BlackRock High Yield Muni Income Bond ETF (HYMU) is an actively managed exchange-traded fund that seeks to maximize current tax-exempt income and secondarily capital appreciation through investments in high yield and other income generating U.S. municipal bonds, primarily those rated BBB or below by S&P or Fitch and Baa or below by Moody's, with maturities generally of five years or longer; the fund benchmarks performance against a custom blend comprising 80% Bloomberg Municipal High Yield Index, 10% Bloomberg BBB Index, and 10% Bloomberg Single A Index. HYMU holds a diversified portfolio of approximately 365 municipal bonds issued by state and local governments, transportation authorities, energy cooperatives, universities, and other public finance entities, with top holdings including Public Finance Authority Wisconsin, New York Transportation Development Corp, Black Belt Energy Gas District, and Southeast Energy Authority; at least 80% of assets are invested in such municipal securities, including up to 10% in distressed or unrated bonds, managed by BlackRock's Municipal Bond Team using proprietary credit analysis, duration modeling, and sector allocation. Launched on March 16, 2021, and domiciled in the United States under BlackRock ETF Trust II, the fund operates with a net expense ratio of 0.35%, manages approximately $286 million in assets, and trades on BATS with a trailing 12-month yield around 4.4%. In recent developments, HYMU has maintained stable operations amid market volatility, with no major acquisitions, partnerships, or strategic shifts specific to the fund reported in 2024 or 2025; however, BlackRock expanded its high yield municipal offerings in February 2025 by converting the BlackRock High Yield Municipal Fund into the related iShares High Yield Muni Active ETF (HIMU), enhancing the firm's active muni bond ETF suite backed by its $182 billion Municipal Bond Group. The ETF targets income-seeking investors, including individuals and institutions pursuing tax-advantaged fixed income exposure across U.S. regions without international operations.