UGSDX vs. CULAX

Last updated Jun 4, 2026

UGSDX (U.S. Global Investors U.S. Government Ultra-Short Bond Fund) and CULAX (Calvert Ultra-Short Duration Income Fund) are both Ultrashort Bond funds. Over the past 10 years, UGSDX returned 1.57%/yr vs 2.47%/yr for CULAX. At a 0.07 correlation, their price movements are largely independent. UGSDX charges 1.06%/yr vs 0.72%/yr for CULAX.

Performance

UGSDX vs. CULAX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in U.S. Global Investors U.S. Government Ultra-Short Bond Fund (UGSDX) and Calvert Ultra-Short Duration Income Fund (CULAX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

The year-to-date returns for both investments are quite close, with UGSDX having a 1.32% return and CULAX slightly higher at 1.34%. Over the past 10 years, UGSDX has underperformed CULAX with an annualized return of 1.57%, while CULAX has yielded a comparatively higher 2.47% annualized return.

UGSDX

• 1D: 0.00%
• 1M: 0.25%
• YTD: 1.32%
• 6M: 1.63%
• 1Y: 3.51%
• 3Y*: 4.12%
• 5Y*: 2.30%
• 10Y*: 1.57%

CULAX

• 1D: 0.00%
• 1M: 0.31%
• YTD: 1.34%
• 6M: 1.77%
• 1Y: 4.21%
• 3Y*: 5.11%
• 5Y*: 3.38%
• 10Y*: 2.47%

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

UGSDX vs. CULAX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
UGSDX U.S. Global Investors U.S. Government Ultra-Short Bond Fund	1.32%	3.93%	4.31%	4.15%	-1.66%	-0.44%	0.32%	1.49%	1.18%	1.49%
CULAX Calvert Ultra-Short Duration Income Fund	1.34%	4.55%	5.69%	6.07%	-0.56%	0.43%	0.66%	3.30%	1.15%	1.27%

Correlation

The correlation between UGSDX and CULAX is 0.60, 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	0.60
Correlation (3Y) Calculated over the trailing 3-year period	0.12
Correlation (5Y) Calculated over the trailing 5-year period	0.11
Correlation (10Y) Calculated over the trailing 10-year period	0.11
Correlation (All Time) Calculated using the full available price history since Jan 7, 2014	0.07

Over the past year, UGSDX and CULAX have become more correlated (0.60) than their long-term average of 0.07, meaning their price movements have been converging.

Return for Risk

UGSDX vs. CULAX — Risk / Return Rank

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

CULAX

CULAX Risk / Return Rank: 98
CULAX Sharpe Ratio Rank: 94
CULAX Sortino Ratio Rank: 100
CULAX Omega Ratio Rank: 99
CULAX Calmar Ratio Rank: 99
CULAX Martin Ratio Rank: 99

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.

UGSDX vs. CULAX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for U.S. Global Investors U.S. Government Ultra-Short Bond Fund (UGSDX) and Calvert Ultra-Short Duration Income Fund (CULAX). 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.

	UGSDX	CULAX	Difference
Sharpe ratio: Return per unit of total volatility	3.60	3.22	+0.38
Sortino ratio: Return per unit of downside risk	—	11.38	—
Omega ratio: Gain probability vs. loss probability	—	4.15	—
Calmar ratio: Return relative to maximum drawdown	—	13.98	—
Martin ratio: Return relative to average drawdown	—	56.95	—
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

UGSDX vs. CULAX - Sharpe Ratio Comparison

The current UGSDX Sharpe Ratio is 3.60, which is comparable to the CULAX Sharpe Ratio of 3.22. The chart below compares the historical Sharpe Ratios of UGSDX and CULAX, 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

	UGSDX	CULAX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	3.60	3.22	+0.38
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	1.29	2.53	-1.24
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	1.03	1.75	-0.71
Sharpe Ratio (All Time) Calculated using the full available price history	0.76	2.07	-1.31

Drawdowns

UGSDX vs. CULAX - Drawdown Comparison

The maximum UGSDX drawdown since its inception was -2.83%, smaller than the maximum CULAX drawdown of -7.40%. Use the drawdown chart below to compare losses from any high point for UGSDX and CULAX.

Drawdown Indicators

	UGSDX	CULAX	Difference
Max Drawdown Largest peak-to-trough decline	-2.83%	-7.40%	+4.57%
Max Drawdown (1Y) Largest decline over 1 year	0.00%	-0.30%	+0.30%
Max Drawdown (3Y) Largest decline over 3 years	-0.51%	-0.30%	-0.21%
Max Drawdown (5Y) Largest decline over 5 years	-2.83%	-2.19%	-0.64%
Max Drawdown (10Y) Largest decline over 10 years	-2.83%	-7.40%	+4.57%
Current Drawdown Current decline from peak	0.00%	0.00%	0.00%
Average Drawdown Average peak-to-trough decline	-0.30%	-0.21%	-0.09%
Ulcer Index Depth and duration of drawdowns from previous peaks	0.00%	0.07%	-0.07%

Volatility

UGSDX vs. CULAX - Volatility Comparison

The current volatility for U.S. Global Investors U.S. Government Ultra-Short Bond Fund (UGSDX) is 0.25%, while Calvert Ultra-Short Duration Income Fund (CULAX) has a volatility of 0.31%. This indicates that UGSDX experiences smaller price fluctuations and is considered to be less risky than CULAX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	UGSDX	CULAX	Difference
Volatility (1M) Calculated over the trailing 1-month period	0.25%	0.31%	-0.06%
Volatility (6M) Calculated over the trailing 6-month period	0.65%	0.84%	-0.19%
Volatility (1Y) Calculated over the trailing 1-year period	0.98%	1.32%	-0.34%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	1.79%	1.35%	+0.44%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	1.52%	1.42%	+0.10%

UGSDX vs. CULAX - Expense Ratio Comparison

UGSDX has a 1.06% expense ratio, which is higher than CULAX's 0.72% expense ratio.

Dividends

UGSDX vs. CULAX - Dividend Comparison

UGSDX's dividend yield for the trailing twelve months is around 3.45%, less than CULAX's 3.91% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
CULAX Calvert Ultra-Short Duration Income Fund	3.91%	4.13%	4.90%	4.52%	1.47%	0.64%	1.25%	2.44%	2.10%	1.13%	1.10%	0.66%
UGSDX U.S. Global Investors U.S. Government Ultra-Short Bond Fund	3.45%	3.85%	4.23%	3.55%	0.87%	0.06%	0.32%	1.48%	1.17%	1.48%	0.44%	0.44%

Frequently Asked Questions

Can I hold both UGSDX and CULAX in my portfolio?

UGSDX and CULAX have a correlation of 0.60, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, UGSDX or CULAX?

CULAX has higher volatility (0.31%) compared to UGSDX (0.25%). In terms of maximum drawdown, UGSDX dropped -2.83% vs CULAX's -7.40%.

Which has better risk-adjusted returns?

UGSDX currently has the higher Sharpe Ratio (3.60 vs 3.22), 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.