HYMB vs THYM

HYMBAState Street SPDR Nuveen ICE High Yield Municipal Bond ETF

THYMBT. Rowe Price High Income Municipal ETF

In short

HYMB Most muni index funds stop at investment grade. HYMB keeps going: its benchmark reaches from A-rated paper down through unrated deals, spreading roughly 1,900 tax-exempt bonds across that credit line. Income lands monthly.

THYM The credit-risk end of T. Rowe Price's muni lineup: an active ETF chasing federally tax-exempt income in longer-term, low- to upper-medium quality bonds, terrain its muni desk has worked since 1985.

Stated mandate

HYMB The fund seeks to track, before fees and expenses, the price and yield performance of the ICE US Select High Yield Crossover Municipal Index, which covers lower-rated and unrated tax-exempt municipal debt issued in the United States.

THYM The fund seeks a high level of income exempt from federal income taxes.

Why people hold it

• HYMB The crossover mandate is the whole point: the index covers lower-rated (A3/A+ or lower) and unrated tax-exempt debt, not another top-grade general-obligation ladder.ssga.com
• About 1,900 bonds dilute any single issuer's trouble, and State Street has run the fund since 2011, through more than one muni credit scare.
• One of the more actively traded funds in the muni ETF aisle, which counts in a market where the underlying bonds themselves can sit still for weeks. Pays monthly.

• THYM Active by design: T. Rowe's municipal team picks longer-term, lower-rated bonds one credit at a time, rather than tracking an index.troweprice.com
• The stated job is a high level of income exempt from federal income tax, with distributions declared monthly.
• Fee is 0.32%, close to what the typical muni ETF charges, for a strategy that leans on analysts instead of an index.troweprice.com
• It slots in as the credit sleeve of T. Rowe's muni ETF shelf, which already spans short, intermediate and long investment-grade maturities.troweprice.com

Worth knowing

• HYMB 0.35% a year is the toll for assembling illiquid paper. Broad, plain-vanilla muni index funds such as VTEB and SCMB charge 0.03%.
• Lower-rated and unrated munis carry default and downgrade risk that top-rated general-obligation bonds don't, and prices can move sharply when muni buyers step back.
• The benchmark has been swapped before (Bloomberg to ICE in 2025), so older track records reflect a different index than the one the fund follows now.ssga.com

• THYM Index heavyweights are far cheaper: VTEB runs 0.03% and MUB 0.05%. Here the fee buys credit research, not broad market exposure.
• Low- to upper-medium quality munis bring real default and liquidity risk, and longer maturities swing more when rates move.troweprice.com
• A November 2025 launch, small and thinly traded so far, which can mean wider bid-ask spreads than the long-established index munis.

Full HYMB profile⁠

Full THYM profile⁠