485BPOS: Thornburg readies Premium Income Builder ETF (THOR)

The news: Thornburg ETF Trust filed a 485BPOS on May 22, 2026, Post-Effective Amendment No. 3 to its registration statement, registering the Thornburg Premium Income Builder ETF as a new series. The fund is set to trade on NYSE Arca under the ticker THOR. The fund seeks total return made up of income and, secondarily, capital appreciation. It invests in dividend-paying equities, including common and preferred stocks, depositary receipts and publicly traded REITs, along with other income-producing instruments. It adds an options strategy that uses covered calls and put options to generate premiums. The prospectus also permits debt obligations of any credit quality, equity-linked notes of up to 20% of assets, and business development companies.

By the numbers:

• Management fee: 0.79%.
• Estimated total annual expense ratio: 0.79% for the first full fiscal year.
• Equity-linked notes: up to 20% of assets.
• Portfolio managers: Matt Burdett and Brian J. McMahon of Thornburg Investment Management, Inc.

Why it matters: A 485BPOS is the filing that makes a registration effective, so this marks the point at which the fund is cleared to begin offering shares rather than a preliminary proposal. The strategy is broader than a typical single-index covered call fund. It combines dividend stocks, preferreds, REITs, credit and options, which gives the managers several ways to produce income, along with several sources of risk. Credit of any quality, equity-linked notes and BDCs each carry their own risks, from default to issuer counterparty exposure, so the fund’s results will depend heavily on how the managers size those sleeves. Options overlays can also limit participation in strong equity rallies, which is the usual cost of collecting premium.

The big picture: Income-oriented ETFs that use options have been a steady source of new ETF launches, and established active managers have continued to bring multi-asset income approaches into the ETF wrapper. Thornburg’s filing fits that pattern, packaging an active, flexible income mandate as an exchange-traded fund.

What’s next: Watch for the fund’s first trading day on NYSE Arca, its initial distribution rate, and how its asset mix evolves across equities, credit and equity-linked notes. Fund flows into the product will show whether the brand and the multi-asset approach can stand out in a crowded income category. Subsequent shareholder reports will show how much of its income comes from dividends versus option premiums.