~ http://Thornburg.com/role/ShareholderFeesData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000012859Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

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~ http://Thornburg.com/role/ExpenseExample column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000012859Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ExpenseExampleNoRedemption column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000012859Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/BarChartData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000012859Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/PerformanceTableData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000012859Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ShareholderFeesData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011849Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/OperatingExpensesData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011849Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ExpenseExample column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011849Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ExpenseExampleNoRedemption column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011849Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/BarChartData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011849Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/PerformanceTableData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011849Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ShareholderFeesData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000050704Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/OperatingExpensesData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000050704Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ExpenseExample column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000050704Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ExpenseExampleNoRedemption column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000050704Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/BarChartData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000050704Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/PerformanceTableData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000050704Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ShareholderFeesData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000015648Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/OperatingExpensesData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000015648Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ExpenseExample column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000015648Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ExpenseExampleNoRedemption column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000015648Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/BarChartData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000015648Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/PerformanceTableData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000015648Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ShareholderFeesData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000027135Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/OperatingExpensesData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000027135Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ExpenseExample column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000027135Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ExpenseExampleNoRedemption column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000027135Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/BarChartData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000027135Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/PerformanceTableData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000027135Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ShareholderFeesData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011846Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/OperatingExpensesData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011846Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ExpenseExample column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011846Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ExpenseExampleNoRedemption column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011846Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/BarChartData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011846Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/PerformanceTableData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011846Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ShareholderFeesData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011850Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/OperatingExpensesData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011850Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ExpenseExample column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011850Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ExpenseExampleNoRedemption column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011850Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/BarChartData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011850Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/PerformanceTableData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011850Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ShareholderFeesData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011851Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/OperatingExpensesData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011851Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ExpenseExample column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011851Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ExpenseExampleNoRedemption column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011851Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/BarChartData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011851Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/PerformanceTableData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011851Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ShareholderFeesData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000064930Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/OperatingExpensesData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000064930Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ExpenseExample column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000064930Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/BarChartData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000064930Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/PerformanceTableData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000064930Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ShareholderFeesData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000043670Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/OperatingExpensesData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000043670Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ExpenseExample column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000043670Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/BarChartData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000043670Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/PerformanceTableData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000043670Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ShareholderFeesData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011842Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/OperatingExpensesData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011842Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ExpenseExample column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011842Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ExpenseExampleNoRedemption column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011842Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/BarChartData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011842Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/PerformanceTableData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011842Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ShareholderFeesData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011845Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/OperatingExpensesData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011845Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ExpenseExample column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011845Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ExpenseExampleNoRedemption column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011845Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/BarChartData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011845Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/PerformanceTableData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011845Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ShareholderFeesData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000082059Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/OperatingExpensesData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000082059Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ExpenseExample column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000082059Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ExpenseExampleNoRedemption column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000082059Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/BarChartData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000082059Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/PerformanceTableData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000082059Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ShareholderFeesData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000020097Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/OperatingExpensesData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000020097Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ExpenseExample column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000020097Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ExpenseExampleNoRedemption column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000020097Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/BarChartData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000020097Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/PerformanceTableData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000020097Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ShareholderFeesData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000043669Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/OperatingExpensesData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000043669Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ExpenseExample column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000043669Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/BarChartData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000043669Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/PerformanceTableData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000043669Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ShareholderFeesData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000000540Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/OperatingExpensesData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000000540Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ExpenseExample column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000000540Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ExpenseExampleNoRedemption column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000000540Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/BarChartData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000000540Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/PerformanceTableData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000000540Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ShareholderFeesData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011844Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/OperatingExpensesData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011844Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ExpenseExample column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011844Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ExpenseExampleNoRedemption column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011844Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/BarChartData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011844Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/PerformanceTableData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011844Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ShareholderFeesData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000025152Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/OperatingExpensesData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000025152Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ExpenseExample column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000025152Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ExpenseExampleNoRedemption column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000025152Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/BarChartData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000025152Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/PerformanceTableData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000025152Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ShareholderFeesData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011841Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/OperatingExpensesData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011841Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ExpenseExample column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011841Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ExpenseExampleNoRedemption column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011841Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/BarChartData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011841Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/PerformanceTableData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011841Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ShareholderFeesData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011843Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/OperatingExpensesData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011843Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ExpenseExample column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011843Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/BarChartData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011843Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/PerformanceTableData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011843Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ShareholderFeesData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011848Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/OperatingExpensesData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011848Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ExpenseExample column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011848Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/BarChartData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011848Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/PerformanceTableData column dei_DocumentInformationDocumentAxis compact tbit_RetailMember column dei_LegalEntityAxis compact tbit_S000011848Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ShareholderFeesData column dei_DocumentInformationDocumentAxis compact tbit_RetirementMember column dei_LegalEntityAxis compact tbit_S000012859Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/OperatingExpensesData column dei_DocumentInformationDocumentAxis compact tbit_RetirementMember column dei_LegalEntityAxis compact tbit_S000012859Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ExpenseExample column dei_DocumentInformationDocumentAxis compact tbit_RetirementMember column dei_LegalEntityAxis compact tbit_S000012859Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/BarChartData column dei_DocumentInformationDocumentAxis compact tbit_RetirementMember column dei_LegalEntityAxis compact tbit_S000012859Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/PerformanceTableData column dei_DocumentInformationDocumentAxis compact tbit_RetirementMember column dei_LegalEntityAxis compact tbit_S000012859Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

~ http://Thornburg.com/role/ShareholderFeesData column dei_DocumentInformationDocumentAxis compact tbit_RetirementMember column dei_LegalEntityAxis compact tbit_S000011849Member column rr_ProspectusShareClassAxis compact * row primary compact * ~

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