# EDGAR Filing Document

**Accession Number:** 0000816153
**File Stem:** 0001999371-25-013108
**Filing Date:** 2025-9
**Character Count:** 21990
**Document Hash:** f34c88d1d154e228eae7740b9a8808a1
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001999371-25-013108.hdr.sgml**: 20250911

**ACCESSION NUMBER**: 0001999371-25-013108

**CONFORMED SUBMISSION TYPE**: 497

**PUBLIC DOCUMENT COUNT**: 2

**FILED AS OF DATE**: 20250911

**DATE AS OF CHANGE**: 20250911

**EFFECTIVENESS DATE**: 20250911

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** THORNBURG INVESTMENT TRUST
- **CENTRAL INDEX KEY:** 0000816153

**ORGANIZATION NAME:**
- **EIN:** 061158764
- **STATE OF INCORPORATION:** MA
- **FISCAL YEAR END:** 0930

**FILING VALUES:**
- **FORM TYPE:** 497
- **SEC ACT:** 1933 Act
- **SEC FILE NUMBER:** 033-14905
- **FILM NUMBER:** 251309379

**BUSINESS ADDRESS:**
- **STREET 1:** 2300 NORTH RIDGETOP ROAD
- **CITY:** SANTA FE
- **STATE:** NM
- **ZIP:** 87506-8361
- **BUSINESS PHONE:** 5059840200

**MAIL ADDRESS:**
- **STREET 1:** 2300 NORTH RIDGETOP ROAD
- **CITY:** SANTA FE
- **STATE:** NM
- **ZIP:** 87506-8361

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** THORNBURG INCOME TRUST
- **DATE OF NAME CHANGE:** 19920703

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** LIMITED TERM TRUST
- **DATE OF NAME CHANGE:** 19870816

## Series and Classes Contracts Data

### Thornburg Limited Term Municipal Fund (Series ID: S000000540)

---

|  |  |  |
|:---|:---|:---|
| Class Name                                       | Ticker Symbol | Class ID   |
| Thornburg Limited Term Municipal Fund - Class A  | LTMFX         | C000001427 |
| Thornburg Limited Term Municipal Fund - Class C  | LTMCX         | C000001438 |
| Thornburg Limited Term Municipal Fund - Class I  | LTMIX         | C000001449 |
| Thornburg Limited Term Municipal Fund - Class C2 | LTMQX         | C000222321 |

---

### Thornburg California Limited Term Municipal Fund (Series ID: S000011841)

---

|  |  |  |
|:---|:---|:---|
| Class Name                                                  | Ticker Symbol | Class ID   |
| Thornburg California Limited Term Municipal Fund - Class A  | LTCAX         | C000032344 |
| Thornburg California Limited Term Municipal Fund - Class C  | LTCCX         | C000032345 |
| Thornburg California Limited Term Municipal Fund - Class I  | LTCIX         | C000032346 |
| Thornburg California Limited Term Municipal Fund - Class C2 | LTCQX         | C000222322 |

---

### Thornburg Limited Term U.S. Government Fund (Series ID: S000011842)

---

|  |  |  |
|:---|:---|:---|
| Class Name                                             | Ticker Symbol | Class ID   |
| Thornburg Limited Term U.S. Government Fund - Class A  | LTUSX         | C000032347 |
| Thornburg Limited Term U.S. Government Fund - Class C  | LTUCX         | C000032349 |
| Thornburg Limited Term U.S. Government Fund - Class I  | LTUIX         | C000032350 |
| Thornburg Limited Term U.S. Government Fund - Class C2 | LTUQX         | C000222323 |

---

### Thornburg New Mexico Intermediate Municipal Fund (Series ID: S000011843)

---

|  |  |  |
|:---|:---|:---|
| Class Name                                                 | Ticker Symbol | Class ID   |
| Thornburg New Mexico Intermediate Municipal Fund - Class A | THNMX         | C000032352 |
| Thornburg New Mexico Intermediate Municipal Fund - Class D | THNDX         | C000032353 |
| Thornburg New Mexico Intermediate Municipal Fund - Class I | THNIX         | C000042667 |

---

### Thornburg Intermediate Municipal Fund (Series ID: S000011844)

---

|  |  |  |
|:---|:---|:---|
| Class Name                                       | Ticker Symbol | Class ID   |
| Thornburg Intermediate Municipal Fund - Class A  | THIMX         | C000032354 |
| Thornburg Intermediate Municipal Fund - Class C  | THMCX         | C000032355 |
| Thornburg Intermediate Municipal Fund - Class I  | THMIX         | C000032356 |
| Thornburg Intermediate Municipal Fund - Class C2 | THMQX         | C000222324 |

---

### Thornburg Limited Term Income Fund (Series ID: S000011845)

---

|  |  |  |
|:---|:---|:---|
| Class Name                                    | Ticker Symbol | Class ID   |
| Thornburg Limited Term Income Fund - Class A  | THIFX         | C000032357 |
| Thornburg Limited Term Income Fund - Class C  | THICX         | C000032358 |
| Thornburg Limited Term Income Fund - Class I  | THIIX         | C000032359 |
| Thornburg Limited Term Income Fund - Class C2 | THIQX         | C000222325 |

---

### Thornburg Small/Mid Cap Core Fund (Series ID: S000011846)

---

|  |  |  |
|:---|:---|:---|
| Class Name                                  | Ticker Symbol | Class ID   |
| Thornburg Small/Mid Cap Core Fund - Class A | TVAFX         | C000032361 |
| Thornburg Small/Mid Cap Core Fund - Class C | TVCFX         | C000032363 |
| Thornburg Small/Mid Cap Core Fund - Class I | TVIFX         | C000032364 |

---

### Thornburg New York Intermediate Municipal Fund (Series ID: S000011848)

---

|  |  |  |
|:---|:---|:---|
| Class Name                                               | Ticker Symbol | Class ID   |
| Thornburg New York Intermediate Municipal Fund - Class A | THNYX         | C000032368 |
| Thornburg New York Intermediate Municipal Fund - Class I | TNYIX         | C000083544 |

---

### Thornburg International Equity Fund (Series ID: S000011849)

---

|  |  |  |
|:---|:---|:---|
| Class Name                                    | Ticker Symbol | Class ID   |
| Thornburg International Equity Fund - Class A | TGVAX         | C000032369 |
| Thornburg International Equity Fund - Class C | THGCX         | C000032371 |
| Thornburg International Equity Fund - Class I | TGVIX         | C000032372 |

---

### Thornburg Small/Mid Cap Growth Fund (Series ID: S000011850)

---

|  |  |  |
|:---|:---|:---|
| Class Name                                    | Ticker Symbol | Class ID   |
| Thornburg Small/Mid Cap Growth Fund - Class A | THCGX         | C000032375 |
| Thornburg Small/Mid Cap Growth Fund - Class C | TCGCX         | C000032376 |
| Thornburg Small/Mid Cap Growth Fund - Class I | THIGX         | C000032377 |

---

### Thornburg Investment Income Builder Fund (Series ID: S000011851)

---

|  |  |  |
|:---|:---|:---|
| Class Name                                         | Ticker Symbol | Class ID   |
| Thornburg Investment Income Builder Fund - Class A | TIBAX         | C000032380 |
| Thornburg Investment Income Builder Fund - Class C | TIBCX         | C000032381 |
| Thornburg Investment Income Builder Fund - Class I | TIBIX         | C000032382 |

---

### Thornburg Global Opportunities Fund (Series ID: S000012859)

---

|  |  |  |
|:---|:---|:---|
| Class Name                                    | Ticker Symbol | Class ID   |
| Thornburg Global Opportunities Fund - Class A | THOAX         | C000034775 |
| Thornburg Global Opportunities Fund - Class C | THOCX         | C000034776 |
| Thornburg Global Opportunities Fund - Class I | THOIX         | C000034777 |

---

### Thornburg International Growth Fund (Series ID: S000015648)

---

|  |  |  |
|:---|:---|:---|
| Class Name                                    | Ticker Symbol | Class ID   |
| Thornburg International Growth Fund - Class I | TINGX         | C000042663 |
| Thornburg International Growth Fund - Class A | TIGAX         | C000042664 |
| Thornburg International Growth Fund - Class C | TIGCX         | C000042665 |

---

### Thornburg Strategic Income Fund (Series ID: S000020097)

---

|  |  |  |
|:---|:---|:---|
| Class Name                                | Ticker Symbol | Class ID   |
| Thornburg Strategic Income Fund - Class A | TSIAX         | C000056389 |
| Thornburg Strategic Income Fund - Class C | TSICX         | C000056390 |
| Thornburg Strategic Income Fund - Class I | TSIIX         | C000056391 |

---

### Thornburg Strategic Municipal Income Fund (Series ID: S000025152)

---

|  |  |  |
|:---|:---|:---|
| Class Name                                        | Ticker Symbol | Class ID   |
| Thornburg Strategic Municipal Income Fund Class A | TSSAX         | C000075018 |
| Thornburg Strategic Municipal Income Fund Class C | TSSCX         | C000075019 |
| Thornburg Strategic Municipal Income Fund Class I | TSSIX         | C000075020 |

---

### Thornburg Developing World Fund (Series ID: S000027135)

---

|  |  |  |
|:---|:---|:---|
| Class Name                              | Ticker Symbol | Class ID   |
| Thornburg Developing World Fund Class A | THDAX         | C000081859 |
| Thornburg Developing World Fund Class C | THDCX         | C000081860 |
| Thornburg Developing World Fund Class I | THDIX         | C000081861 |

---

### Thornburg Short Duration Municipal Fund (Series ID: S000043669)

---

|  |  |  |
|:---|:---|:---|
| Class Name                                      | Ticker Symbol | Class ID   |
| Thornburg Short Duration Municipal Fund Class A | TLMAX         | C000135383 |
| Thornburg Short Duration Municipal Fund Class I | TLMIX         | C000135384 |

---

### Thornburg Ultra Short Income Fund (Series ID: S000043670)

---

|  |  |  |
|:---|:---|:---|
| Class Name                                | Ticker Symbol | Class ID   |
| Thornburg Ultra Short Income Fund Class A | TLDAX         | C000135385 |
| Thornburg Ultra Short Income Fund Class I | TLDIX         | C000135386 |

---

### Thornburg Better World International Fund (Series ID: S000050704)

---

|  |  |  |
|:---|:---|:---|
| Class Name                                          | Ticker Symbol | Class ID   |
| Thornburg Better World International Fund - Class A | TBWAX         | C000160136 |
| Thornburg Better World International Fund - Class C | TBWCX         | C000160137 |
| Thornburg Better World International Fund - Class I | TBWIX         | C000160138 |

---

### Thornburg Summit Fund (Series ID: S000064930)

---

|  |  |  |
|:---|:---|:---|
| Class Name                      | Ticker Symbol | Class ID   |
| Thornburg Summit Fund - Class A | TSAMX         | C000210187 |
| Thornburg Summit Fund - Class I | TSUMX         | C000210188 |

---

### Thornburg Core Plus Bond Fund (Series ID: S000082059)

---

|  |  |  |
|:---|:---|:---|
| Class Name | Ticker Symbol | Class ID   |
| Class A    | THCAX         | C000245318 |
| Class I    | THCIX         | C000245319 |
| Class C    | THCCX         | C000245320 |

---

## Series and Classes Contracts Data

### Thornburg Limited Term Municipal Fund (Series ID: S000000540)

| Class ID   | Class Name                                       | Ticker Symbol   |
|:---|:---|:---|
| C000001427 | Thornburg Limited Term Municipal Fund - Class A  | LTMFX           |
| C000001438 | Thornburg Limited Term Municipal Fund - Class C  | LTMCX           |
| C000001449 | Thornburg Limited Term Municipal Fund - Class I  | LTMIX           |
| C000222321 | Thornburg Limited Term Municipal Fund - Class C2 | LTMQX           |

### Thornburg California Limited Term Municipal Fund (Series ID: S000011841)

| Class ID   | Class Name                                                  | Ticker Symbol   |
|:---|:---|:---|
| C000032344 | Thornburg California Limited Term Municipal Fund - Class A  | LTCAX           |
| C000032345 | Thornburg California Limited Term Municipal Fund - Class C  | LTCCX           |
| C000032346 | Thornburg California Limited Term Municipal Fund - Class I  | LTCIX           |
| C000222322 | Thornburg California Limited Term Municipal Fund - Class C2 | LTCQX           |

### Thornburg Limited Term U.S. Government Fund (Series ID: S000011842)

| Class ID   | Class Name                                             | Ticker Symbol   |
|:---|:---|:---|
| C000032347 | Thornburg Limited Term U.S. Government Fund - Class A  | LTUSX           |
| C000032349 | Thornburg Limited Term U.S. Government Fund - Class C  | LTUCX           |
| C000032350 | Thornburg Limited Term U.S. Government Fund - Class I  | LTUIX           |
| C000222323 | Thornburg Limited Term U.S. Government Fund - Class C2 | LTUQX           |

### Thornburg New Mexico Intermediate Municipal Fund (Series ID: S000011843)

| Class ID   | Class Name                                                 | Ticker Symbol   |
|:---|:---|:---|
| C000032352 | Thornburg New Mexico Intermediate Municipal Fund - Class A | THNMX           |
| C000032353 | Thornburg New Mexico Intermediate Municipal Fund - Class D | THNDX           |
| C000042667 | Thornburg New Mexico Intermediate Municipal Fund - Class I | THNIX           |

### Thornburg Intermediate Municipal Fund (Series ID: S000011844)

| Class ID   | Class Name                                       | Ticker Symbol   |
|:---|:---|:---|
| C000032354 | Thornburg Intermediate Municipal Fund - Class A  | THIMX           |
| C000032355 | Thornburg Intermediate Municipal Fund - Class C  | THMCX           |
| C000032356 | Thornburg Intermediate Municipal Fund - Class I  | THMIX           |
| C000222324 | Thornburg Intermediate Municipal Fund - Class C2 | THMQX           |

### Thornburg Limited Term Income Fund (Series ID: S000011845)

| Class ID   | Class Name                                    | Ticker Symbol   |
|:---|:---|:---|
| C000032357 | Thornburg Limited Term Income Fund - Class A  | THIFX           |
| C000032358 | Thornburg Limited Term Income Fund - Class C  | THICX           |
| C000032359 | Thornburg Limited Term Income Fund - Class I  | THIIX           |
| C000222325 | Thornburg Limited Term Income Fund - Class C2 | THIQX           |

### Thornburg Small/Mid Cap Core Fund (Series ID: S000011846)

| Class ID   | Class Name                                  | Ticker Symbol   |
|:---|:---|:---|
| C000032361 | Thornburg Small/Mid Cap Core Fund - Class A | TVAFX           |
| C000032363 | Thornburg Small/Mid Cap Core Fund - Class C | TVCFX           |
| C000032364 | Thornburg Small/Mid Cap Core Fund - Class I | TVIFX           |

### Thornburg New York Intermediate Municipal Fund (Series ID: S000011848)

| Class ID   | Class Name                                               | Ticker Symbol   |
|:---|:---|:---|
| C000032368 | Thornburg New York Intermediate Municipal Fund - Class A | THNYX           |
| C000083544 | Thornburg New York Intermediate Municipal Fund - Class I | TNYIX           |

### Thornburg International Equity Fund (Series ID: S000011849)

| Class ID   | Class Name                                    | Ticker Symbol   |
|:---|:---|:---|
| C000032369 | Thornburg International Equity Fund - Class A | TGVAX           |
| C000032371 | Thornburg International Equity Fund - Class C | THGCX           |
| C000032372 | Thornburg International Equity Fund - Class I | TGVIX           |

### Thornburg Small/Mid Cap Growth Fund (Series ID: S000011850)

| Class ID   | Class Name                                    | Ticker Symbol   |
|:---|:---|:---|
| C000032375 | Thornburg Small/Mid Cap Growth Fund - Class A | THCGX           |
| C000032376 | Thornburg Small/Mid Cap Growth Fund - Class C | TCGCX           |
| C000032377 | Thornburg Small/Mid Cap Growth Fund - Class I | THIGX           |

### Thornburg Investment Income Builder Fund (Series ID: S000011851)

| Class ID   | Class Name                                         | Ticker Symbol   |
|:---|:---|:---|
| C000032380 | Thornburg Investment Income Builder Fund - Class A | TIBAX           |
| C000032381 | Thornburg Investment Income Builder Fund - Class C | TIBCX           |
| C000032382 | Thornburg Investment Income Builder Fund - Class I | TIBIX           |

### Thornburg Global Opportunities Fund (Series ID: S000012859)

| Class ID   | Class Name                                    | Ticker Symbol   |
|:---|:---|:---|
| C000034775 | Thornburg Global Opportunities Fund - Class A | THOAX           |
| C000034776 | Thornburg Global Opportunities Fund - Class C | THOCX           |
| C000034777 | Thornburg Global Opportunities Fund - Class I | THOIX           |

### Thornburg International Growth Fund (Series ID: S000015648)

| Class ID   | Class Name                                    | Ticker Symbol   |
|:---|:---|:---|
| C000042663 | Thornburg International Growth Fund - Class I | TINGX           |
| C000042664 | Thornburg International Growth Fund - Class A | TIGAX           |
| C000042665 | Thornburg International Growth Fund - Class C | TIGCX           |

### Thornburg Strategic Income Fund (Series ID: S000020097)

| Class ID   | Class Name                                | Ticker Symbol   |
|:---|:---|:---|
| C000056389 | Thornburg Strategic Income Fund - Class A | TSIAX           |
| C000056390 | Thornburg Strategic Income Fund - Class C | TSICX           |
| C000056391 | Thornburg Strategic Income Fund - Class I | TSIIX           |

### Thornburg Strategic Municipal Income Fund (Series ID: S000025152)

| Class ID   | Class Name                                        | Ticker Symbol   |
|:---|:---|:---|
| C000075018 | Thornburg Strategic Municipal Income Fund Class A | TSSAX           |
| C000075019 | Thornburg Strategic Municipal Income Fund Class C | TSSCX           |
| C000075020 | Thornburg Strategic Municipal Income Fund Class I | TSSIX           |

### Thornburg Developing World Fund (Series ID: S000027135)

| Class ID   | Class Name                              | Ticker Symbol   |
|:---|:---|:---|
| C000081859 | Thornburg Developing World Fund Class A | THDAX           |
| C000081860 | Thornburg Developing World Fund Class C | THDCX           |
| C000081861 | Thornburg Developing World Fund Class I | THDIX           |

### Thornburg Short Duration Municipal Fund (Series ID: S000043669)

| Class ID   | Class Name                                      | Ticker Symbol   |
|:---|:---|:---|
| C000135383 | Thornburg Short Duration Municipal Fund Class A | TLMAX           |
| C000135384 | Thornburg Short Duration Municipal Fund Class I | TLMIX           |

### Thornburg Ultra Short Income Fund (Series ID: S000043670)

| Class ID   | Class Name                                | Ticker Symbol   |
|:---|:---|:---|
| C000135385 | Thornburg Ultra Short Income Fund Class A | TLDAX           |
| C000135386 | Thornburg Ultra Short Income Fund Class I | TLDIX           |

### Thornburg Better World International Fund (Series ID: S000050704)

| Class ID   | Class Name                                          | Ticker Symbol   |
|:---|:---|:---|
| C000160136 | Thornburg Better World International Fund - Class A | TBWAX           |
| C000160137 | Thornburg Better World International Fund - Class C | TBWCX           |
| C000160138 | Thornburg Better World International Fund - Class I | TBWIX           |

### Thornburg Summit Fund (Series ID: S000064930)

| Class ID   | Class Name                      | Ticker Symbol   |
|:---|:---|:---|
| C000210187 | Thornburg Summit Fund - Class A | TSAMX           |
| C000210188 | Thornburg Summit Fund - Class I | TSUMX           |

### Thornburg Core Plus Bond Fund (Series ID: S000082059)

| Class ID   | Class Name   | Ticker Symbol   |
|:---|:---|:---|
| C000245318 | Class A      | THCAX           |
| C000245319 | Class I      | THCIX           |
| C000245320 | Class C      | THCCX           |

![](tbit-497_091125img001.gif)

**THORNBURG INVESTMENT TRUST SUPPLEMENT**

Dated September 11, 2025

to the

**THORNBURG FUNDS PROSPECTUS** 

applicable to Class A, C, C2, D and I shares<br>dated February 1, 2025, as supplemented April 1, 2025 and April 23, 2025<br>**(the "Prospectus")**

*Effective immediately, Class A and Class I shares of the Funds will be available for purchase, sale and exchange to employer-sponsored retirement plans or profit-sharing plans that qualify under sections 401(a), 403(b) and 457 of the Internal Revenue Code of 1986, as amended (such as a 401(k) plan, money purchase pension plan, defined benefit plan, Taft-Hartley multi-employer plan, and a multi-participant health savings account), regardless of whether the shares to be purchased by the employer-sponsored retirement plan will be held in the name of that employer-sponsored retirement plan or in an omnibus account maintained by a financial intermediary that provides recordkeeping services to such plans. In accordance with the foregoing, the Prospectus is amended as follows:*

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;•The section entitled "Purchases by Employer-Sponsored Retirement Plans," on page 164 of the Prospectus, is hereby deleted.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;•The seventh bullet point under the heading "Class A Sales Charge Waivers," on page 170 of the Prospectus, is revised to read as follows:

"Purchases by an employer-sponsored retirement plan."

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;•The third bullet point under the heading "Information about Class I Shares," on page 174 of the Prospectus, is revised to read as follows:

"Employer-sponsored retirement plans."

The Funds will not impose any investment minimums on the purchase of Class A or Class I shares by such plans. The plan or financial intermediary through which you purchase Class A or Class I shares may, however, impose its own investment minimums. The Fund is not responsible for notifying you of any investment minimums that your plan or financial intermediary may impose, or for any changes to such minimums, so please contact your plan administrator or financial intermediary for more information.

*Also, effective immediately, the first sentence of the section entitled "Exchanging Fund Shares" on page 175 of the Prospectus is replaced with the following:*

"Subject to the bullet points below, shareholders are allowed to exchange their shares of a Fund for shares of the same class of another Fund without the imposition of any sales charge, fee, or other charge imposed being either Fund. Additionally, and subject to the bullet points below, shareholders are allowed to exchange their shares of a Fund for a different class of shares of that Fund or another Fund, with the exception of any exchange that would result in the payment of a commission on the purchase side of the exchange."

PLEASE KEEP THIS SUPPLEMENT FOR FUTURE REFERENCE

TH6686