MAMTX vs. AFB

Last updated Jun 5, 2026

MAMTX (Blackrock Strategic Municipal Opportunities Fund Of Blackrock Municipal Series Trust) and AFB (AllianceBernstein National Municipal Income Fund) are both Municipal Bonds funds. Over the past 10 years, MAMTX returned 2.14%/yr vs 1.66%/yr for AFB. At a 0.21 correlation, their price movements are largely independent. MAMTX charges 0.55%/yr vs 1.56%/yr for AFB.

Performance

MAMTX vs. AFB - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Blackrock Strategic Municipal Opportunities Fund Of Blackrock Municipal Series Trust (MAMTX) and AllianceBernstein National Municipal Income Fund (AFB). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, MAMTX achieves a 2.14% return, which is significantly lower than AFB's 6.96% return. Over the past 10 years, MAMTX has outperformed AFB with an annualized return of 2.14%, while AFB has yielded a comparatively lower 1.66% annualized return.

MAMTX

• 1D: 0.00%
• 1M: 0.90%
• YTD: 2.14%
• 6M: 2.48%
• 1Y: 7.22%
• 3Y*: 4.34%
• 5Y*: 0.61%
• 10Y*: 2.14%

AFB

• 1D: 0.72%
• 1M: 1.99%
• YTD: 6.96%
• 6M: 6.47%
• 1Y: 16.97%
• 3Y*: 7.41%
• 5Y*: -1.12%
• 10Y*: 1.66%

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

MAMTX vs. AFB - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
MAMTX Blackrock Strategic Municipal Opportunities Fund Of Blackrock Municipal Series Trust	2.14%	3.97%	3.90%	4.89%	-12.11%	5.84%	0.58%	6.81%	1.27%	8.05%
AFB AllianceBernstein National Municipal Income Fund	6.96%	4.41%	4.10%	7.41%	-25.93%	7.25%	7.80%	20.13%	-5.43%	6.15%

Correlation

The correlation between MAMTX and AFB is 0.42, which is low. Their price movements are largely independent, making them effective diversification partners.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	0.42
Correlation (3Y) Calculated over the trailing 3-year period	0.44
Correlation (5Y) Calculated over the trailing 5-year period	0.36
Correlation (10Y) Calculated over the trailing 10-year period	0.24
Correlation (All Time) Calculated using the full available price history since Jan 30, 2002	0.21

Over the past year, MAMTX and AFB have become more correlated (0.42) than their long-term average of 0.21, meaning their price movements have been converging.

Return for Risk

MAMTX vs. AFB — Risk / Return Rank

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

MAMTX

MAMTX Risk / Return Rank: 61
MAMTX Sharpe Ratio Rank: 63
MAMTX Sortino Ratio Rank: 74
MAMTX Omega Ratio Rank: 82
MAMTX Calmar Ratio Rank: 47
MAMTX Martin Ratio Rank: 41

AFB

AFB Risk / Return Rank: 62
AFB Sharpe Ratio Rank: 57
AFB Sortino Ratio Rank: 73
AFB Omega Ratio Rank: 62
AFB Calmar Ratio Rank: 59
AFB Martin Ratio Rank: 56

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.

MAMTX vs. AFB - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Blackrock Strategic Municipal Opportunities Fund Of Blackrock Municipal Series Trust (MAMTX) and AllianceBernstein National Municipal Income Fund (AFB). 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.

	MAMTX	AFB	Difference
Sharpe ratio: Return per unit of total volatility	2.32	2.17	+0.16
Sortino ratio: Return per unit of downside risk	3.60	3.52	+0.09
Omega ratio: Gain probability vs. loss probability	1.55	1.42	+0.12
Calmar ratio: Return relative to maximum drawdown	2.58	2.86	-0.28
Martin ratio: Return relative to average drawdown	8.67	10.80	-2.13
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

MAMTX vs. AFB - Sharpe Ratio Comparison

The current MAMTX Sharpe Ratio is 2.32, which is comparable to the AFB Sharpe Ratio of 2.17. The chart below compares the historical Sharpe Ratios of MAMTX and AFB, 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

	MAMTX	AFB	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	2.32	2.17	+0.16
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.13	-0.10	+0.23
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.44	0.15	+0.29
Sharpe Ratio (All Time) Calculated using the full available price history	1.19	0.33	+0.87

Drawdowns

MAMTX vs. AFB - Drawdown Comparison

The maximum MAMTX drawdown since its inception was -16.83%, smaller than the maximum AFB drawdown of -50.98%. Use the drawdown chart below to compare losses from any high point for MAMTX and AFB.

Drawdown Indicators

	MAMTX	AFB	Difference
Max Drawdown Largest peak-to-trough decline	-16.83%	-50.98%	+34.15%
Max Drawdown (1Y) Largest decline over 1 year	-2.85%	-5.96%	+3.11%
Max Drawdown (3Y) Largest decline over 3 years	-6.33%	-16.32%	+9.99%
Max Drawdown (5Y) Largest decline over 5 years	-16.83%	-35.17%	+18.34%
Max Drawdown (10Y) Largest decline over 10 years	-16.83%	-35.17%	+18.34%
Current Drawdown Current decline from peak	0.00%	-8.92%	+8.92%
Average Drawdown Average peak-to-trough decline	-2.06%	-8.98%	+6.92%
Ulcer Index Depth and duration of drawdowns from previous peaks	0.85%	1.58%	-0.73%

Volatility

MAMTX vs. AFB - Volatility Comparison

The current volatility for Blackrock Strategic Municipal Opportunities Fund Of Blackrock Municipal Series Trust (MAMTX) is 1.13%, while AllianceBernstein National Municipal Income Fund (AFB) has a volatility of 2.69%. This indicates that MAMTX experiences smaller price fluctuations and is considered to be less risky than AFB based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	MAMTX	AFB	Difference
Volatility (1M) Calculated over the trailing 1-month period	1.13%	2.69%	-1.56%
Volatility (6M) Calculated over the trailing 6-month period	2.27%	5.76%	-3.49%
Volatility (1Y) Calculated over the trailing 1-year period	3.17%	7.88%	-4.71%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	4.78%	10.94%	-6.16%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	4.84%	11.24%	-6.40%

MAMTX vs. AFB - Expense Ratio Comparison

MAMTX has a 0.55% expense ratio, which is lower than AFB's 1.56% expense ratio.

Dividends

MAMTX vs. AFB - Dividend Comparison

MAMTX's dividend yield for the trailing twelve months is around 3.90%, less than AFB's 5.45% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
AFB AllianceBernstein National Municipal Income Fund	5.45%	4.72%	3.83%	3.62%	5.26%	4.32%	4.18%	3.93%	4.53%	4.71%	5.34%	5.80%
MAMTX Blackrock Strategic Municipal Opportunities Fund Of Blackrock Municipal Series Trust	3.90%	5.00%	4.23%	2.70%	1.96%	2.00%	2.39%	2.83%	4.74%	2.89%	3.91%	2.84%

Frequently Asked Questions

Can I hold both MAMTX and AFB in my portfolio?

MAMTX and AFB have a correlation of 0.42, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, MAMTX or AFB?

AFB has higher volatility (2.69%) compared to MAMTX (1.13%). In terms of maximum drawdown, MAMTX dropped -16.83% vs AFB's -50.98%.

Which has better risk-adjusted returns?

MAMTX currently has the higher Sharpe Ratio (2.32 vs 2.17), 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.