SUB vs. DFNM

Last updated Jun 23, 2026

SUB (iShares Short-Term National Muni Bond ETF) and DFNM (Dimensional National Municipal Bond ETF) are both Municipal Bonds funds. SUB is passively managed, while DFNM is actively managed. Over the past 3 years, SUB returned 3.08%/yr vs 3.20%/yr for DFNM. A 0.67 correlation means they provide meaningful diversification when combined. SUB charges 0.07%/yr vs 0.17%/yr for DFNM.

Performance

SUB vs. DFNM - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in iShares Short-Term National Muni Bond ETF (SUB) and Dimensional National Municipal Bond ETF (DFNM). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, SUB achieves a 0.93% return, which is significantly lower than DFNM's 1.44% return.

SUB

• 1D: 0.00%
• 1M: 0.52%
• YTD: 0.93%
• 6M: 1.10%
• 1Y: 2.93%
• 3Y*: 3.08%
• 5Y*: 1.51%
• 10Y*: 1.46%

DFNM

• 1D: -0.01%
• 1M: 0.92%
• YTD: 1.44%
• 6M: 1.52%
• 1Y: 5.19%
• 3Y*: 3.20%
• 5Y*: —
• 10Y*: —

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

SUB vs. DFNM - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021
SUB iShares Short-Term National Muni Bond ETF	0.93%	3.64%	2.17%	2.91%	-2.05%	0.08%
DFNM Dimensional National Municipal Bond ETF	1.44%	3.87%	1.19%	3.97%	-4.02%	0.40%

Correlation

The correlation between SUB and DFNM is 0.52, 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	0.52
Correlation (3Y) Calculated over the trailing 3-year period	0.62
Correlation (All Time) Calculated using the full available price history since Nov 16, 2021	0.67

The correlation between SUB and DFNM shifts across timeframes, from 0.52 (1 year) to 0.67 (all time), reflecting how their relationship changes across market environments.

Return for Risk

SUB vs. DFNM — Risk / Return Rank

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

SUB

SUB Risk / Return Rank: 82
SUB Sharpe Ratio Rank: 90
SUB Sortino Ratio Rank: 92
SUB Omega Ratio Rank: 94
SUB Calmar Ratio Rank: 74
SUB Martin Ratio Rank: 60

DFNM

DFNM Risk / Return Rank: 80
DFNM Sharpe Ratio Rank: 91
DFNM Sortino Ratio Rank: 93
DFNM Omega Ratio Rank: 95
DFNM Calmar Ratio Rank: 59
DFNM Martin Ratio Rank: 59

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.

SUB vs. DFNM - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for iShares Short-Term National Muni Bond ETF (SUB) and Dimensional National Municipal Bond ETF (DFNM). 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.

	SUB	DFNM	Difference
Sharpe ratio: Return per unit of total volatility	2.92	3.04	-0.11
Sortino ratio: Return per unit of downside risk	4.21	4.39	-0.17
Omega ratio: Gain probability vs. loss probability	1.64	1.70	-0.06
Calmar ratio: Return relative to maximum drawdown	3.65	2.84	+0.82
Martin ratio: Return relative to average drawdown	10.32	10.19	+0.13

SUB vs. DFNM - Sharpe Ratio Comparison

The current SUB Sharpe Ratio is 2.92, which is comparable to the DFNM Sharpe Ratio of 3.04. The chart below compares the historical Sharpe Ratios of SUB and DFNM, 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

SUB vs. DFNM - Drawdown Comparison

The maximum SUB drawdown since its inception was -9.46%, which is greater than DFNM's maximum drawdown of -6.99%. Use the drawdown chart below to compare losses from any high point for SUB and DFNM.

Drawdown Indicators

	SUB	DFNM	Difference
Max Drawdown Largest peak-to-trough decline	-9.46%	-6.99%	-2.47%
Max Drawdown (1Y) Largest decline over 1 year	-0.81%	-1.84%	+1.03%
Max Drawdown (3Y) Largest decline over 3 years	-1.23%	-2.82%	+1.59%
Max Drawdown (5Y) Largest decline over 5 years	-4.35%	—	—
Max Drawdown (10Y) Largest decline over 10 years	-9.46%	—	—
Current Drawdown Current decline from peak	0.00%	-0.22%	+0.22%
Average Drawdown Average peak-to-trough decline	-0.91%	-1.94%	+1.03%
Ulcer Index Depth and duration of drawdowns from previous peaks	0.28%	0.51%	-0.23%

Volatility

SUB vs. DFNM - Volatility Comparison

The current volatility for iShares Short-Term National Muni Bond ETF (SUB) is 0.25%, while Dimensional National Municipal Bond ETF (DFNM) has a volatility of 0.38%. This indicates that SUB experiences smaller price fluctuations and is considered to be less risky than DFNM based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	SUB	DFNM	Difference
Volatility (1M) Calculated over the trailing 1-month period	0.25%	0.38%	-0.13%
Volatility (6M) Calculated over the trailing 6-month period	0.80%	1.29%	-0.49%
Volatility (1Y) Calculated over the trailing 1-year period	1.01%	1.72%	-0.71%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	1.64%	2.53%	-0.89%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	2.60%	2.53%	+0.07%

SUB vs. DFNM - Expense Ratio Comparison

SUB has a 0.07% expense ratio, which is lower than DFNM's 0.17% expense ratio. Despite the difference, both funds are considered low-cost compared to the broader market, where average expense ratios usually range from 0.3% to 0.9%.

Dividends

SUB vs. DFNM - Dividend Comparison

SUB's dividend yield for the trailing twelve months is around 2.52%, less than DFNM's 2.89% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
DFNM Dimensional National Municipal Bond ETF	2.89%	2.94%	2.74%	2.39%	1.16%	0.05%	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%
SUB iShares Short-Term National Muni Bond ETF	2.52%	2.42%	2.10%	1.73%	0.86%	0.72%	1.23%	1.58%	1.32%	0.95%	0.75%	0.77%

Frequently Asked Questions

Can I hold both SUB and DFNM in my portfolio?

SUB and DFNM have a correlation of 0.52, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, SUB or DFNM?

DFNM has higher volatility (0.38%) compared to SUB (0.25%). In terms of maximum drawdown, SUB dropped -9.46% vs DFNM's -6.99%.

Which ETF is better, SUB or DFNM?

On 3-year performance, DFNM leads with 3.20% vs 3.08% for SUB. On fees, SUB is cheaper at 0.07% per year. On volatility, SUB has been the lower-risk option at 0.25%. The better choice depends on whether you care most about return, fees, risk, or income.

Which ETF has performed better, SUB or DFNM?

Over the 3-year period, DFNM has performed better with a 3.20% return vs 3.08%. Past performance does not guarantee future results, so compare this with risk, fees, and fund exposure.

Which ETF is cheaper, SUB or DFNM?

SUB is cheaper with a 0.07% expense ratio, compared with 0.17% for DFNM.

Which ETF pays a higher dividend yield, SUB or DFNM?

DFNM has the higher dividend yield at 2.89%, compared with 2.52% for SUB.

What is the main difference between SUB and DFNM?

They also come from different issuers: iShares and Dimensional. Their fees differ too: 0.07% for SUB and 0.17% for DFNM.

Which has better risk-adjusted returns?

DFNM currently has the higher Sharpe Ratio (3.04 vs 2.92), 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.