THDIX vs. FERGX

Last updated Jun 4, 2026

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

Performance

THDIX vs. FERGX - Performance Comparison

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

Returns By Period

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

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%

FERGX

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

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

THDIX vs. FERGX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
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%
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%

Correlation

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

Return for Risk

THDIX vs. FERGX — Risk / Return Rank

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

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

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

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.

THDIX vs. FERGX - Risk-Adjusted Trends Comparison

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

	THDIX	FERGX	Difference
Sharpe ratio: Return per unit of total volatility	3.10	3.32	-0.22
Sortino ratio: Return per unit of downside risk	4.10	4.20	-0.09
Omega ratio: Gain probability vs. loss probability	1.54	1.62	-0.08
Calmar ratio: Return relative to maximum drawdown	4.35	4.46	-0.11
Martin ratio: Return relative to average drawdown	16.72	17.57	-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.

THDIX vs. FERGX - Sharpe Ratio Comparison

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

	THDIX	FERGX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	3.10	3.32	-0.22
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.29	0.46	-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	0.46	0.57	-0.10

Drawdowns

THDIX vs. FERGX - Drawdown Comparison

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

Drawdown Indicators

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

Volatility

THDIX vs. FERGX - Volatility Comparison

The current volatility for Thornburg Developing World Fund (THDIX) is 5.79%, while Fidelity SAI Emerging Markets Index Fund (FERGX) has a volatility of 7.58%. This indicates that THDIX experiences smaller price fluctuations and is considered to be less risky than FERGX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

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

THDIX vs. FERGX - Expense Ratio Comparison

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

Dividends

THDIX vs. FERGX - Dividend Comparison

THDIX's dividend yield for the trailing twelve months is around 2.76%, more than FERGX's 2.06% 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 THDIX and FERGX in my portfolio?

THDIX and FERGX 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, THDIX or FERGX?

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

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.