MFSM vs. ZMUN

Last updated Jun 3, 2026

MFSM (MFS Active Intermediate Muni Bond ETF) and ZMUN (F/m Ultrashort Tax-Free Municipal ETF) are both Municipal Bonds funds. MFSM is actively managed, while ZMUN is passively managed. At a 0.14 correlation, their price movements are largely independent. MFSM charges 0.34%/yr vs 0.30%/yr for ZMUN.

Performance

MFSM vs. ZMUN - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in MFS Active Intermediate Muni Bond ETF (MFSM) and F/m Ultrashort Tax-Free Municipal ETF (ZMUN). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, MFSM achieves a 1.76% return, which is significantly higher than ZMUN's 1.59% return.

MFSM

• 1D: 0.11%
• 1M: 0.64%
• YTD: 1.76%
• 6M: 2.32%
• 1Y: 7.56%
• 3Y*: —
• 5Y*: —
• 10Y*: —

ZMUN

• 1D: 0.07%
• 1M: 0.24%
• YTD: 1.59%
• 6M: 1.90%
• 1Y: —
• 3Y*: —
• 5Y*: —
• 10Y*: —

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

MFSM vs. ZMUN - Yearly Performance Comparison

	2026 (YTD)	2025
MFSM MFS Active Intermediate Muni Bond ETF	1.76%	1.78%
ZMUN F/m Ultrashort Tax-Free Municipal ETF	1.59%	0.73%

Correlation

The correlation between MFSM and ZMUN is 0.14, which is low. Their price movements are largely independent, making them effective diversification partners.

	Correlation
Correlation (All Time) Calculated using the full available price history since Oct 1, 2025	0.14

Return for Risk

MFSM vs. ZMUN — Risk / Return Rank

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

MFSM

MFSM Risk / Return Rank: 76
MFSM Sharpe Ratio Rank: 85
MFSM Sortino Ratio Rank: 90
MFSM Omega Ratio Rank: 91
MFSM Calmar Ratio Rank: 55
MFSM Martin Ratio Rank: 58

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.

MFSM vs. ZMUN - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for MFS Active Intermediate Muni Bond ETF (MFSM) and F/m Ultrashort Tax-Free Municipal ETF (ZMUN). 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.

	MFSM	ZMUN	Difference
Sharpe ratio Return per unit of total volatility	2.84	—	—
Sortino ratio Return per unit of downside risk	4.35	—	—
Omega ratio Gain probability vs. loss probability	1.62	—	—
Calmar ratio Return relative to maximum drawdown	2.80	—	—
Martin ratio Return relative to average drawdown	10.40	—	—
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

Sharpe Ratios by Period

	MFSM	ZMUN	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	2.84	—	—
Sharpe Ratio (All Time) Calculated using the full available price history	1.12	6.55	-5.44

Drawdowns

MFSM vs. ZMUN - Drawdown Comparison

The maximum MFSM drawdown since its inception was -3.86%, which is greater than ZMUN's maximum drawdown of -0.09%. Use the drawdown chart below to compare losses from any high point for MFSM and ZMUN.

Drawdown Indicators

	MFSM	ZMUN	Difference
Max Drawdown Largest peak-to-trough decline	-3.86%	-0.09%	-3.77%
Max Drawdown (1Y) Largest decline over 1 year	-2.65%	—	—
Current Drawdown Current decline from peak	-0.49%	0.00%	-0.49%
Average Drawdown Average peak-to-trough decline	-0.88%	-0.01%	-0.87%
Ulcer Index Depth and duration of drawdowns from previous peaks	0.71%	—	—

Volatility

Volatility by Period

	MFSM	ZMUN	Difference
Volatility (1M) Calculated over the trailing 1-month period	0.93%	—	—
Volatility (6M) Calculated over the trailing 6-month period	1.97%	—	—
Volatility (1Y) Calculated over the trailing 1-year period	2.67%	0.54%	+2.13%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	3.45%	0.54%	+2.91%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	3.45%	0.54%	+2.91%

MFSM vs. ZMUN - Expense Ratio Comparison

MFSM has a 0.34% expense ratio, which is higher than ZMUN's 0.30% expense ratio.

Dividends

MFSM vs. ZMUN - Dividend Comparison

MFSM's dividend yield for the trailing twelve months is around 3.55%, more than ZMUN's 2.28% yield.

Position	TTM	2025	2024
MFSM MFS Active Intermediate Muni Bond ETF	3.55%	3.53%	0.23%
ZMUN F/m Ultrashort Tax-Free Municipal ETF	2.28%	0.70%	0.00%

Frequently Asked Questions

Can I hold both MFSM and ZMUN in my portfolio?

MFSM and ZMUN have a correlation of 0.14, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which ETF is better, MFSM or ZMUN?

On fees, ZMUN is cheaper at 0.30% per year. The better choice depends on whether you care most about return, fees, risk, or income.

Which ETF is cheaper, MFSM or ZMUN?

ZMUN is cheaper with a 0.30% expense ratio, compared with 0.34% for MFSM.

Which ETF pays a higher dividend yield, MFSM or ZMUN?

MFSM has the higher dividend yield at 3.55%, compared with 2.28% for ZMUN.

What is the main difference between MFSM and ZMUN?

They also come from different issuers: MFS and F/m Investments. Their fees differ too: 0.34% for MFSM and 0.30% for ZMUN.