DMTFX vs. OIFIX

Last updated Jun 4, 2026

DMTFX (Delaware Tax Free USA Fund) and OIFIX (Optimum Fixed Income Fund) are both mutual funds - DMTFX is a Municipal Bonds fund managed by Delaware Funds, while OIFIX is a Intermediate Core-Plus Bond fund managed by Delaware Funds. Over the past 10 years, DMTFX returned 2.68%/yr vs 2.05%/yr for OIFIX. A 0.51 correlation means they provide meaningful diversification when combined. Both charge a 0.80% expense ratio.

Performance

DMTFX vs. OIFIX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Delaware Tax Free USA Fund (DMTFX) and Optimum Fixed Income Fund (OIFIX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, DMTFX achieves a 2.21% return, which is significantly higher than OIFIX's 0.24% return. Over the past 10 years, DMTFX has outperformed OIFIX with an annualized return of 2.68%, while OIFIX has yielded a comparatively lower 2.05% annualized return.

DMTFX

• 1D: 0.30%
• 1M: 1.33%
• YTD: 2.21%
• 6M: 2.40%
• 1Y: 7.59%
• 3Y*: 4.54%
• 5Y*: 0.35%
• 10Y*: 2.68%

OIFIX

• 1D: 0.00%
• 1M: 0.48%
• YTD: 0.24%
• 6M: 0.27%
• 1Y: 5.79%
• 3Y*: 4.33%
• 5Y*: 0.02%
• 10Y*: 2.05%

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

DMTFX vs. OIFIX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
DMTFX Delaware Tax Free USA Fund	2.21%	2.13%	3.17%	10.72%	-16.20%	5.19%	8.85%	8.97%	0.29%	7.19%
OIFIX Optimum Fixed Income Fund	0.24%	7.64%	1.49%	5.90%	-13.96%	-1.78%	11.14%	8.63%	-0.70%	4.50%

Correlation

The correlation between DMTFX and OIFIX is 0.56, 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	0.56
Correlation (3Y) Calculated over the trailing 3-year period	0.58
Correlation (5Y) Calculated over the trailing 5-year period	0.55
Correlation (10Y) Calculated over the trailing 10-year period	0.49
Correlation (All Time) Calculated using the full available price history since Jul 24, 2003	0.51

The correlation between DMTFX and OIFIX has been stable across timeframes, ranging from 0.49 to 0.58 - a consistent structural relationship.

Return for Risk

DMTFX vs. OIFIX — Risk / Return Rank

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

DMTFX

DMTFX Risk / Return Rank: 40
DMTFX Sharpe Ratio Rank: 41
DMTFX Sortino Ratio Rank: 47
DMTFX Omega Ratio Rank: 54
DMTFX Calmar Ratio Rank: 32
DMTFX Martin Ratio Rank: 25

OIFIX

OIFIX Risk / Return Rank: 27
OIFIX Sharpe Ratio Rank: 27
OIFIX Sortino Ratio Rank: 28
OIFIX Omega Ratio Rank: 26
OIFIX Calmar Ratio Rank: 28
OIFIX Martin Ratio Rank: 25

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.

DMTFX vs. OIFIX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Delaware Tax Free USA Fund (DMTFX) and Optimum Fixed Income Fund (OIFIX). 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.

	DMTFX	OIFIX	Difference
Sharpe ratio: Return per unit of total volatility	1.86	1.47	+0.39
Sortino ratio: Return per unit of downside risk	2.88	2.19	+0.69
Omega ratio: Gain probability vs. loss probability	1.40	1.27	+0.14
Calmar ratio: Return relative to maximum drawdown	2.13	1.96	+0.17
Martin ratio: Return relative to average drawdown	6.22	6.14	+0.09
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

DMTFX vs. OIFIX - Sharpe Ratio Comparison

The current DMTFX Sharpe Ratio is 1.86, which is comparable to the OIFIX Sharpe Ratio of 1.47. The chart below compares the historical Sharpe Ratios of DMTFX and OIFIX, 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

	DMTFX	OIFIX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	1.86	1.47	+0.39
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.05	0.00	+0.05
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.45	0.42	+0.02
Sharpe Ratio (All Time) Calculated using the full available price history	0.97	0.88	+0.09

Drawdowns

DMTFX vs. OIFIX - Drawdown Comparison

The maximum DMTFX drawdown since its inception was -21.92%, which is greater than OIFIX's maximum drawdown of -19.46%. Use the drawdown chart below to compare losses from any high point for DMTFX and OIFIX.

Drawdown Indicators

	DMTFX	OIFIX	Difference
Max Drawdown Largest peak-to-trough decline	-21.92%	-19.46%	-2.46%
Max Drawdown (1Y) Largest decline over 1 year	-3.60%	-2.96%	-0.64%
Max Drawdown (3Y) Largest decline over 3 years	-11.32%	-6.67%	-4.65%
Max Drawdown (5Y) Largest decline over 5 years	-21.92%	-19.30%	-2.62%
Max Drawdown (10Y) Largest decline over 10 years	-21.92%	-19.46%	-2.46%
Current Drawdown Current decline from peak	-0.25%	-1.99%	+1.74%
Average Drawdown Average peak-to-trough decline	-2.55%	-2.93%	+0.38%
Ulcer Index Depth and duration of drawdowns from previous peaks	1.23%	0.95%	+0.28%

Volatility

DMTFX vs. OIFIX - Volatility Comparison

Delaware Tax Free USA Fund (DMTFX) and Optimum Fixed Income Fund (OIFIX) have volatilities of 1.48% and 1.43%, respectively, indicating that both stocks experience similar levels of price fluctuations. This suggests that the risk associated with both stocks, as measured by volatility, is nearly the same. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	DMTFX	OIFIX	Difference
Volatility (1M) Calculated over the trailing 1-month period	1.48%	1.43%	+0.05%
Volatility (6M) Calculated over the trailing 6-month period	2.89%	2.80%	+0.09%
Volatility (1Y) Calculated over the trailing 1-year period	4.16%	3.96%	+0.20%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	6.61%	5.90%	+0.71%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	6.00%	4.87%	+1.13%

DMTFX vs. OIFIX - Expense Ratio Comparison

Both DMTFX and OIFIX have an expense ratio of 0.80%.

Dividends

DMTFX vs. OIFIX - Dividend Comparison

DMTFX's dividend yield for the trailing twelve months is around 4.26%, more than OIFIX's 3.85% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
DMTFX Delaware Tax Free USA Fund	4.26%	5.69%	4.77%	3.53%	3.67%	4.00%	4.24%	4.44%	3.64%	4.74%	4.70%	3.63%
OIFIX Optimum Fixed Income Fund	3.85%	3.86%	3.97%	3.23%	3.42%	2.21%	6.88%	3.22%	2.43%	2.50%	2.17%	3.24%

Frequently Asked Questions

Can I hold both DMTFX and OIFIX in my portfolio?

DMTFX and OIFIX have a correlation of 0.56, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, DMTFX or OIFIX?

DMTFX has higher volatility (1.48%) compared to OIFIX (1.43%). In terms of maximum drawdown, DMTFX dropped -21.92% vs OIFIX's -19.46%.

Which has better risk-adjusted returns?

DMTFX currently has the higher Sharpe Ratio (1.86 vs 1.47), 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.