Fund Evaluator:
BlackRock Short Duration Muni Inv A1 (MDLMX)
Follow This Fund
Best Performing in Muni National Short Over the Last Year
| 4.7% | PGIM Short Duration Muni Z (PDSZX) |
| 4.3% | BlackRock Short Duration Muni Inv A1 (MDLMX) |
| 4.0% | Vanguard Ltd-Term Tx-Ex Adm (VMLUX) |
| 3.9% | Vanguard Ltd-Term Tx-Ex (VMLTX) |
| 3.8% | T. Rowe Price Tax-Free Shrt-Interm (PRFSX) |
Fund Details
BlackRock Short Duration Muni Inv A1 Overview
BlackRock Short Duration Muni Inv A1 (MDLMX) is an actively managed Municipal Bond Muni National Short fund. BlackRock launched the fund in 1994.
The investment seeks to provide shareholders with as high a level of income exempt from Federal income taxes as is consistent with the investment policies of the fund. Under normal circumstances, the Short Duration Fund seeks to achieve its objective by investing at least 80% of its assets in municipal bonds. The short duration fund invests primarily in investment grade municipal bonds or municipal notes, including variable rate demand obligations.
About BlackRock Short Duration Muni Inv A1 (MDLMX)
There are 4 members of the management team with an average tenure of 3.97 years: Christian Romaglino (2021), Kevin Maloney (2024), Kristi Manidis (2019), Alicia De Lorenzo (2024). Management tenure is more important for actively managed funds than passive index funds.
The fund has 2 primary benchmarks: Bloomberg Municipal TR USD index with a weighting of 100% and Bloomberg Municipal 1-5 Yr TR USD index with a weighting of 100%. BlackRock Short Duration Muni Inv A1 has 223 securities in its portfolio. The top 10 holdings constitute 18.8% of the fund’s assets. The fund meets the SEC requirement of being classified as a diversified fund. The fund is not considered to have an ESG focus with its investment selection and management.
BlackRock Short Duration Muni Inv A1 is part of the Fixed Income global asset class and is within the Municipal Bond fund group. BlackRock Short Duration Muni Inv A1 has 0.0% of its portfolio invested in foreign issues. The overall assets allocated to domestic stock is 0.0%. There is 0.0% allocated to foreign stock, and 0.0% is allocated to preferred stocks. The bond allocation as a percentage of total assets is 95.8% (95.8% domestic bond, 0.0% foreign bond and 0.0% convertible bond). BlackRock Short Duration Muni Inv A1 has 4.2% of the portfolio in cash.
Assets Under Management
The fund has $7 million in total assets, which is below the $630 million average for the Muni National Short category. Normally, lower assets under management translates to higher average expense ratios, and greater total assets are desired. However, for some investment categories, such as small-cap investing, it may be difficult for the manager to fully employ the desired active strategy if assets grow too large or too quickly.
MDLMX Performance and Fees
The expense ratio measures how much of a fund’s assets are used for administrative expenses and operating expenses, including adviser fees and fees for the transfer agent and custodial services. The BlackRock Short Duration Muni Inv A1 expense ratio is average compared to funds in the Muni National Short category. BlackRock Short Duration Muni Inv A1 has an expense ratio of 0.47%, which is 19% lower than its category average, making the fund expense ratio grade a C. While it is difficult to predict returns, it is known that high annual expense ratios reduce your rate of return, and excessive fees are difficult to overcome. Active management normally comes with higher expense ratios than passive index management. Certain investment categories such as small company and foreign also normally have higher expense ratios. It is best to compare fund expense ratios against the category averages for meaningful assessments.
High portfolio turnover can translate to higher expenses and lower aftertax returns. BlackRock Short Duration Muni Inv A1 has a portfolio turnover rate of 66%, indicating that holds its assets around 0.0 years. By way of comparison, the average portfolio turnover is 51% for the Muni National Short category.
Recently, in the month of June 2026, BlackRock Short Duration Muni Inv A1 returned 0.5%, which earned it a grade of A, as the Muni National Short category had an average return of 0.3%. The letter grades of A, B, C, D and F are based upon relative rankings within the investment category. A grade of A, for example, would indicate that the return is in the highest 20% for that time period compared to all funds in that category.
BlackRock Short Duration Muni Inv A1 has a trailing yield of 3.37%, which is above the 2.77% category average. The fund normally distributes its income monthly and its capital gains annually.
It’s natural to seek the best-performing investments, but you must consider the relationship between risk and return and the impact of costs and taxes on your realized returns.
BlackRock Short Duration Muni Inv A1 Grades
Year to date, the fund has returned 1.4%, 0.1 percentage points better than the category, which translates into a grade of B. The fund has returned 4.3% over the past year (grade of A), 4.1% over the past three years (grade of A) and 2.1% per year over the past five years (grade of B) and 1.5% per year over the past 10 years (grade of D).
For more mutual fund grades, analysis and screening tools to help your investment discovery, join AAII for a $2, full-access trial. Learn more here: https://invest.aaii.com/membership.
Otherwise, for more information about BlackRock Short Duration Muni Inv A1, including its riskiness, submit your email to unlock the rest of the article.
Gain access to exclusive AAII member-only content.
MDLMX Trailing NAV Total Returns Data as of 6/30/26
| Last Month |
Last Quarter |
Ann'l. 1Yr |
Ann'l. 3Yr |
Ann'l. 5Yr |
Ann'l. 10Yr |
|
| MDLMX Return (NAV) | 0.5% | 1.4% | 4.3% | 4.1% | 2.1% | 1.5% |
| MDLMX Grade | A | A | A | A | B | D |
| +/- Category | 0.2% | 0.4% | 0.7% | 0.6% | 0.5% | -0.1% |
| Muni National Short Avg | 0.3% | 1.0% | 3.6% | 3.5% | 1.6% | 1.6% |
| MDLMX Tax Cost Ratio | na | na | 0.0% | 0.0% | 0.0% | 0.0% |
MDLMX Annual NAV Total ReturnsData as of 6/30/26
| 2026 | 2025 | 2024 | 2023 | 2022 | 2021 | 2020 | 2019 | 2018 | 2017 | 2016 | |
| MDLMX Return (NAV) | 1.4% | 5.0% | 2.9% | 4.4% | -2.7% | -0.1% | 1.2% | 2.4% | 1.3% | 0.9% | -0.2% |
| MDLMX Grade | B | A | B | A | B | D | F | D | B | F | C |
| +/- Category | 0.1% | 1.0% | 0.3% | 0.5% | 0.5% | -0.5% | -1.3% | -1.0% | 0.2% | -1.0% | -0.0% |
| Muni National Short Avg | 1.3% | 4.0% | 2.6% | 3.9% | -3.2% | 0.4% | 2.4% | 3.4% | 1.2% | 1.9% | -0.1% |
| Risk Measures | |
| Standard Deviation: | 2.1% |
| Total Risk Index: | 0.17 - Low |
| Category Risk Index: | 1.04 - Average |
| Category Risk Grade: | C (53% Rank) |
| Beta: | 0.35 |
| R-Squared: | 85% |
| Leveraged Fund: | No |
| Inverse Fund: | No |
| Portfolio Characteristics | |
| Equity Investment Style: | na |
| Bond Investment Style: | na |
| Yield: | 3.4% |
| Dividend Distribution: | Monthly |
| Cap Gains Distribution: | Annually |
| Total Assets: | $504 Mil |
| Fund Total Assets: | $ 7 Mil |
| Share Class Type: | A |
| Portfolio Turnover: | 66% |
Management Team
| Number of Managers: 4 | |||
| Longest Tenure: 6.8 years | |||
| Average Tenure: 4.0 years | |||
| Managers (Year): Manidis Kristi (2019), Romaglino Christian (2021), Maloney Kevin (2024), De Lorenzo Alicia (2024) | |||
Portfolio Composition (as of 5/31/26)
| # of Holdings: | 223 |
| % in Top 10 Holdings: | 18.8% |
| Fund is Non-Diversified: | No |
| % in Foreign Issues: | 0.0% |
Portfolio Allocation |
|
| Domestic Stock: | 0.0% |
| Foreign Stock: | 0.0% |
| Preferred Stock: | 0.0% |
| Domestic Bond: | 95.8% |
| Foreign Bond: | 0.0% |
| Convertible Bond: | 0.0% |
| Other: | 0.0% |
| Cash: | 4.2% |
Purchase Information
| Fund Family: | BlackRock |
| Phone Number: | 800-441-7762 |
| Website: | www.blackrock.com |
| Status: | Open |
| Inception Date: | October 21, 1994 |
| Min. Initial Purchase: | $ 0 |
| Min. Initial IRA Purchase: | $ 0 |
| True No-Load: | Yes |
| Front Load Maximum: | 0.00% |
| Deferred Charge Maximum: | 0.00% |
| Redemption Charge Maximum: | 0.00% |
| 12b-1 Fee: | 0.10% |
Expenses and Fees | |
| Expense Ratio (%): | 0.47% ( Rating : Avg ) |
| Category Average Expense Ratio (%): | 0.58% |
| Share Class: | BlackRock Short Duration Muni Instl |
| Min. Subsequent Purchase: | $ 0 |
| Min. Subsequent IRA Purchase: | $ 0 |
