# EDGAR Filing Document

**Accession Number:** 0002038383
**File Stem:** 0001999371-26-011723
**Filing Date:** 2026-6
**Character Count:** 39981
**Document Hash:** 32412de71136312ad0941e06479cda2e
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001999371-26-011723.hdr.sgml**: 20260601

**ACCESSION NUMBER**: 0001999371-26-011723

**CONFORMED SUBMISSION TYPE**: 497K

**PUBLIC DOCUMENT COUNT**: 2

**FILED AS OF DATE**: 20260601

**DATE AS OF CHANGE**: 20260601

**EFFECTIVENESS DATE**: 20260601

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Thornburg ETF Trust
- **CENTRAL INDEX KEY:** 0002038383

**ORGANIZATION NAME:**
- **EIN:** 000000000
- **STATE OF INCORPORATION:** MA

**FILING VALUES:**
- **FORM TYPE:** 497K
- **SEC ACT:** 1933 Act
- **SEC FILE NUMBER:** 333-282372
- **FILM NUMBER:** 261047283

**BUSINESS ADDRESS:**
- **STREET 1:** 2300 NORTH RIDGETOP ROAD
- **CITY:** SANTA FE
- **STATE:** NM
- **ZIP:** 87506
- **BUSINESS PHONE:** 617-235-4739

**MAIL ADDRESS:**
- **STREET 1:** 2300 NORTH RIDGETOP ROAD
- **CITY:** SANTA FE
- **STATE:** NM
- **ZIP:** 87506

## Series and Classes Contracts Data

### Thornburg Premium Income Builder ETF (Series ID: S000105007)

| Class ID   | Class Name                           | Ticker Symbol   |
|:---|:---|:---|
| C000275711 | Thornburg Premium Income Builder ETF | THOR            |

For the Fund's **Prospectus** or **SAI**, visit www.thornburg.com/download

![](thor-497k_052626img001.gif)

## Thornburg Premium Income Builder ETF Summary Prospectus

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| | |
|:---|:---|
| &nbsp;&nbsp; **May 26, 2026** | &nbsp;&nbsp; **Ticker Symbol:** THOR |

---

*Before you invest, you may want to review the Fund's Prospectus and Statement of Additional Information (SAI), which contain more information about the Fund and its risks. You can find the Fund's Prospectus, SAI and other information about the Fund online at www.thornburg.com/download. You can also get this information at no cost by calling 800.847.0200 or by sending an e-mail request to info@thornburg.com. The current Prospectus and SAI, dated May 26, 2026, as may be amended or supplemented from time to time, are incorporated by reference into this Summary Prospectus.* 

**Investment Objective**

The Thornburg Premium Income Builder ETF (the "Fund") seeks total return consisting of income and, secondarily, capital appreciation. The Fund's investment objectives may be changed without shareholder approval.

**Fees and Expenses**

This table describes the fees and expenses you may pay if you buy, hold and sell shares of the Fund. **You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and** **Example below.**

Annual Fund Operating Expenses

(expenses that you pay each year as a percentage of the value of your investment)

---

| | |
|:---|:---|
| &nbsp;&nbsp; Management Fees | &nbsp;&nbsp; 0.79% |
| &nbsp;&nbsp; Other Expenses\* | &nbsp;&nbsp; 0.00% |
| &nbsp;&nbsp; Total Annual Fund Operating Expenses | &nbsp;&nbsp; 0.79% |

---

\*"Other Expenses" is an estimate based on the expenses the Fund expects to incur for its first full fiscal year.

**Example.** This example is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds.

The example assumes that you invest $10,000 in the Fund for the time periods indicated (whether or not shares are sold or redeemed), that your investment has a 5% return each year and that the Fund's operating expenses remain the same. The example does not take into account brokerage commissions and other fees to financial intermediaries that you may pay on your purchases and sales of shares of the Fund. It also does not include the transaction fees on purchases and redemptions of creation units ("Creation Units"), because those fees will not be imposed on retail investors. Although your actual costs may be higher or lower, based on these assumptions, your costs would, based on estimated Fund expenses, be:

---

| | |
|:---|:---|
| &nbsp;&nbsp; **1 Year** | &nbsp;&nbsp; **3 Years** |
| &nbsp;&nbsp; $81 | &nbsp;&nbsp; $252 |

---

**Portfolio Turnover.** The Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example above, affect the Fund's performance. Because the Fund had not commenced operations prior to the date of this prospectus, the Fund's portfolio turnover rate for the most recent fiscal year end is not yet available.

**Principal Investment Strategies**

The Fund pursues its investment goals by investing in a broad range of dividend paying equity securities, including, but not limited to, common stocks, preferred stocks, depositary receipts and publicly traded real estate investment trusts ("REITs"); and in income producing instruments of any kind. The Fund may invest in any stock or other equity security which its investment adviser, Thornburg Investment Management, Inc. ("Thornburg" or the "Adviser"), believes may assist the Fund in pursuing its investment goals. The Fund may invest in securities of companies of any market capitalization.

The Fund may invest a significant portion of its assets in securities of issuers domiciled in or economically tied to countries outside the United States, including developing market countries. The relative proportion of U.S. and non-U.S. securities held by the Fund may vary from time to time, depending upon Thornburg's view of specific investment opportunities and macro-economic factors.

The Fund will opportunistically utilize an "option strategy" consisting of writing (selling) covered call and put option contracts on individual securities, and writing (selling) call and put option contracts on broad-based U.S. and non-U.S. market indexes, in each case in order to generate additional income in the form of premiums on the options. A call option written (sold) by the Fund will give the holder (buyer) the right to buy a certain equity security at a predetermined strike price from the Fund. A put option written (sold) by the Fund will give the holder (buyer) the right to sell a certain equity security at a predetermined strike price to the Fund. A premium is the income received by the writer of the option contract.

The Fund's investments are determined by individual issuer and industry analysis. Investment decisions are based on domestic and international economic developments, outlooks for securities markets, interest rates and inflation, the supply and demand for securities, and analysis of specific issuers.

The Fund may sell an investment if Thornburg has identified a better investment opportunity, in response to changes in the conditions or business of the investment's issuer or changes in overall market conditions, if Thornburg has a target price for the investment and that target price has been achieved, or if, in Thornburg's opinion, the investment no longer serves to achieve the Fund's investment goals.

The Fund may, from time to time, invest opportunistically and without limit in debt obligations of any kind, including corporate bonds and other obligations, mortgage- and other asset-backed securities and government obligations. The Fund may purchase debt obligations of any maturity and

THORNBURG Premium Income Builder ETF **SUMMARY PROSPECTUS** May 26, 2026

**2**

For the Fund's **Prospectus** or **SAI**, visit www.thornburg.com/download

of any credit quality, including "high yield" or "junk" bonds. There is no minimum credit quality or rating of debt obligation the Fund may purchase. The Fund also may invest in debt obligations which have a combination of equity and debt characteristics, such as convertible bonds.

The Fund may enter into derivatives transactions and other instruments of any kind for hedging purposes or otherwise to gain, or reduce, long or short exposure to one or more asset classes or issuers.

The Fund may invest up to 20% of its net assets in equity-linked notes ("ELNs"). ELNs are structured as notes that are issued by counterparties, including banks, broker-dealers or their affiliates, and that are designed to offer a return linked to the underlying instruments within the ELN, which may include options. The options underlying the ELNs in which the Fund may invest may be based on a broad-based index, exchange-traded funds ("ETFs") or individual securities. The ELNs owned by the Fund are structured to use a covered call strategy and have short call positions embedded within them. When the Fund purchases the ELN from the issuing counterparty, the Fund is entitled to the premium generated by the short call position within the ELN. When the Fund sells call options within an ELN, it receives a premium but limits its opportunity to profit from an increase in the market value of either the underlying broad-based index, ETF or individual security name to the exercise price (plus the premium received). The maximum potential gain on an underlying instrument will be equal to the difference between the exercise price and the purchase price of the underlying broad-based index, ETF or individual security name at the time the option is written, plus the premium received.

Subject to applicable statutory and regulatory limitations, the Fund may also invest in securities issued by other investment companies, such as business development companies.

The Fund is classified as a non-diversified fund and may invest in a smaller number of issuers and have a greater percentage of its assets in those issuers than a diversified investment company.

**Principal Risks**

As with any investment, you could lose all or a substantial part of your investment in the Fund, and the Fund's performance could trail that of other investments. The Fund is subject to certain risks, including the principal risks noted below, any of which may adversely affect the Fund's net asset value per share ("NAV"), trading price, yield, total return and ability to meet its investment objective. Your investment in the Fund is not a deposit of any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

• <u><u>New and Smaller Sized Fund Risk</u></u>. The Fund is relatively new and has a limited operating history for investors to evaluate and may not be successful in implementing its investment strategies. The Fund may fail to attract sufficient assets to achieve or maintain economies of scale, which could result in the Fund being liquidated at any time without shareholder approval and at a time that may not be favorable for all shareholders. Smaller ETFs will have a lower public float and lower trading volumes, leading to wider bid/ask spreads.

• <u><u>Investment Adviser Risk</u></u>. The Fund is actively managed and the success of its investment strategy depends significantly on the skills of Thornburg in assessing the potential of the investments in which the Fund invests. This assessment of investments may prove incorrect, resulting in losses or poor performance, even in rising markets. There is also no guarantee that the Adviser will be able to effectively implement the Fund's investment objective.

• <u><u>ETF Structure Risks</u></u>. The Fund is structured as an ETF and is subject to risks related to exchange trading, including:

–The Fund's shares are listed for trading on the NYSE Arca, Inc. (the "Exchange") and are bought and sold on the secondary market at market prices. Although it is expected that the market price of Fund shares will typically approximate the Fund's NAV, there may be times when the market price reflects a significant premium or discount to NAV.

–Although the Fund's shares are listed on the Exchange, it is possible that an active trading market in the Fund's shares may not be maintained. In stressed market conditions, the market for the Fund's shares may become less liquid in response to deteriorating liquidity in the markets for the Fund's underlying portfolio holdings, which could lead to wider bid/ask spreads and differences in the market price of the Fund's shares and the underlying value of those shares.

–The Fund could potentially face trading halts and/or delisting from the Exchange. This risk is heightened in times of market stress, including at both the Fund share level and at the Fund holdings level.

–Only an authorized participant (an "Authorized Participant") may engage in creation or redemption transactions directly with the Fund, and none of those Authorized Participants is obligated to engage in creation and/or redemption transactions. The Fund has a limited number of institutions that may act as Authorized Participants on an agency basis (i.e., on behalf of other market participants). In addition, to the extent that securities held by the Fund are traded outside a collateralized settlement system, Authorized Participants may be required to post collateral on certain trades on an agency basis (on behalf of other market participants), which only a limited number of Authorized Participants may be able to do. To the extent that Authorized Participants exit the business or are unable to proceed with creation or redemption orders with respect to the Fund and no other Authorized Participant is able to step forward to create or redeem Creation Units, Fund shares may be more likely to trade at a premium or discount to NAV and possibly face trading halts or delisting.

• <u><u>Equity Risk</u></u>. The value of the Fund's equity investments may fluctuate significantly over time in response to factors affecting individual issuers, particular industries, or the market as a whole. Additionally, common stock ranks below preferred stock and debt securities in claims for dividends and for assets of a company in a liquidation or bankruptcy.

• <u><u>Options Strategy Risk</u></u>. The Fund's use of call and put options involves speculation and can lead to losses because of adverse movements in the price or value of the underlying stock, index, or other asset, which may be magnified by certain features of the options. The Fund's successful use of options depends on the ability of the Adviser to forecast market movements correctly. For example, if the Fund were to write (sell) a call option on an index or security based on the Adviser's expectation that the price of an index or security would fall, but the price were to rise instead, the Fund could be required to sell the underlying asset upon exercise at a price below the current market price. Alternatively, if the Fund were to write (sell) a put option on an index or security, the Fund assumes the risk of loss should the price of the underlying security decline below the exercise price of the put option. When selling a call or put option, the Fund will receive a premium; however, this premium may not be enough to offset a loss incurred by the Fund if the price of the underlying asset is, in the case of a call option, above or, in the case of a put option, below the strike price by an amount equal to or greater than the premium. As the writer of a call option, the Fund forgoes, during the option's life, the opportunity to profit from increases in the market value of the underlying security or instrument covering the option above the sum of the premium and the exercise price, but retains the risk of loss should the price of the underlying security or instrument decline. The value of an option may be adversely affected if the market for the option becomes less liquid or smaller, and will be affected by changes in the value or yield of the option's underlying asset, an increase in interest rates, a change in the actual or perceived volatility of the stock market or

**3**

**SUMMARY PROSPECTUS** MAY 26, 2026 THORNBURG Premium Income Builder ETF

For the Fund's **Prospectus** or **SAI**, visit www.thornburg.com/download

the underlying asset and the remaining time to expiration. Additionally, the value of an option does not increase or decrease at the same rate as the underlying asset(s). In addition, if the price of the underlying asset of an option is above the strike price of a written call, or below the strike price of a written put, the value of the option, and consequently of the Fund, may decline significantly more than if the Fund invested directly in the underlying asset instead of using options. The Fund could experience a loss if its options do not perform as anticipated, or are not correlated with the performance of their underlying asset or if the Fund is unable to purchase or liquidate a position because of an illiquid secondary market.

• <u><u>Foreign Investment Risk</u></u>. Investments in securities of foreign issuers may involve risks including adverse fluctuations in currency exchange rates, political instability, confiscations, taxes or restrictions on currency exchange, difficulty in selling foreign investments, and reduced legal protection. In addition, some foreign government debt obligations may be subject to default, delays in payment, adverse legislation or government action, or could be downgraded by ratings agencies.

• <u><u>Foreign Currency Risk</u></u>. Fluctuations in currency exchange rates can adversely affect the value of the Fund's foreign investments. Such fluctuations may occur for a number of reasons, including market and economic conditions, or a government's decision to devalue its currency or impose currency controls. Thornburg may seek to hedge foreign currency risks, but its hedging strategies may not be successful, or its judgments not to use hedging strategies may not correctly anticipate actual conditions and result in loss or higher costs to the Fund. Furthermore, any hedging strategy that Thornburg pursues, such as the use of currency forward contracts, may involve additional risks. Foreign investments, even if denominated in U.S. dollars, may be affected significantly by fluctuations in the value of foreign currencies, and the value of these securities in U.S. dollars may decline even if the securities increase in value in their home country.

• <u><u>Emerging Markets Risk</u></u>. The risks which may affect investments in foreign issuers may be more pronounced for investments in emerging markets, also known as developing countries, because the economies of those markets are usually less diversified; communications, transportation and economic infrastructures are less developed; and emerging markets ordinarily have less established legal, political, business and social frameworks. At times the prices of equity securities or debt obligations of an issuer in an emerging market may be extremely volatile. An issuer in a developed country may be similarly affected by these emerging markets risks to the extent that the issuer conducts its business in emerging markets.

• <u><u>Risks of Investing in Depositary Receipts</u></u>. An investment in American Depositary Receipts ("ADRs"), European Depositary Receipts ("EDRs") or Global Depositary Receipts ("GDRs") is an alternative to the purchase of the underlying securities in their national markets and/or currencies. However, ADRs, EDRs, and GDRs remain subject to many of the risks associated with investing directly in foreign securities, including the political and economic risks associated with the underlying issuer's country. Certain countries may limit the ability to convert a depositary receipt into the underlying foreign security and vice versa, which may cause the securities of the foreign company to trade at a discount or premium to the market price of the related depositary receipts. Moreover, EDRs and GDRs can involve currency risk since, unlike ADRs, they may not be U.S. dollar denominated.

• <u><u>Real Estate Risk</u></u>. The Fund's investments in publicly traded REITs are subject to risks affecting real estate investments generally (including market conditions, competition, property obsolescence, changes in interest rates and casualty to real estate), as well as risks specifically affecting REITs (the quality and skill of REIT management and the internal expenses of the REIT).

• <u><u>Derivatives Risk</u></u>. The Fund's investments in options and other derivative instruments involve the risks associated with the securities or other assets underlying those derivatives as well as risks different and/or greater than the risks affecting the underlying assets, including the inability or unwillingness of the other party to a derivative to perform its obligations to the Fund, the Fund's inability or delays in selling or closing positions in derivatives and difficulties in valuing derivatives.

• <u><u>Focused Investment Risk</u></u>. A fund that invests a substantial portion of its assets in a particular market, industry, sector, group of industries or sectors, country, region, group of countries, limited number of issuers or asset class is, relative to a fund that invests in a more diverse investment portfolio, more susceptible to any single economic, market, political, regulatory or other occurrence. This is because, for example, issuers in a particular market, industry, region, sector or asset class may react similarly to specific economic, market, regulatory, political or other developments. The particular markets, industries, regions, sectors or asset classes in which the Fund may focus its investments may change over time and the Fund may alter its focus at inopportune times.

• <u><u>Equity-Linked Notes Risk</u></u>. When the Fund invests in ELNs, it receives cash but limits its opportunity to profit from an increase in the market value of the instrument because of the limits relating to the call options written within the particular ELN. Investing in ELNs may be more costly to the Fund than if the Fund had invested in the underlying instruments directly. Investments in ELNs often have risks similar to the underlying instruments, which include market risk. In addition, since ELNs are in note form, ELNs are subject to certain debt securities risks, such as credit or counterparty risk. Should the prices of the underlying instruments move in an unexpected manner, the Fund may not achieve the anticipated benefits of an investment in an ELN, and may realize losses, which could be significant and could include the Fund's entire principal investment. Investments in ELNs are also subject to liquidity risk, which may make ELNs difficult to sell and value. A lack of liquidity may also cause the value of the ELN to decline. In addition, ELNs may exhibit price behavior that does not correlate with the underlying securities. The Fund's ELN investments are subject to the risk that issuers and/or counterparties will fail to make payments when due or default completely. Prices of the Fund's ELN investments may be adversely affected if any of the issuers or counterparties it is invested in are subject to an actual or perceived deterioration in their credit quality.

• <u><u>Risks Affecting Convertible Debt Obligations</u></u>. The market value of a convertible debt obligation may vary with changes in prevailing interest rates and changing evaluations of the ability of the issuer to meet principal and interest payments. The market value of a convertible debt obligation may also vary in accordance with the market value of the underlying stock. As a result, convertible debt obligations held by the Fund will tend to perform more like equity securities when the underlying stock price is high (because it is assumed that the Fund will convert the obligation), and more like non-convertible debt obligations when the underlying stock price is low (because it is assumed that the Fund will not convert the obligation). Because its market value can be influenced by several factors, a convertible debt obligation will not be as sensitive to interest rate changes as a similar non-convertible debt obligation, and generally will have less potential for gain or loss than the underlying stock.

• <u><u>Risks of Investing in U.S. Government Obligations</u></u>. U.S. government obligations are subject to the same risks affecting other debt obligations. Although securities backed by the full faith and credit of the U.S. government are commonly regarded as having relatively less risk of default, it is possible that the U.S. government may be unwilling or unable to repay principal and interest when due, and may require that the terms for payment be renegotiated. Further obligations that are backed by the full faith and credit of the U.S. government remain subject to the other general risks applicable to debt obligations, such as market risks, liquidity risks, and interest rate risks, and may be subject to ratings downgrades. U.S. government obligations also include obligations of U.S. government agencies, instrumentalities, and government-sponsored

THORNBURG Premium Income Builder ETF **SUMMARY PROSPECTUS** May 26, 2026

**4**

For the Fund's **Prospectus** or **SAI**, visit www.thornburg.com/download

enterprises, commonly referred to as "agency obligations." Some agency obligations are backed by the full faith and credit of the U.S. government, but other agency obligations have no specific backing or only limited support from the agency's authority to borrow from the U.S. government or the discretionary authority of the Treasury to purchase obligations of the issuing agency.

• <u><u>Risks of Debt Issued by Foreign Governments</u></u>. Debt obligations may be issued by foreign governments and their agencies and instrumentalities, including the governments of developing countries and "supra-national" entities such as the International Bank for Reconstruction and Development. The Fund's investments in these foreign debt obligations may be denominated in U.S. dollars or in foreign currencies. These securities, even if denominated in U.S. dollars, may be affected significantly by fluctuations in the value of foreign currencies, and the value of these securities in U.S. dollars may decline even if the securities increase in value in their home country. The governmental issuers of these debt obligations may be less willing or able than the U.S. to repay principal and interest when due, and may require that the terms for payment be renegotiated. In some countries there may be political instability or insufficient government supervision of markets, and the legal protections for the Fund's investments could be subject to unfavorable judicial or administrative changes. These risks may be more pronounced for the Fund's investments in debt obligations issued by developing countries.

• <u><u>Credit Risk</u></u>. If obligations held by the Fund are downgraded by ratings agencies or go into default, or if management action, legislation or other government action reduces the ability of issuers to pay principal and interest when due, the value of those obligations and the Fund's investment may decline. Because the ability of an issuer of a lower-rated or unrated obligation to pay principal and interest when due is typically less certain than for an issuer of a higher-rated obligation, lower-rated and unrated obligations are generally more vulnerable than higher-rated obligations to default, ratings downgrades and liquidity risk. Debt obligations backed by so-called "subprime" mortgages may also be subject to a greater risk of default or downgrade. Debt obligations issued by the U.S. government or its agencies, instrumentalities and government sponsored enterprises are also subject to credit risk. Securities backed by the full faith and credit of the U.S. government, such as U.S. Treasury obligations, are commonly regarded as having small exposure to credit risk. Obligations of certain U.S. agencies, instrumentalities and enterprises (sometimes referred to as "agency obligations") are not direct obligations of the U.S. government, may not be backed by the full faith and credit of the U.S. government and may have a greater exposure to credit risk.

• <u><u>High Yield Risk</u></u>. Debt obligations that are rated below investment grade and unrated obligations of similar credit quality (commonly referred to as "junk" or "high yield" bonds) may have a substantial risk of loss. These obligations are generally considered to be speculative with respect to the issuer's ability to pay interest and principal when due. These obligations may be subject to greater price volatility than investment grade obligations, and their prices may decline significantly in periods of general economic difficulty or in response to adverse publicity, changes in investor perceptions or other factors. These obligations may also be subject to greater liquidity risk.

• <u><u>Interest Rate Risk</u></u>. When interest rates increase, the value of the Fund's investments may decline and the Fund's share value may be reduced. This effect is typically more pronounced for intermediate and longer-term obligations. This effect is also typically more pronounced for mortgage- and other asset-backed securities, the value of which may fluctuate more significantly in response to interest rate changes. When interest rates decrease, the Fund's dividends may decline.

• <u><u>Prepayment and Extension Risk</u></u>. When market interest rates decline, certain debt obligations held by the Fund may be repaid more quickly than anticipated, requiring the Fund to reinvest the proceeds of those repayments in obligations which bear a lower interest rate. Conversely, when market interest rates increase, certain debt obligations held by the Fund may be repaid more slowly than anticipated, causing assets of the Fund to remain invested in relatively lower yielding obligations. These risks may be more pronounced for the Fund's investments in mortgage-backed and asset-backed securities.

• <u><u>Risks Affecting Mortgage-Backed Securities and Other Asset-Backed Securities</u></u>. Mortgage-backed securities are debt obligations, and are subject to the risks that affect debt obligations generally and which may adversely affect the value of mortgage-backed securities held by the Fund, including credit risk, interest rate risk, market and liquidity risks, prepayment risk and extension, and management risk. Because mortgage-backed securities represent interests in underlying mortgages, mortgage-backed securities are subject to the risks associated with those underlying mortgages, including delays or defaults in payments on those mortgages. During periods of declining interest rates, more mortgagors can be expected to prepay the remaining principal on their mortgages before the mortgages' scheduled maturity dates, reducing the value of mortgage-backed securities held by the Fund, and lowering the Fund's yield as it reinvests the prepayment proceeds at the lower prevailing interest rates. Conversely, during periods of rising interest rates, the rate of prepayment on the underlying mortgages can be expected to slow, and the Fund will not have those additional prepayment proceeds to invest in other securities at the higher prevailing interest rates. As with mortgage-backed securities, asset-backed securities are subject to the risks affecting debt obligations generally and which may adversely affect the value of asset-backed securities, held by the Fund, including credit risk, interest rate risk, market and liquidity risks, prepayment and extension risk, and management risk. These securities are subject to the risk of default by the issuer of the security and by the borrowers of the underlying loans in the pool. As with mortgage-backed securities, the market value and expected yield of asset-backed securities will vary in response to changes in prevailing interest rates and the rate of prepayment on the underlying loans.

• <u><u>Business Development Company ("BDC") Risk</u></u>. While the BDCs in which the Fund may invest are expected to include those that generate income in the form of dividends, certain BDCs during certain periods of time may not generate dividend income. The Fund will indirectly bear its proportionate share of any management fees and other operating expenses incurred by the BDCs and of any performance-based or incentive fees payable by the BDCs in which it invests, in addition to the Fund's management fee and any other expenses paid by the Fund. A BDC's incentive fee may be very high, vary from year to year and be payable even if the value of the BDC's portfolio declines in a given time period. The use of leverage by BDCs magnifies gains and losses on amounts invested and increases the risks associated with investing in BDCs. A BDC may make investments with a larger amount of risk of volatility and loss of principal than other investment options and may also be highly speculative and aggressive. Certain BDCs (or their underlying holdings) may also be difficult to value since many of the assets of BDCs do not have readily ascertainable market values. Therefore, such assets are most often recorded at fair value in accordance with valuation procedures adopted by such companies, which may potentially result in material differences between a BDC's net asset value per share and its market value.

• <u><u>Market and Economic Risk</u></u>. The value of the Fund's investments may decline and its share value may be reduced due to changes in general economic and market conditions. The value of a security may change in response to developments affecting entire economies, markets or industries, including changes in interest rates, political, legal, and technological developments, and general market volatility.

• <u><u>Risks Affecting Specific Countries or Regions</u></u>. If a significant portion of the Fund's assets is invested in issuers that are economically exposed to one country or region, the Fund's share value may be more susceptible to the conditions and developments in that country or region, and potentially more volatile than the share value of a more geographically diversified fund. A specific country or region could also be adversely

**5**

**SUMMARY PROSPECTUS** MAY 26, 2026 THORNBURG Premium Income Builder ETF

For the Fund's **Prospectus** or **SAI**, visit www.thornburg.com/download

affected by conditions or developments arising in other countries. For example, the U.S. government could take actions to prohibit or restrict individuals or companies within the U.S. from purchasing or holding the shares of issuers in another country, which may limit the Fund's ability to invest in that country or cause the Fund to have to sell investments in that country at less than desired prices. The nature and degree of the risks affecting a given country or region, and the extent of the Fund's exposure to any such country or region, is expected to vary over time.

• <u><u>Risks Affecting Specific Issuers</u></u>. The value of an equity security or debt obligation may decline in response to developments affecting the specific issuer of the obligation or security, even if the overall industry or economy is unaffected. These developments may include a variety of factors, including but not limited to management issues or other corporate disruption, a decline in revenues or profitability, an increase in costs, or an adverse effect on the issuer's competitive position.

• <u><u>Liquidity Risk</u></u>. Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell some or all of its investments promptly, or may only be able to sell investments at less than desired prices. The market for lower-rated and unrated debt obligations (including particularly "junk" or "high yield" bonds) and debt obligations backed by so-called "subprime" mortgages may be less liquid than the market for other obligations, making it difficult for the Fund to value its investment in a lower-rated or unrated obligation or to sell the investment in a timely manner or at an acceptable price.

• <u><u>Cybersecurity and Operational Risk</u></u>. Operational failures, cyber-attacks or other disruptions that affect the Fund's service providers, the Fund's counterparties, other market participants, or the issuers of securities held by the Fund may adversely affect the Fund and its shareholders, including by causing losses for the Fund or impairing Fund operations. The rapid development and increasingly widespread use of artificial intelligence, including machine learning technology and generative artificial intelligence such as ChatGPT, could exacerbate these risks.

**Performance**

The Fund is new and therefore has no performance history. Once the Fund has completed a full calendar year of operations, a bar chart and table will be included that will provide some indication of the risks of investing in the Fund by showing the variability of the Fund's returns and comparing the Fund's performance to a broad measure of market performance. The Fund's past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future.

When available, updated performance information can be obtained by calling toll-free 877-215-1330 or visiting <u><u>https://www.thornburg.com</u></u><u><u>.</u></u>

**Management**

*Investment Adviser:* Thornburg Investment Management, Inc.

*Portfolio Managers:*

Matt Burdett, a managing director and head of equities of Thornburg, has been one of the persons jointly and primarily responsible for the day-to-day management of the Fund since its inception in 2026.

Brian J. McMahon, the vice chairman of the Trust and a managing director and chief investment strategist of Thornburg, has been one of the persons jointly and primarily responsible for the day-to-day management of the Fund since its inception in 2026.

**Purchase and Sale of Shares**

The Fund will issue and redeem shares at its NAV only in Creation Units. These transactions are usually in exchange for a basket of securities and/or an amount of cash. As a practical matter, only Authorized Participants purchase or redeem Creation Units. Except when aggregated in Creation Units, shares are not redeemable securities of the Fund.

Individual shares of the Fund may only be purchased and sold in the secondary market (i.e., on a national securities exchange) through a broker or dealer at market prices. Because Fund shares trade at market prices rather than at NAV, Fund shares may trade at a price greater than NAV (premium) or less than NAV (discount). When buying or selling shares in the secondary market, you may incur costs attributable to the difference between the highest price a buyer is willing to pay to purchase shares of the Fund (bid) and the lowest price a seller is willing to accept for shares of the Fund (ask) (the "bid-ask spread"). When available, recent information regarding the Fund's NAV, market price, premiums and discounts, and bid-ask spreads will be available at <u><u>https://www.thornburg.com</u></u>.

**Tax Information**

The Fund's distributions may be comprised of taxable ordinary income, taxable capital gains and/or a non-taxable return of capital, unless you are investing through a tax-advantaged arrangement, such as a 401(k) plan or an individual retirement account. Investments through such tax-advantaged plans may be taxed upon withdrawal of monies from the tax-advantaged arrangement.

**Payments to Broker-Dealers and Other Financial Intermediaries**

If you purchase shares of the Fund through a broker-dealer or other financial intermediary (such as a bank), the Fund and/or the Adviser or principal underwriter may pay the intermediary for the sale of Fund shares and related services. These payments may create a conflict of interest by influencing the broker-dealer or other intermediary and your individual financial representative to recommend the Fund over another investment. Ask your individual financial representative or visit your financial intermediary's website for more information.

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