<SEC-DOCUMENT>0001387131-21-000064-index.html : 20210105
<SEC-HEADER>0001387131-21-000064.hdr.sgml : 20210105
<ACCEPTANCE-DATETIME>20210105111437
ACCESSION NUMBER:		0001387131-21-000064
CONFORMED SUBMISSION TYPE:	497
PUBLIC DOCUMENT COUNT:		2
FILED AS OF DATE:		20210105
DATE AS OF CHANGE:		20210105
EFFECTIVENESS DATE:		20210105

FILER:

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			THORNBURG INVESTMENT TRUST
		CENTRAL INDEX KEY:			0000816153
		IRS NUMBER:				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:		21504341

	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>
<EXISTING-SERIES-AND-CLASSES-CONTRACTS>
<SERIES>
<OWNER-CIK>0000816153
<SERIES-ID>S000000540
<SERIES-NAME>Thornburg Limited Term Municipal Fund
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000001427
<CLASS-CONTRACT-NAME>Thornburg Limited Term Municipal Fund - Class A
<CLASS-CONTRACT-TICKER-SYMBOL>LTMFX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000001438
<CLASS-CONTRACT-NAME>Thornburg Limited Term Municipal Fund - Class C
<CLASS-CONTRACT-TICKER-SYMBOL>LTMCX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000001449
<CLASS-CONTRACT-NAME>Thornburg Limited Term Municipal Fund - Class I
<CLASS-CONTRACT-TICKER-SYMBOL>LTMIX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000222321
<CLASS-CONTRACT-NAME>Thornburg Limited Term Municipal Fund - Class C2
<CLASS-CONTRACT-TICKER-SYMBOL>LTMQX
</CLASS-CONTRACT>
</SERIES>
<SERIES>
<OWNER-CIK>0000816153
<SERIES-ID>S000011841
<SERIES-NAME>Thornburg California Limited Term Municipal Fund
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000032344
<CLASS-CONTRACT-NAME>Thornburg California Limited Term Municipal Fund - Class A
<CLASS-CONTRACT-TICKER-SYMBOL>LTCAX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000032345
<CLASS-CONTRACT-NAME>Thornburg California Limited Term Municipal Fund - Class C
<CLASS-CONTRACT-TICKER-SYMBOL>LTCCX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000032346
<CLASS-CONTRACT-NAME>Thornburg California Limited Term Municipal Fund - Class I
<CLASS-CONTRACT-TICKER-SYMBOL>LTCIX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000222322
<CLASS-CONTRACT-NAME>Thornburg California Limited Term Municipal Fund - Class C2
<CLASS-CONTRACT-TICKER-SYMBOL>LTCQX
</CLASS-CONTRACT>
</SERIES>
<SERIES>
<OWNER-CIK>0000816153
<SERIES-ID>S000011842
<SERIES-NAME>Thornburg Limited Term U.S. Government Fund
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000032347
<CLASS-CONTRACT-NAME>Thornburg Limited Term U.S. Government Fund - Class A
<CLASS-CONTRACT-TICKER-SYMBOL>LTUSX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000032349
<CLASS-CONTRACT-NAME>Thornburg Limited Term U.S. Government Fund - Class C
<CLASS-CONTRACT-TICKER-SYMBOL>LTUCX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000032350
<CLASS-CONTRACT-NAME>Thornburg Limited Term U.S. Government Fund - Class I
<CLASS-CONTRACT-TICKER-SYMBOL>LTUIX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000042666
<CLASS-CONTRACT-NAME>Thornburg Limited Term U.S. Government Fund - Class R3
<CLASS-CONTRACT-TICKER-SYMBOL>LTURX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000113847
<CLASS-CONTRACT-NAME>Thornburg Limited Term U.S. Government Fund - Class R5
<CLASS-CONTRACT-TICKER-SYMBOL>LTGRX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000136848
<CLASS-CONTRACT-NAME>Thornburg Limited Term U.S. Government Fund - Class R4
<CLASS-CONTRACT-TICKER-SYMBOL>LTUGX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000222323
<CLASS-CONTRACT-NAME>Thornburg Limited Term U.S. Government Fund - Class C2
<CLASS-CONTRACT-TICKER-SYMBOL>LTUQX
</CLASS-CONTRACT>
</SERIES>
<SERIES>
<OWNER-CIK>0000816153
<SERIES-ID>S000011843
<SERIES-NAME>Thornburg New Mexico Intermediate Municipal Fund
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000032352
<CLASS-CONTRACT-NAME>Thornburg New Mexico Intermediate Municipal Fund - Class A
<CLASS-CONTRACT-TICKER-SYMBOL>THNMX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000032353
<CLASS-CONTRACT-NAME>Thornburg New Mexico Intermediate Municipal Fund - Class D
<CLASS-CONTRACT-TICKER-SYMBOL>THNDX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000042667
<CLASS-CONTRACT-NAME>Thornburg New Mexico Intermediate Municipal Fund - Class I
<CLASS-CONTRACT-TICKER-SYMBOL>THNIX
</CLASS-CONTRACT>
</SERIES>
<SERIES>
<OWNER-CIK>0000816153
<SERIES-ID>S000011844
<SERIES-NAME>Thornburg Intermediate Municipal Fund
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000032354
<CLASS-CONTRACT-NAME>Thornburg Intermediate Municipal Fund - Class A
<CLASS-CONTRACT-TICKER-SYMBOL>THIMX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000032355
<CLASS-CONTRACT-NAME>Thornburg Intermediate Municipal Fund - Class C
<CLASS-CONTRACT-TICKER-SYMBOL>THMCX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000032356
<CLASS-CONTRACT-NAME>Thornburg Intermediate Municipal Fund - Class I
<CLASS-CONTRACT-TICKER-SYMBOL>THMIX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000222324
<CLASS-CONTRACT-NAME>Thornburg Intermediate Municipal Fund - Class C2
<CLASS-CONTRACT-TICKER-SYMBOL>THMQX
</CLASS-CONTRACT>
</SERIES>
<SERIES>
<OWNER-CIK>0000816153
<SERIES-ID>S000011845
<SERIES-NAME>Thornburg Limited Term Income Fund
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000032357
<CLASS-CONTRACT-NAME>Thornburg Limited Term Income Fund - Class A
<CLASS-CONTRACT-TICKER-SYMBOL>THIFX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000032358
<CLASS-CONTRACT-NAME>Thornburg Limited Term Income Fund - Class C
<CLASS-CONTRACT-TICKER-SYMBOL>THICX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000032359
<CLASS-CONTRACT-NAME>Thornburg Limited Term Income Fund - Class I
<CLASS-CONTRACT-TICKER-SYMBOL>THIIX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000042668
<CLASS-CONTRACT-NAME>Thornburg Limited Term Income Fund - Class R3
<CLASS-CONTRACT-TICKER-SYMBOL>THIRX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000113848
<CLASS-CONTRACT-NAME>Thornburg Limited Term Income Fund - Class R5
<CLASS-CONTRACT-TICKER-SYMBOL>THRRX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000136849
<CLASS-CONTRACT-NAME>Thornburg Limited Term Income Fund - Class R4
<CLASS-CONTRACT-TICKER-SYMBOL>THRIX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000177478
<CLASS-CONTRACT-NAME>Thornburg Limited Term Income Fund - Class R6
<CLASS-CONTRACT-TICKER-SYMBOL>THRLX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000222325
<CLASS-CONTRACT-NAME>Thornburg Limited Term Income Fund - Class C2
<CLASS-CONTRACT-TICKER-SYMBOL>THIQX
</CLASS-CONTRACT>
</SERIES>
<SERIES>
<OWNER-CIK>0000816153
<SERIES-ID>S000011846
<SERIES-NAME>Thornburg Small/Mid Cap Core Fund
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000032361
<CLASS-CONTRACT-NAME>Thornburg Small/Mid Cap Core Fund - Class A
<CLASS-CONTRACT-TICKER-SYMBOL>TVAFX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000032363
<CLASS-CONTRACT-NAME>Thornburg Small/Mid Cap Core Fund - Class C
<CLASS-CONTRACT-TICKER-SYMBOL>TVCFX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000032364
<CLASS-CONTRACT-NAME>Thornburg Small/Mid Cap Core Fund - Class I
<CLASS-CONTRACT-TICKER-SYMBOL>TVIFX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000032366
<CLASS-CONTRACT-NAME>Thornburg Small/Mid Cap Core Fund - Class R5
<CLASS-CONTRACT-TICKER-SYMBOL>TVRRX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000042669
<CLASS-CONTRACT-NAME>Thornburg Small/Mid Cap Core Fund - Class R4
<CLASS-CONTRACT-TICKER-SYMBOL>TVIRX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000042670
<CLASS-CONTRACT-NAME>Thornburg Small/Mid Cap Core Fund - Class R3
<CLASS-CONTRACT-TICKER-SYMBOL>TVRFX
</CLASS-CONTRACT>
</SERIES>
<SERIES>
<OWNER-CIK>0000816153
<SERIES-ID>S000011848
<SERIES-NAME>Thornburg New York Intermediate Municipal Fund
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000032368
<CLASS-CONTRACT-NAME>Thornburg New York Intermediate Municipal Fund - Class A
<CLASS-CONTRACT-TICKER-SYMBOL>THNYX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000083544
<CLASS-CONTRACT-NAME>Thornburg New York Intermediate Municipal Fund - Class I
<CLASS-CONTRACT-TICKER-SYMBOL>TNYIX
</CLASS-CONTRACT>
</SERIES>
<SERIES>
<OWNER-CIK>0000816153
<SERIES-ID>S000011849
<SERIES-NAME>Thornburg International Value Fund
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000032369
<CLASS-CONTRACT-NAME>Thornburg International Value Fund - Class A
<CLASS-CONTRACT-TICKER-SYMBOL>TGVAX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000032371
<CLASS-CONTRACT-NAME>Thornburg International Value Fund - Class C
<CLASS-CONTRACT-TICKER-SYMBOL>THGCX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000032372
<CLASS-CONTRACT-NAME>Thornburg International Value Fund - Class I
<CLASS-CONTRACT-TICKER-SYMBOL>TGVIX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000032374
<CLASS-CONTRACT-NAME>Thornburg International Value Fund - Class R5
<CLASS-CONTRACT-TICKER-SYMBOL>TIVRX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000042671
<CLASS-CONTRACT-NAME>Thornburg International Value Fund - Class R4
<CLASS-CONTRACT-TICKER-SYMBOL>THVRX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000042672
<CLASS-CONTRACT-NAME>Thornburg International Value Fund - Class R3
<CLASS-CONTRACT-TICKER-SYMBOL>TGVRX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000113849
<CLASS-CONTRACT-NAME>Thornburg International Value Fund - Class R6
<CLASS-CONTRACT-TICKER-SYMBOL>TGIRX
</CLASS-CONTRACT>
</SERIES>
<SERIES>
<OWNER-CIK>0000816153
<SERIES-ID>S000011850
<SERIES-NAME>Thornburg Small/Mid Cap Growth Fund
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000032375
<CLASS-CONTRACT-NAME>Thornburg Small/Mid Cap Growth Fund - Class A
<CLASS-CONTRACT-TICKER-SYMBOL>THCGX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000032376
<CLASS-CONTRACT-NAME>Thornburg Small/Mid Cap Growth Fund - Class C
<CLASS-CONTRACT-TICKER-SYMBOL>TCGCX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000032377
<CLASS-CONTRACT-NAME>Thornburg Small/Mid Cap Growth Fund - Class I
<CLASS-CONTRACT-TICKER-SYMBOL>THIGX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000032379
<CLASS-CONTRACT-NAME>Thornburg Small/Mid Cap Growth Fund - Class R5
<CLASS-CONTRACT-TICKER-SYMBOL>THGRX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000042673
<CLASS-CONTRACT-NAME>Thornburg Small/Mid Cap Growth Fund - Class R4
<CLASS-CONTRACT-TICKER-SYMBOL>TCGRX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000042674
<CLASS-CONTRACT-NAME>Thornburg Small/Mid Cap Growth Fund - Class R3
<CLASS-CONTRACT-TICKER-SYMBOL>THCRX
</CLASS-CONTRACT>
</SERIES>
<SERIES>
<OWNER-CIK>0000816153
<SERIES-ID>S000011851
<SERIES-NAME>Thornburg Investment Income Builder Fund
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000032380
<CLASS-CONTRACT-NAME>Thornburg Investment Income Builder Fund - Class A
<CLASS-CONTRACT-TICKER-SYMBOL>TIBAX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000032381
<CLASS-CONTRACT-NAME>Thornburg Investment Income Builder Fund - Class C
<CLASS-CONTRACT-TICKER-SYMBOL>TIBCX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000032382
<CLASS-CONTRACT-NAME>Thornburg Investment Income Builder Fund - Class I
<CLASS-CONTRACT-TICKER-SYMBOL>TIBIX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000042675
<CLASS-CONTRACT-NAME>Thornburg Investment Income Builder Fund - Class R3
<CLASS-CONTRACT-TICKER-SYMBOL>TIBRX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000047041
<CLASS-CONTRACT-NAME>Thornburg Investment Income Builder Fund - Class R5
<CLASS-CONTRACT-TICKER-SYMBOL>TIBMX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000058461
<CLASS-CONTRACT-NAME>Thornburg Investment Income Builder Fund - Class R4
<CLASS-CONTRACT-TICKER-SYMBOL>TIBGX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000177479
<CLASS-CONTRACT-NAME>Thornburg Investment Income Builder Fund - Class R6
<CLASS-CONTRACT-TICKER-SYMBOL>TIBOX
</CLASS-CONTRACT>
</SERIES>
<SERIES>
<OWNER-CIK>0000816153
<SERIES-ID>S000012859
<SERIES-NAME>Thornburg Global Opportunities Fund
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000034775
<CLASS-CONTRACT-NAME>Thornburg Global Opportunities Fund - Class A
<CLASS-CONTRACT-TICKER-SYMBOL>THOAX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000034776
<CLASS-CONTRACT-NAME>Thornburg Global Opportunities Fund - Class C
<CLASS-CONTRACT-TICKER-SYMBOL>THOCX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000034777
<CLASS-CONTRACT-NAME>Thornburg Global Opportunities Fund - Class I
<CLASS-CONTRACT-TICKER-SYMBOL>THOIX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000058462
<CLASS-CONTRACT-NAME>Thornburg Global Opportunities Fund - Class R3
<CLASS-CONTRACT-TICKER-SYMBOL>THORX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000058463
<CLASS-CONTRACT-NAME>Thornburg Global Opportunities Fund - Class R4
<CLASS-CONTRACT-TICKER-SYMBOL>THOVX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000058464
<CLASS-CONTRACT-NAME>Thornburg Global Opportunities Fund - Class R5
<CLASS-CONTRACT-TICKER-SYMBOL>THOFX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000177480
<CLASS-CONTRACT-NAME>Thornburg Global Opportunities Fund - Class R6
<CLASS-CONTRACT-TICKER-SYMBOL>THOGX
</CLASS-CONTRACT>
</SERIES>
<SERIES>
<OWNER-CIK>0000816153
<SERIES-ID>S000015648
<SERIES-NAME>Thornburg International Growth Fund
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000042663
<CLASS-CONTRACT-NAME>Thornburg International Growth Fund - Class I
<CLASS-CONTRACT-TICKER-SYMBOL>TINGX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000042664
<CLASS-CONTRACT-NAME>Thornburg International Growth Fund - Class A
<CLASS-CONTRACT-TICKER-SYMBOL>TIGAX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000042665
<CLASS-CONTRACT-NAME>Thornburg International Growth Fund - Class C
<CLASS-CONTRACT-TICKER-SYMBOL>TIGCX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000058465
<CLASS-CONTRACT-NAME>Thornburg International Growth Fund - Class R3
<CLASS-CONTRACT-TICKER-SYMBOL>TIGVX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000058466
<CLASS-CONTRACT-NAME>Thornburg International Growth Fund - Class R4
<CLASS-CONTRACT-TICKER-SYMBOL>TINVX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000058467
<CLASS-CONTRACT-NAME>Thornburg International Growth Fund - Class R5
<CLASS-CONTRACT-TICKER-SYMBOL>TINFX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000123223
<CLASS-CONTRACT-NAME>Thornburg International Growth Fund - Class R6
<CLASS-CONTRACT-TICKER-SYMBOL>THGIX
</CLASS-CONTRACT>
</SERIES>
<SERIES>
<OWNER-CIK>0000816153
<SERIES-ID>S000020097
<SERIES-NAME>Thornburg Strategic Income Fund
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000056389
<CLASS-CONTRACT-NAME>Thornburg Strategic Income Fund - Class A
<CLASS-CONTRACT-TICKER-SYMBOL>TSIAX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000056390
<CLASS-CONTRACT-NAME>Thornburg Strategic Income Fund - Class C
<CLASS-CONTRACT-TICKER-SYMBOL>TSICX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000056391
<CLASS-CONTRACT-NAME>Thornburg Strategic Income Fund - Class I
<CLASS-CONTRACT-TICKER-SYMBOL>TSIIX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000113850
<CLASS-CONTRACT-NAME>Thornburg Strategic Income Fund - Class R3
<CLASS-CONTRACT-TICKER-SYMBOL>TSIRX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000113851
<CLASS-CONTRACT-NAME>Thornburg Strategic Income Fund - Class R5
<CLASS-CONTRACT-TICKER-SYMBOL>TSRRX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000136850
<CLASS-CONTRACT-NAME>Thornburg Strategic Income Fund - Class R4
<CLASS-CONTRACT-TICKER-SYMBOL>TSRIX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000177481
<CLASS-CONTRACT-NAME>Thornburg Strategic Income Fund - Class R6
<CLASS-CONTRACT-TICKER-SYMBOL>TSRSX
</CLASS-CONTRACT>
</SERIES>
<SERIES>
<OWNER-CIK>0000816153
<SERIES-ID>S000025152
<SERIES-NAME>Thornburg Strategic Municipal Income Fund
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000075018
<CLASS-CONTRACT-NAME>Thornburg Strategic Municipal Income Fund Class A
<CLASS-CONTRACT-TICKER-SYMBOL>TSSAX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000075019
<CLASS-CONTRACT-NAME>Thornburg Strategic Municipal Income Fund Class C
<CLASS-CONTRACT-TICKER-SYMBOL>TSSCX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000075020
<CLASS-CONTRACT-NAME>Thornburg Strategic Municipal Income Fund Class I
<CLASS-CONTRACT-TICKER-SYMBOL>TSSIX
</CLASS-CONTRACT>
</SERIES>
<SERIES>
<OWNER-CIK>0000816153
<SERIES-ID>S000027135
<SERIES-NAME>Thornburg Developing World Fund
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000081859
<CLASS-CONTRACT-NAME>Thornburg Developing World Fund Class A
<CLASS-CONTRACT-TICKER-SYMBOL>THDAX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000081860
<CLASS-CONTRACT-NAME>Thornburg Developing World Fund Class C
<CLASS-CONTRACT-TICKER-SYMBOL>THDCX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000081861
<CLASS-CONTRACT-NAME>Thornburg Developing World Fund Class I
<CLASS-CONTRACT-TICKER-SYMBOL>THDIX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000123224
<CLASS-CONTRACT-NAME>Thornburg Developing World Fund Class R5
<CLASS-CONTRACT-TICKER-SYMBOL>THDRX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000123225
<CLASS-CONTRACT-NAME>Thornburg Developing World Fund Class R6
<CLASS-CONTRACT-TICKER-SYMBOL>TDWRX
</CLASS-CONTRACT>
</SERIES>
<SERIES>
<OWNER-CIK>0000816153
<SERIES-ID>S000043669
<SERIES-NAME>Thornburg Short Duration Municipal Fund
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000135383
<CLASS-CONTRACT-NAME>Thornburg Short Duration Municipal Fund Class A
<CLASS-CONTRACT-TICKER-SYMBOL>TLMAX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000135384
<CLASS-CONTRACT-NAME>Thornburg Short Duration Municipal Fund Class I
<CLASS-CONTRACT-TICKER-SYMBOL>TLMIX
</CLASS-CONTRACT>
</SERIES>
<SERIES>
<OWNER-CIK>0000816153
<SERIES-ID>S000043670
<SERIES-NAME>Thornburg Ultra Short Income Fund
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000135385
<CLASS-CONTRACT-NAME>Thornburg Ultra Short Income Fund Class A
<CLASS-CONTRACT-TICKER-SYMBOL>TLDAX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000135386
<CLASS-CONTRACT-NAME>Thornburg Ultra Short Income Fund Class I
<CLASS-CONTRACT-TICKER-SYMBOL>TLDIX
</CLASS-CONTRACT>
</SERIES>
<SERIES>
<OWNER-CIK>0000816153
<SERIES-ID>S000050704
<SERIES-NAME>Thornburg Better World International Fund
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000160136
<CLASS-CONTRACT-NAME>Thornburg Better World International Fund - Class A
<CLASS-CONTRACT-TICKER-SYMBOL>TBWAX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000160137
<CLASS-CONTRACT-NAME>Thornburg Better World International Fund - Class C
<CLASS-CONTRACT-TICKER-SYMBOL>TBWCX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000160138
<CLASS-CONTRACT-NAME>Thornburg Better World International Fund - Class I
<CLASS-CONTRACT-TICKER-SYMBOL>TBWIX
</CLASS-CONTRACT>
</SERIES>
<SERIES>
<OWNER-CIK>0000816153
<SERIES-ID>S000056004
<SERIES-NAME>Thornburg Long/Short Equity Fund
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000176362
<CLASS-CONTRACT-NAME>Thornburg Long/Short Equity Fund- Class I
<CLASS-CONTRACT-TICKER-SYMBOL>THLSX
</CLASS-CONTRACT>
</SERIES>
<SERIES>
<OWNER-CIK>0000816153
<SERIES-ID>S000064930
<SERIES-NAME>Thornburg Summit Fund
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000210187
<CLASS-CONTRACT-NAME>Thornburg Summit Fund - Class A
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000210188
<CLASS-CONTRACT-NAME>Thornburg Summit Fund - Class I
<CLASS-CONTRACT-TICKER-SYMBOL>TSUMX
</CLASS-CONTRACT>
</SERIES>
</EXISTING-SERIES-AND-CLASSES-CONTRACTS>
</SERIES-AND-CLASSES-CONTRACTS-DATA>
</SEC-HEADER>
<DOCUMENT>
<TYPE>497
<SEQUENCE>1
<FILENAME>tbit-497_010521.htm
<DESCRIPTION>DEFINITIVE MATERIALS
<TEXT>
Document 1 - file: tbit-497_010521.htm
</DOCUMENT> <DOCUMENT> <TYPE>GRAPHIC <SEQUENCE>2 <FILENAME>tbit-497_010521img001.gif <DESCRIPTION>GRAPHIC <TEXT> Document 2 - file: tbit-497_010521img001.gif
</DOCUMENT> </SEC-DOCUMENT>