TLDIX vs. FZOLX

Last updated Jun 4, 2026

TLDIX (Thornburg Ultra Short Income Fund) and FZOLX (Fidelity SAI Low Duration Income Fund) are both Ultrashort Bond funds. Over the past 5 years, TLDIX returned 3.40%/yr vs 3.53%/yr for FZOLX. At a 0.41 correlation, their price movements are largely independent. TLDIX charges 0.76%/yr vs 0.22%/yr for FZOLX.

Performance

TLDIX vs. FZOLX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Thornburg Ultra Short Income Fund (TLDIX) and Fidelity SAI Low Duration Income Fund (FZOLX). 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 TLDIX having a 1.42% return and FZOLX slightly lower at 1.36%.

TLDIX

• 1D: 0.00%
• 1M: 0.28%
• YTD: 1.42%
• 6M: 1.80%
• 1Y: 4.19%
• 3Y*: 5.07%
• 5Y*: 3.40%
• 10Y*: 2.80%

FZOLX

• 1D: 0.00%
• 1M: 0.32%
• YTD: 1.36%
• 6M: 1.79%
• 1Y: 4.26%
• 3Y*: 5.14%
• 5Y*: 3.53%
• 10Y*: —

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

TLDIX vs. FZOLX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020
TLDIX Thornburg Ultra Short Income Fund	1.42%	4.84%	5.81%	4.92%	-0.00%	0.32%	0.52%
FZOLX Fidelity SAI Low Duration Income Fund	1.36%	4.85%	5.59%	5.72%	0.34%	-0.04%	0.11%

Correlation

The correlation between TLDIX and FZOLX is 0.33, which is low. Their price movements are largely independent, making them effective diversification partners.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	0.33
Correlation (3Y) Calculated over the trailing 3-year period	0.41
Correlation (5Y) Calculated over the trailing 5-year period	0.43
Correlation (All Time) Calculated using the full available price history since Sep 16, 2020	0.41

Return for Risk

TLDIX vs. FZOLX — Risk / Return Rank

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

TLDIX

TLDIX Risk / Return Rank: 99
TLDIX Sharpe Ratio Rank: 96
TLDIX Sortino Ratio Rank: 100
TLDIX Omega Ratio Rank: 100
TLDIX Calmar Ratio Rank: 99
TLDIX Martin Ratio Rank: 100

FZOLX

FZOLX Risk / Return Rank: 98
FZOLX Sharpe Ratio Rank: 95
FZOLX Sortino Ratio Rank: 99
FZOLX Omega Ratio Rank: 99
FZOLX Calmar Ratio Rank: 99
FZOLX Martin Ratio Rank: 100

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.

TLDIX vs. FZOLX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Thornburg Ultra Short Income Fund (TLDIX) and Fidelity SAI Low Duration Income Fund (FZOLX). 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.

	TLDIX	FZOLX	Difference
Sharpe ratio Return per unit of total volatility	3.55	3.36	+0.19
Sortino ratio Return per unit of downside risk	15.07	10.53	+4.54
Omega ratio Gain probability vs. loss probability	5.43	3.63	+1.80
Calmar ratio Return relative to maximum drawdown	17.12	14.30	+2.81
Martin ratio Return relative to average drawdown	83.37	74.84	+8.54
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

TLDIX vs. FZOLX - Sharpe Ratio Comparison

The current TLDIX Sharpe Ratio is 3.55, which is comparable to the FZOLX Sharpe Ratio of 3.36. The chart below compares the historical Sharpe Ratios of TLDIX and FZOLX, 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

	TLDIX	FZOLX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	3.55	3.36	+0.19
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	2.61	2.91	-0.30
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	2.23	—	—
Sharpe Ratio (All Time) Calculated using the full available price history	2.09	2.72	-0.63

Drawdowns

TLDIX vs. FZOLX - Drawdown Comparison

The maximum TLDIX drawdown since its inception was -3.43%, which is greater than FZOLX's maximum drawdown of -1.10%. Use the drawdown chart below to compare losses from any high point for TLDIX and FZOLX.

Drawdown Indicators

	TLDIX	FZOLX	Difference
Max Drawdown Largest peak-to-trough decline	-3.43%	-1.10%	-2.33%
Max Drawdown (1Y) Largest decline over 1 year	-0.25%	-0.30%	+0.05%
Max Drawdown (3Y) Largest decline over 3 years	-0.25%	-0.30%	+0.05%
Max Drawdown (5Y) Largest decline over 5 years	-1.39%	-1.10%	-0.29%
Max Drawdown (10Y) Largest decline over 10 years	-3.43%	—	—
Current Drawdown Current decline from peak	0.00%	0.00%	0.00%
Average Drawdown Average peak-to-trough decline	-0.16%	-0.13%	-0.03%
Ulcer Index Depth and duration of drawdowns from previous peaks	0.05%	0.06%	-0.01%

Volatility

TLDIX vs. FZOLX - Volatility Comparison

The current volatility for Thornburg Ultra Short Income Fund (TLDIX) is 0.14%, while Fidelity SAI Low Duration Income Fund (FZOLX) has a volatility of 0.38%. This indicates that TLDIX experiences smaller price fluctuations and is considered to be less risky than FZOLX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	TLDIX	FZOLX	Difference
Volatility (1M) Calculated over the trailing 1-month period	0.14%	0.38%	-0.24%
Volatility (6M) Calculated over the trailing 6-month period	0.62%	0.88%	-0.26%
Volatility (1Y) Calculated over the trailing 1-year period	1.19%	1.27%	-0.08%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	1.31%	1.22%	+0.09%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	1.26%	1.15%	+0.11%

TLDIX vs. FZOLX - Expense Ratio Comparison

TLDIX has a 0.76% expense ratio, which is higher than FZOLX's 0.22% expense ratio.

Dividends

TLDIX vs. FZOLX - Dividend Comparison

TLDIX's dividend yield for the trailing twelve months is around 4.44%, less than FZOLX's 5.09% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
FZOLX Fidelity SAI Low Duration Income Fund	5.09%	5.26%	5.15%	4.03%	1.14%	0.16%	0.01%	0.00%	0.00%	0.00%	0.00%	0.00%
TLDIX Thornburg Ultra Short Income Fund	4.44%	4.89%	5.64%	4.12%	2.12%	1.53%	2.32%	2.82%	2.37%	1.62%	1.24%	0.89%

Frequently Asked Questions

Can I hold both TLDIX and FZOLX in my portfolio?

TLDIX and FZOLX have a correlation of 0.33, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, TLDIX or FZOLX?

FZOLX has higher volatility (0.38%) compared to TLDIX (0.14%). In terms of maximum drawdown, TLDIX dropped -3.43% vs FZOLX's -1.10%.

Which has better risk-adjusted returns?

TLDIX currently has the higher Sharpe Ratio (3.55 vs 3.36), 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.