.27%, smaller than the maximum THDIX drawdown of -44.31%. Use the drawdown chart below to compare losses from any high point for FERGX and THDIX.

Drawdown Indicators

	FERGX	THDIX	Difference
Max Drawdown Largest peak-to-trough decline	-39.27%	-44.31%	+5.04%
Max Drawdown (1Y) Largest decline over 1 year	-13.32%	-11.76%	-1.56%
Max Drawdown (3Y) Largest decline over 3 years	-16.20%	-16.09%	-0.11%
Max Drawdown (5Y) Largest decline over 5 years	-37.11%	-40.70%	+3.59%
Max Drawdown (10Y) Largest decline over 10 years	—	-44.31%	—
Current Drawdown Current decline from peak	0.00%	0.00%	0.00%
Average Drawdown Average peak-to-trough decline	-14.33%	-13.44%	-0.89%
Ulcer Index Depth and duration of drawdowns from previous peaks	3.36%	3.05%	+0.31%

Volatility

FERGX vs. THDIX - Volatility Comparison

Fidelity SAI Emerging Markets Index Fund (FERGX) has a higher volatility of 7.58% compared to Thornburg Developing World Fund (THDIX) at 5.79%. This indicates that FERGX's price experiences larger fluctuations and is considered to be riskier than THDIX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	FERGX	THDIX	Difference
Volatility (1M) Calculated over the trailing 1-month period	7.58%	5.79%	+1.79%
Volatility (6M) Calculated over the trailing 6-month period	15.44%	13.42%	+2.02%
Volatility (1Y) Calculated over the trailing 1-year period	17.88%	16.47%	+1.41%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	17.25%	16.64%	+0.61%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	17.99%	17.11%	+0.88%

FERGX vs. THDIX - Expense Ratio Comparison

FERGX has a 0.08% expense ratio, which is lower than THDIX's 1.06% expense ratio.

Dividends

FERGX vs. THDIX - Dividend Comparison

FERGX's dividend yield for the trailing twelve months is around 2.06%, less than THDIX's 2.76% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
FERGX Fidelity SAI Emerging Markets Index Fund	2.06%	2.67%	2.40%	2.67%	2.51%	2.90%	1.49%	2.49%	2.58%	0.58%	0.00%	0.00%
THDIX Thornburg Developing World Fund	2.76%	3.52%	2.90%	2.05%	1.77%	0.00%	0.15%	1.52%	1.31%	0.74%	0.55%	0.69%

Frequently Asked Questions

Can I hold both FERGX and THDIX in my portfolio?

FERGX and THDIX have a correlation of 0.64, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, FERGX or THDIX?

FERGX has higher volatility (7.58%) compared to THDIX (5.79%). In terms of maximum drawdown, FERGX dropped -39.27% vs THDIX's -44.31%.

Which has better risk-adjusted returns?

FERGX currently has the higher Sharpe Ratio (3.32 vs 3.10), 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.