MUB vs TAXM

MUBAiShares National Muni Bond ETF

TAXMCBondBloxx IR+M Tax-Aware ETF for Massachusetts Residents

In short

MUB Municipal bonds, indexed and cheap. Since 2007, MUB has packaged investment-grade national munis into tax-exempt monthly income for five basis points a year, and it sits among the deepest pools in the muni-ETF aisle.

TAXM Single-state muni investing, ETF-style: IR+M actively picks short-duration municipal and taxable bonds screened for after-tax income for Massachusetts residents. Narrow by design, and young (launched 2025).

Stated mandate

MUB The fund seeks to track an index of investment-grade U.S. municipal bonds, providing diversified exposure to the national municipal-bond market and tax-exempt income.

TAXM The Fund seeks attractive after-tax income while preserving capital. It actively manages a diversified portfolio of U.S.-dollar municipal and taxable short-duration fixed-income securities selected for relatively attractive after-tax income for Massachusetts residents.

Why people hold it

• MUB 0.05% a year against a muni-ETF median near 0.30%. In a category built on modest, tax-exempt yields, that fee gap is real money left in the fund.
• The benchmark is AMT-free: the ICE AMT-Free US National Municipal Index screens out munis whose interest can be pulled into the alternative minimum tax.ishares.com
• Tracks its index closely, one of the tighter jobs in its peer group, and distributes monthly. A multi-billion-dollar fund that trades actively.
• Broad investment-grade exposure across the national muni market, spread over thousands of issuers rather than one state's budget.ishares.com

• TAXM A rare state-level mandate in an ETF: the portfolio targets after-tax income specifically for Massachusetts residents, not the national muni average.
• Active, not index-bound. IR+M builds a diversified mix of muni and taxable short-duration bonds, with capital preservation named alongside income in the objective.
• Holdings line up closely with the stated mandate, one of the tighter mandate-to-portfolio matches among muni funds.
• Pays monthly, the usual cadence income-focused bond investors look for.

Worth knowing

• MUB Two rivals undercut it: VTEB and SCMB both run 0.03%. A two-basis-point gap is small, but it is a gap.
• A bond fund with no maturity date to hold to. Share prices move with interest rates and muni credit conditions, both directions.
• National by design, so no single-state tilt and no in-state tax angle. iShares runs state-specific muni funds such as NYF for that job.

• TAXM At 0.35%, it costs more than its muni peer group's typical fee and far more than broad index munis like VTEB (0.03%) or MUB (0.05%).
• Small and thinly traded, so spreads can run wider than in mainstream muni ETFs.
• Launched in 2025, so the track record is short and the state-specific focus is narrower than a national muni portfolio.

Full MUB profile⁠

Full TAXM profile⁠