DFNM vs MUB

DFNMADimensional National Municipal Bond ETF

MUBAiShares National Muni Bond ETF

In short

DFNM Active muni management on a short leash. Dimensional leans longer on the curve when longer bonds pay for the risk, but keeps duration inside a band anchored to an intermediate AMT-free muni index.

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.

Stated mandate

DFNM The fund seeks current income expected to be exempt from federal income tax.

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.

Why people hold it

• DFNM The mechanism: when the expected term premium favors longer maturities it focuses there, otherwise shorter, all inside a documented duration band around its benchmark.sec.gov
• 0.17% net (0.18% gross, net of a waiver through February 28, 2027) sits below the muni category median fee, which is unusual for a fund with a manager making calls.
• Roughly 1,000 bonds, investment grade at purchase, with no stated intent to hold munis whose interest is subject to the federal AMT. Income pays monthly.sec.gov

• 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

Worth knowing

• DFNM Index rivals charge less: VTEB and SCMB 0.03%, MUB 0.05%. The systematic curve and credit work is what the extra cost buys.
• Intermediate rate risk is baked in. The band allows duration a half year above or a full year below the benchmark's, so prices move when yields do.sec.gov
• Federal exemption is the target, not state. Dimensional houses state-level breaks in separate funds, such as its California muni ETF.sec.gov

• 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.

Full DFNM profile⁠

Full MUB profile⁠