CATF vs MUB

CATFBAmerican Century California Municipal Bond ETF

MUBAiShares National Muni Bond ETF

In short

CATF A California-only muni portfolio that is actively run, not index-tracked: roughly 400 investment-grade bonds picked for income exempt from federal and California income taxes, at 0.25% with no fee waiver involved.

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

CATF The fund seeks high current income exempt from federal and California income taxes. It primarily invests in investment-grade bonds exempt from those taxes, using top-down credit and duration analysis plus research-driven security selection.

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

• CATF Income aims to dodge two tax bills, not one: the portfolio sits in investment-grade bonds exempt from both federal and California income taxes, and it pays out monthly.americancentury.com
• Human judgment, not a rulebook: top-down credit and duration calls plus bond-by-bond research including nonrated names, with the S&P California AMT-Free index as the yardstick.americancentury.com
• 0.25% with no fee waiver sits near the muni category median and close to index-tracker TFI at 0.23%, a tight price for active, single-state management.
• Sits in the upper half of a crowded muni ETF field, and what it holds matches what it promises: California paper, investment grade, income first.

• 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

• CATF Thinly traded and still a modest-sized fund, so bid-ask spreads can run wider than the category's national giants and larger orders need more care.
• One state, one budget. All-California issuers means the portfolio rides California's economy, and the state exemption only counts if you pay California income tax.
• Launched in 2024, so the track record is short next to muni funds with decades of rate cycles behind them.

• 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 CATF profile⁠

Full MUB profile⁠