AMUN vs SUB

AMUNBabrdn Ultra Short Municipal Income Active ETF

SUBAiShares Short-Term National Muni Bond ETF

In short

AMUN Ultra-short munis run by an active desk instead of an index, under a strategy whose track record dates to 1986. The aim: high after-tax income with capital preservation, paid out monthly.

SUB Munis, but only the near end of the curve. Since 2008 SUB has tracked an AMT-free index of investment-grade municipal bonds maturing inside five years, paying tax-exempt income monthly with far less rate sensitivity than long-dated muni funds.

Stated mandate

AMUN The fund seeks high after-tax current income while preserving capital.

SUB The fund seeks to track an index of short-term, investment-grade U.S. municipal bonds maturing from one month through five years, providing tax-exempt income while managing interest-rate risk.

Why people hold it

• AMUN A human desk picks the bonds and sets duration here, rather than mirroring a muni index. The stated job: high after-tax current income while preserving capital.
• 0.25% net of a waiver running through February 28, 2028, versus a 0.74% gross fee, and near what short-muni funds typically charge.
• Income lands monthly, and the portfolio stays inside its lane: US municipal bonds at the ultra-short end of the curve.

• SUB Charges 0.07% a year against a category median near 0.30%. On tax-exempt bond income, that fee gap is a meaningful slice of what actually reaches you.
• Two dials set on purpose: maturities from one month to five years, and an AMT-free index, so neither rate swings nor the alternative minimum tax hit the same way.ishares.com
• A multi-billion-dollar fund running since 2008 under iShares, with tight tracking of its ICE benchmark. One of the sturdier implementations in the muni group.
• Pays monthly, so the tax-exempt income arrives on a regular cadence rather than in quarterly lumps.

Worth knowing

• AMUN Cheaper index options sit on the same shelf, like VTES at 0.05% and SUB at 0.07%. Active management is what the extra cost buys.
• Thinly traded and small by category standards, so limit orders matter and spreads can be wider than at the big index funds.
• Capital preservation is the goal, not a promise: muni credit and rate moves still move the price, and the waiver is scheduled to end.

• SUB The five-year ceiling is the whole design, and it cuts both ways: less rate sensitivity, but a shorter stretch of the curve to draw income from than full-maturity muni funds.
• This is a national portfolio. Single-state funds like NYF chase a home-state tax break that a nationwide muni basket cannot offer.
• Broad-maturity peers VTEB and SCMB run at 0.03%. The short-end tilt here costs a few basis points more.

Full AMUN profile⁠

Full SUB profile⁠