CUBIX vs. CULAX

Last updated Jun 4, 2026

CUBIX (Calvert Flexible Bond Fund) and CULAX (Calvert Ultra-Short Duration Income Fund) are both mutual funds - CUBIX is a Nontraditional Bonds fund managed by Calvert Research and Management, while CULAX is a Ultrashort Bond fund managed by Calvert Research and Management. Over the past 10 years, CUBIX returned 4.04%/yr vs 2.47%/yr for CULAX. At a 0.43 correlation, their price movements are largely independent. CUBIX charges 0.66%/yr vs 0.72%/yr for CULAX.

Performance

CUBIX vs. CULAX - Performance Comparison

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

Returns By Period

In the year-to-date period, CUBIX achieves a 0.83% return, which is significantly lower than CULAX's 1.34% return. Over the past 10 years, CUBIX has outperformed CULAX with an annualized return of 4.04%, while CULAX has yielded a comparatively lower 2.47% annualized return.

CUBIX

• 1D: 0.00%
• 1M: 0.46%
• YTD: 0.83%
• 6M: 1.20%
• 1Y: 5.94%
• 3Y*: 6.84%
• 5Y*: 3.76%
• 10Y*: 4.04%

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)

CUBIX vs. CULAX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
CUBIX Calvert Flexible Bond Fund	0.83%	8.23%	6.56%	7.24%	-4.15%	3.82%	4.12%	7.06%	0.43%	3.30%
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 CUBIX and CULAX is 0.47, which is low. Their price movements are largely independent, making them effective diversification partners.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	0.47
Correlation (3Y) Calculated over the trailing 3-year period	0.52
Correlation (5Y) Calculated over the trailing 5-year period	0.52
Correlation (10Y) Calculated over the trailing 10-year period	0.45
Correlation (All Time) Calculated using the full available price history since Oct 2, 2014	0.43

The correlation between CUBIX and CULAX has been stable across timeframes, ranging from 0.43 to 0.52 - a consistent structural relationship.

Return for Risk

CUBIX vs. CULAX — Risk / Return Rank

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

CUBIX

CUBIX Risk / Return Rank: 62
CUBIX Sharpe Ratio Rank: 58
CUBIX Sortino Ratio Rank: 76
CUBIX Omega Ratio Rank: 74
CUBIX Calmar Ratio Rank: 49
CUBIX Martin Ratio Rank: 54

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.

CUBIX vs. CULAX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Calvert Flexible Bond Fund (CUBIX) 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.

	CUBIX	CULAX	Difference
Sharpe ratio: Return per unit of total volatility	2.25	3.22	-0.97
Sortino ratio: Return per unit of downside risk	3.65	11.38	-7.73
Omega ratio: Gain probability vs. loss probability	1.49	4.15	-2.66
Calmar ratio: Return relative to maximum drawdown	2.67	13.98	-11.31
Martin ratio: Return relative to average drawdown	10.91	56.95	-46.04
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

CUBIX vs. CULAX - Sharpe Ratio Comparison

The current CUBIX Sharpe Ratio is 2.25, which is lower than the CULAX Sharpe Ratio of 3.22. The chart below compares the historical Sharpe Ratios of CUBIX 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

	CUBIX	CULAX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	2.25	3.22	-0.97
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	1.30	2.53	-1.23
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	1.44	1.75	-0.31
Sharpe Ratio (All Time) Calculated using the full available price history	1.47	2.07	-0.61

Drawdowns

CUBIX vs. CULAX - Drawdown Comparison

The maximum CUBIX drawdown since its inception was -14.12%, which is greater than CULAX's maximum drawdown of -7.40%. Use the drawdown chart below to compare losses from any high point for CUBIX and CULAX.

Drawdown Indicators

	CUBIX	CULAX	Difference
Max Drawdown Largest peak-to-trough decline	-14.12%	-7.40%	-6.72%
Max Drawdown (1Y) Largest decline over 1 year	-2.26%	-0.30%	-1.96%
Max Drawdown (3Y) Largest decline over 3 years	-2.26%	-0.30%	-1.96%
Max Drawdown (5Y) Largest decline over 5 years	-7.48%	-2.19%	-5.29%
Max Drawdown (10Y) Largest decline over 10 years	-14.12%	-7.40%	-6.72%
Current Drawdown Current decline from peak	-0.35%	0.00%	-0.35%
Average Drawdown Average peak-to-trough decline	-0.95%	-0.21%	-0.74%
Ulcer Index Depth and duration of drawdowns from previous peaks	0.55%	0.07%	+0.48%

Volatility

CUBIX vs. CULAX - Volatility Comparison

Calvert Flexible Bond Fund (CUBIX) has a higher volatility of 1.19% compared to Calvert Ultra-Short Duration Income Fund (CULAX) at 0.31%. This indicates that CUBIX's price experiences larger fluctuations and is considered to be riskier than CULAX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	CUBIX	CULAX	Difference
Volatility (1M) Calculated over the trailing 1-month period	1.19%	0.31%	+0.88%
Volatility (6M) Calculated over the trailing 6-month period	2.17%	0.84%	+1.33%
Volatility (1Y) Calculated over the trailing 1-year period	2.69%	1.32%	+1.37%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	2.91%	1.35%	+1.56%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	2.82%	1.42%	+1.40%

CUBIX vs. CULAX - Expense Ratio Comparison

CUBIX has a 0.66% expense ratio, which is lower than CULAX's 0.72% expense ratio.

Dividends

CUBIX vs. CULAX - Dividend Comparison

CUBIX's dividend yield for the trailing twelve months is around 4.91%, more than CULAX's 3.91% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
CUBIX Calvert Flexible Bond Fund	4.91%	4.93%	5.50%	3.95%	4.75%	3.58%	2.85%	3.35%	3.33%	3.41%	4.48%	3.25%
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%

Frequently Asked Questions

Can I hold both CUBIX and CULAX in my portfolio?

CUBIX and CULAX have a correlation of 0.47, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, CUBIX or CULAX?

CUBIX has higher volatility (1.19%) compared to CULAX (0.31%). In terms of maximum drawdown, CUBIX dropped -14.12% vs CULAX's -7.40%.

Which has better risk-adjusted returns?

CULAX currently has the higher Sharpe Ratio (3.22 vs 2.25), 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.