BKMS vs SUB

BKMSCBNY Mellon Municipal Short Duration ETF

SUBAiShares Short-Term National Muni Bond ETF

In short

BKMS A short-duration municipal bond portfolio with a track record that starts in 2000, now in an ETF wrapper. The idea: federally tax-exempt income from a couple hundred bonds, with maturities kept close in rather than stretched out.

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

BKMS The fund seeks to maximize current income exempt from federal income tax while preserving capital. It normally invests at least 80% of assets, plus investment borrowings, in tax-exempt municipal bonds.

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

• BKMS The mandate is written down: at least 80% of assets in tax-exempt municipal bonds, aiming to maximize income exempt from federal income tax while preserving capital.
• Short duration is the design choice. Keeping maturities close in mechanically dampens how much the portfolio's price moves when rates do, compared with long-dated muni funds.
• The strategy dates to 2000, so it has run through multiple rate cycles rather than one.
• Spread across roughly a couple hundred municipal bonds, so no single issuer carries the portfolio.

• 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

• BKMS At 0.35%, the fee sits above the muni cohort median. Index heavyweights set a low bar here: VTEB at 0.03% and MUB at 0.05%.
• Thinly traded next to the big muni ETFs, so the spread you cross on the way in and out can matter as much as the headline fee.
• Distributions arrive on an irregular schedule rather than a fixed monthly one, which is worth knowing if you plan around income timing.

• 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 BKMS profile⁠

Full SUB profile⁠