FLMB vs MUB

FLMBBFranklin Municipal Green Bond ETF

MUBAiShares National Muni Bond ETF

In short

FLMB Most muni funds buy the whole tax-exempt market. FLMB narrows the lens: a prospectus commitment of at least 80% of net assets to municipal green bonds, held in a compact portfolio that pays income monthly.

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

FLMB The fund commits at least 80% of its net assets to municipal green bonds.

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

• FLMB The green mandate is contractual, not marketing: the prospectus commits at least 80% of net assets to municipal green bonds.
• Compact by design, roughly 80 bonds, so the green-project theme shows up in the portfolio instead of being diluted across thousands of holdings.
• The screen doesn't cost extra versus the typical muni fund: 0.30%, right at the category median.
• Municipal bond income, paid monthly, from a Franklin Templeton fund that has been trading since 2017.

• 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

• FLMB Thinly traded. The bid-ask spread can matter more to your all-in cost than the expense ratio does.
• The broad muni index giants run far cheaper: VTEB and SCMB at 0.03%, MUB at 0.05%. The green screen carries a real price premium.
• A slice of a slice. With about 80 bonds, individual issuers and project types swing results more than in a thousand-bond index fund.

• 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 FLMB profile⁠

Full MUB profile⁠