Fund Evaluator:
iShares Municipal Bond Index Investor A (BIDAX)
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Best Performing in Muni National Long Over the Last Year
| 7.5% | Victory Tax Exempt Long-Term (USTEX) |
| 7.3% | Vanguard High-Yield Tax-Exempt Adm (VWALX) |
| 7.2% | Vanguard High-Yield Tax-Exempt (VWAHX) |
| 7.1% | Thrivent Municipal Bond S (TMBIX) |
| 7.0% | T. Rowe Price Core Municipal Bond (PRTAX) |
Fund Details
iShares Municipal Bond Index Investor A Overview
iShares Municipal Bond Index Investor A (BIDAX) is a passively managed Municipal Bond Muni National Long fund. BlackRock launched the fund in 2000.
The investment seeks to provide investment results that correspond to the total return performance of fixed-income securities in the aggregate, as represented by the ICE BofA U.S. Municipal Securities Index. The fund generally invests at least 80% of its assets, plus the amount of any borrowings for investment purposes, in securities or other financial instruments that are components of or have economic characteristics similar to the securities in the index. The index tracks the performance of U.S. dollar denominated investment grade tax-exempt debt publicly issued by U.S. states and territories, and their political subdivisions, in the U.S. domestic market.
About iShares Municipal Bond Index Investor A (BIDAX)
There are 3 members of the management team with an average tenure of 3.39 years: James Mauro (2018), Jonathan Graves (2025), Marcus Tom (2025). Management tenure is more important for actively managed funds than passive index funds.
The fund has 1 primary benchmark: ICE BofA US Muni TR USD index with a weighting of 100%. iShares Municipal Bond Index Investor A has 417 securities in its portfolio. The top 10 holdings constitute 7.9% 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.
iShares Municipal Bond Index Investor A is part of the Fixed Income global asset class and is within the Municipal Bond fund group. iShares Municipal Bond Index Investor A 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 100.6% (100.6% domestic bond, 0.0% foreign bond and 0.0% convertible bond). iShares Municipal Bond Index Investor A has -0.6% of the portfolio in cash.
Assets Under Management
The fund has $16 million in total assets, which is below the $1 billion average for the Muni National Long 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.
BIDAX 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 iShares Municipal Bond Index Investor A expense ratio is average compared to funds in the Muni National Long category. iShares Municipal Bond Index Investor A has an expense ratio of 0.50%, which is 36% lower than its category average, making the fund expense ratio grade a B. 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. iShares Municipal Bond Index Investor A has a portfolio turnover rate of 38%, indicating that holds its assets around 0.0 years. By way of comparison, the average portfolio turnover is 38% for the Muni National Long category.
Recently, in the month of July 2026, iShares Municipal Bond Index Investor A returned -1.8%, which earned it a grade of C, as the Muni National Long category had an average return of -1.9%. 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.
iShares Municipal Bond Index Investor A has a trailing yield of 3.18%, which is below the 3.72% category average. The fund normally distributes its income monthly.
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.
iShares Municipal Bond Index Investor A Grades
Year to date, the fund has returned 0.2%, 0.7 percentage points worse than the category, which translates into a grade of F. The fund has returned 4.9% over the past year (grade of F), 2.6% over the past three years (grade of F) and 0.2% per year over the past five years (grade of C) and 1.6% per year over the past 10 years (grade of D).
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BIDAX Trailing NAV Total Returns Data as of 7/31/26
| Last Month |
Last Quarter |
Ann'l. 1Yr |
Ann'l. 3Yr |
Ann'l. 5Yr |
Ann'l. 10Yr |
|
| BIDAX Return (NAV) | -1.8% | -0.6% | 4.9% | 2.6% | 0.2% | 1.6% |
| BIDAX Grade | C | F | F | F | C | D |
| +/- Category | 0.0% | -0.3% | -1.4% | -0.6% | 0.2% | -0.1% |
| Muni National Long Avg | -1.9% | -0.3% | 6.3% | 3.2% | 0.0% | 1.8% |
| BIDAX Tax Cost Ratio | na | na | 0.0% | 0.0% | 0.0% | 0.1% |
BIDAX Annual NAV Total ReturnsData as of 7/31/26
| 2026 | 2025 | 2024 | 2023 | 2022 | 2021 | 2020 | 2019 | 2018 | 2017 | 2016 | |
| BIDAX Return (NAV) | 0.2% | 3.4% | 0.9% | 6.2% | -8.8% | 1.4% | 4.7% | 7.2% | 1.2% | 3.8% | 0.5% |
| BIDAX Grade | F | B | F | D | A | F | C | D | B | F | B |
| +/- Category | -0.7% | 0.4% | -1.5% | -0.6% | 2.8% | -1.5% | -0.0% | -0.8% | 0.5% | -2.0% | 0.3% |
| Muni National Long Avg | 0.9% | 3.0% | 2.5% | 6.8% | -11.6% | 2.8% | 4.7% | 8.1% | 0.7% | 5.8% | 0.2% |
| Risk Measures | |
| Standard Deviation: | 5.8% |
| Total Risk Index: | 0.47 - Below Average |
| Category Risk Index: | 0.89 - Below Average |
| Category Risk Grade: | B (23% Rank) |
| Beta: | 1.01 |
| R-Squared: | 99% |
| Leveraged Fund: | No |
| Inverse Fund: | No |
| Portfolio Characteristics | |
| Equity Investment Style: | na |
| Bond Investment Style: | High Quality Moderate Sensitivity |
| Yield: | 3.2% |
| Dividend Distribution: | Monthly |
| Cap Gains Distribution: | None |
| Total Assets: | $198 Mil |
| Fund Total Assets: | $ 17 Mil |
| Share Class Type: | A |
| Portfolio Turnover: | 38% |
Management Team
| Number of Managers: 3 | |||
| Longest Tenure: 8.2 years | |||
| Average Tenure: 3.4 years | |||
| Managers (Year): Mauro James (2018), Graves Jonathan (2025), Tom Marcus (2025) | |||
Portfolio Composition (as of 6/30/26)
| # of Holdings: | 417 |
| % in Top 10 Holdings: | 7.9% |
| 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: | 100.6% |
| Foreign Bond: | 0.0% |
| Convertible Bond: | 0.0% |
| Other: | 0.0% |
| Cash: | -0.6% |
Purchase Information
| Fund Family: | BlackRock |
| Phone Number: | 800-447-7762 |
| Website: | www.blackrock.com |
| Status: | Closed |
| Inception Date: | December 18, 2000 |
| Min. Initial Purchase: | $1,000 |
| 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: | 0.25% |
Expenses and Fees | |
| Expense Ratio (%): | 0.50% ( Rating : Avg ) |
| Category Average Expense Ratio (%): | 0.78% |
| Share Class: | iShares Municipal Bond Index Investor A |
| Min. Subsequent Purchase: | $ 50 |
| Min. Subsequent IRA Purchase: | $ 0 |
