Tax-Loss Selling Shifts Billions Into Muni ETFs, Squeezing Open-End Funds

What happened to muni funds this year

Vanguard points to tax-loss harvesting - selling losers to offset gains elsewhere - as a key driver pushing money toward municipal-bond ETFs in 2026 and away from open-end muni mutual funds. By Bloomberg's count, the third quarter added $23 billion to muni ETFs, while open-end muni mutual funds had $5.3 billion in net outflows.

The market's backdrop was rough. During the third quarter, municipals fell about 6.4% - the steepest quarterly drop in more than 40 years - as rising Treasury yields coincided with an influx of new issuance, seasonal reinvestment that was soft, and widespread tax-driven selling. The Bloomberg Municipal Bond Index hit a 14-month low on Sept. 29, then delivered almost a 6% return from that date.

JPMorgan says selling for tax reasons did not stop when prices bounced. October produced a 3.85% gain for munis, yet muni ETFs still posted their biggest inflow month on record at $20.8 billion, while open-end counterparts had $20.5 billion in outflows, the worst since April 2022, per a Nov. 9 note that cited LSEG Lipper.

Why money moved and who benefited

Tax rules matter here. To harvest losses and still maintain exposure, investors are required to switch for 30 days into a similar investment that is not substantially identical. That makes ETFs an easy pivot from open-end funds.

Vanguard's Justin Schwartz, head of municipals, thinks much of that money is likely to stick. "Are you going to take a gain to get back into the open-end fund?" he said. "Some of it will find its way back, but there's a good chance that a lot of it stays in the ETFs at this point."

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Flows show where investors landed. BlackRock's iShares National Muni Bond ETF has taken in $14 billion this year, and Vanguard's Tax-Exempt Bond ETF has gathered $12 billion, per Bloomberg data. Both funds follow broad municipal bond indexes.

Across the muni ETF universe, roughly 70% of about $266 billion in assets sit in passive products. Zooming out, JPMorgan says ETFs capture 97% of the $76 billion that has gone into muni funds this year.

The model portfolio tailwind

There is also a structural boost. Matthew Gastall, who heads Bloomberg Intelligence's muni-focused research and strategic work, points to broader use of model portfolios by advisers and clients as another engine for ETF demand.

These models, typically assembled through investment platforms, bundle ETFs and other vehicles into asset mixes that serve specific goals. Within them, positions can be adjusted to match an investor's risk tolerance, market view and planning needs.

What this means for your portfolio

In plain English: the tax rule's 30-day constraint and the convenience of ETFs are pulling muni money toward indexed, tradable wrappers, and some of those assets may not boomerang back to open-end funds even after the market's rebound. For muni exposure, that means bigger, more liquid ETFs are gaining share, while mutual funds face persistent outflows.

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