CULAX vs. TRBUX

Last updated Jul 14, 2026

CULAX (Calvert Ultra-Short Duration Income Fund) and TRBUX (T. Rowe Price Ultra Short-Term Bond Fund) are both Ultrashort Bond funds. Over the past 10 years, CULAX returned 2.48%/yr vs 3.92%/yr for TRBUX. At a 0.22 correlation, their price movements are largely independent. CULAX charges 0.72%/yr vs 0.31%/yr for TRBUX.

Performance

CULAX vs. TRBUX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Calvert Ultra-Short Duration Income Fund (CULAX) and T. Rowe Price Ultra Short-Term Bond Fund (TRBUX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, CULAX achieves a 1.66% return, which is significantly lower than TRBUX's 2.12% return. Over the past 10 years, CULAX has underperformed TRBUX with an annualized return of 2.48%, while TRBUX has yielded a comparatively higher 3.92% annualized return.

CULAX

• 1D: 0.00%
• 1M: 0.31%
• 6M: 1.66%
• YTD: 1.66%
• 1Y: 4.05%
• 3Y*: 5.05%
• 5Y*: 3.44%
• 10Y*: 2.48%

TRBUX

• 1D: 0.00%
• 1M: 0.17%
• 6M: 2.12%
• YTD: 2.12%
• 1Y: 4.94%
• 3Y*: 8.42%
• 5Y*: 5.61%
• 10Y*: 3.92%

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

CULAX vs. TRBUX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
CULAX Calvert Ultra-Short Duration Income Fund	1.66%	4.55%	5.69%	6.07%	-0.56%	0.43%	0.66%	3.30%	1.15%	1.27%
TRBUX T. Rowe Price Ultra Short-Term Bond Fund	2.12%	6.49%	11.12%	10.12%	-1.28%	0.22%	3.11%	3.60%	1.88%	1.83%

Correlation

The correlation between CULAX and TRBUX is -0.05, meaning there is essentially no relationship between their price movements. Each responds to its own set of market drivers, making them strong candidates for combining in a diversified portfolio.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	-0.05
Correlation (3Y) Calculated over the trailing 3-year period	0.22
Correlation (5Y) Calculated over the trailing 5-year period	0.27
Correlation (10Y) Calculated over the trailing 10-year period	0.27
Correlation (All Time) Calculated using the full available price history since Oct 3, 2013	0.22

The correlation between CULAX and TRBUX shifts across timeframes, from -0.05 (1 year) to 0.27 (5 years), reflecting how their relationship changes across market environments.

Return for Risk

CULAX vs. TRBUX — Risk / Return Rank

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

CULAX

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

TRBUX

TRBUX Risk / Return Rank: 98
TRBUX Sharpe Ratio Rank: 97
TRBUX Sortino Ratio Rank: 98
TRBUX Omega Ratio Rank: 99
TRBUX Calmar Ratio Rank: 99
TRBUX 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.

CULAX vs. TRBUX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Calvert Ultra-Short Duration Income Fund (CULAX) and T. Rowe Price Ultra Short-Term Bond Fund (TRBUX). 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.

Values are calculated on a 1-year rolling basis and updated daily. Risk-adjusted metrics are more stable over longer periods — use the period switch above to explore them.

	CULAX	TRBUX	Difference
Sharpe ratio: Return per unit of total volatility	3.23	3.01	+0.22
Sortino ratio: Return per unit of downside risk	11.43	6.93	+4.50
Omega ratio: Gain probability vs. loss probability	4.29	2.89	+1.40
Calmar ratio: Return relative to maximum drawdown	13.47	12.99	+0.48
Martin ratio: Return relative to average drawdown	59.44	48.41	+11.03

CULAX vs. TRBUX - Sharpe Ratio Comparison

The current CULAX Sharpe Ratio is 3.23, which is comparable to the TRBUX Sharpe Ratio of 3.01. The chart below compares the historical Sharpe Ratios of CULAX and TRBUX, calculated using daily returns over the previous 12 months. A higher Sharpe Ratio indicates better risk-adjusted performance relative to the risk-free rate.

Drawdowns

CULAX vs. TRBUX - Drawdown Comparison

The maximum CULAX drawdown since its inception was -7.40%, which is greater than TRBUX's maximum drawdown of -4.15%. Use the drawdown chart below to compare losses from any high point for CULAX and TRBUX.

Drawdown Indicators

	CULAX	TRBUX	Difference
Max Drawdown Largest peak-to-trough decline	-7.40%	-4.15%	-3.25%
Max Drawdown (1Y) Largest decline over 1 year	-0.30%	-0.39%	+0.09%
Max Drawdown (3Y) Largest decline over 3 years	-0.30%	-0.78%	+0.48%
Max Drawdown (5Y) Largest decline over 5 years	-2.19%	-2.66%	+0.47%
Max Drawdown (10Y) Largest decline over 10 years	-7.40%	-4.15%	-3.25%
Current Drawdown Current decline from peak	0.00%	-0.20%	+0.20%
Average Drawdown Average peak-to-trough decline	-0.21%	-0.21%	0.00%
Ulcer Index Depth and duration of drawdowns from previous peaks	0.07%	0.11%	-0.04%

Volatility

CULAX vs. TRBUX - Volatility Comparison

The current volatility for Calvert Ultra-Short Duration Income Fund (CULAX) is 0.37%, while T. Rowe Price Ultra Short-Term Bond Fund (TRBUX) has a volatility of 0.61%. This indicates that CULAX experiences smaller price fluctuations and is considered to be less risky than TRBUX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	CULAX	TRBUX	Difference
Volatility (1M) Calculated over the trailing 1-month period	0.37%	0.61%	-0.24%
Volatility (6M) Calculated over the trailing 6-month period	0.86%	1.28%	-0.42%
Volatility (1Y) Calculated over the trailing 1-year period	1.26%	1.70%	-0.44%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	1.35%	1.81%	-0.46%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	1.42%	1.58%	-0.16%

CULAX vs. TRBUX - Expense Ratio Comparison

CULAX has a 0.72% expense ratio, which is higher than TRBUX's 0.31% expense ratio.

Dividends

CULAX vs. TRBUX - Dividend Comparison

CULAX's dividend yield for the trailing twelve months is around 3.87%, less than TRBUX's 4.82% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
CULAX Calvert Ultra-Short Duration Income Fund	3.87%	4.13%	4.90%	4.52%	1.47%	0.64%	1.25%	2.44%	2.10%	1.13%	1.10%	0.66%
TRBUX T. Rowe Price Ultra Short-Term Bond Fund	4.82%	5.86%	9.30%	7.34%	1.53%	1.21%	1.86%	2.73%	2.47%	1.62%	1.18%	0.81%

Frequently Asked Questions

Can I hold both CULAX and TRBUX in my portfolio?

CULAX and TRBUX have a correlation of -0.05, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, CULAX or TRBUX?

TRBUX has higher volatility (0.61%) compared to CULAX (0.37%). In terms of maximum drawdown, CULAX dropped -7.40% vs TRBUX's -4.15%.

Which has better risk-adjusted returns?

CULAX currently has the higher Sharpe Ratio (3.23 vs 3.01), 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.