Share Class

AVERAGE ANNUAL TOTAL RETURNS

A Shares (Incep. 2/1/2007) YTD 1-YR 3-YR 5-YR 10-YR INCEPTION
TIGAX without sales charge4.12%15.05%8.74%7.93%7.22%8.12%
TIGAX with sales charge-0.57%9.88%7.08%6.93%6.73%7.68%
Benchmark (Since 2/1/2007)
MSCI AC World ex-U.S. Growth Index-0.69%11.77%6.20%6.64%2.41%3.62%
C Shares (Incep. 2/1/2007) YTD 1-YR 3-YR 5-YR 10-YR INCEPTION
TIGCX without sales charge3.79%14.19%7.90%7.12%6.48%7.36%
TIGCX with sales charge2.79%13.19%7.90%7.12%6.48%7.36%
Benchmark (Since 2/1/2007)
MSCI AC World ex-U.S. Growth Index-0.69%11.77%6.20%6.64%2.41%3.62%
I Shares (Incep. 2/1/2007) YTD 1-YR 3-YR 5-YR 10-YR INCEPTION
TINGX4.25%15.45%9.16%8.35%7.74%8.66%
Benchmark (Since 2/1/2007)
MSCI AC World ex-U.S. Growth Index-0.69%11.77%6.20%6.64%2.41%3.62%
R3 Shares (Incep. 2/1/2008) YTD 1-YR 3-YR 5-YR 10-YR INCEPTION*
TIGVX4.02%14.85%8.61%7.80%7.19%8.10%
Benchmark (Since 2/1/2007)
MSCI AC World ex-U.S. Growth Index-0.69%11.77%6.20%6.64%2.41%3.62%
R4 Shares (Incep. 2/1/2008) YTD 1-YR 3-YR 5-YR 10-YR INCEPTION*
TINVX4.10%14.96%8.71%7.92%7.30%8.21%
Benchmark (Since 2/1/2007)
MSCI AC World ex-U.S. Growth Index-0.69%11.77%6.20%6.64%2.41%3.62%
R5 Shares (Incep. 2/1/2008) YTD 1-YR 3-YR 5-YR 10-YR INCEPTION*
TINFX4.24%15.43%9.17%8.35%7.73%8.65%
Benchmark (Since 2/1/2007)
MSCI AC World ex-U.S. Growth Index-0.69%11.77%6.20%6.64%2.41%3.62%
R6 Shares (Incep. 2/1/2013) YTD 1-YR 3-YR 5-YR 10-YR INCEPTION*
THGIX4.31%15.56%9.28%8.45%7.76%8.67%
Benchmark (Since 2/1/2007)
MSCI AC World ex-U.S. Growth Index-0.69%11.77%6.20%6.64%2.41%3.62%
A Shares (Incep. 2/1/2007) YTD 1-YR 3-YR 5-YR 10-YR INCEPTION
TIGAX without sales charge1.87%23.58%9.65%8.30%7.48%8.04%
TIGAX with sales charge-2.71%18.01%7.98%7.31%6.99%7.59%
Benchmark (Since 2/1/2007)
MSCI AC World ex-U.S. Growth Index-0.87%19.92%7.28%6.84%3.25%3.66%
C Shares (Incep. 2/1/2007) YTD 1-YR 3-YR 5-YR 10-YR INCEPTION
TIGCX without sales charge1.67%22.65%8.82%7.48%6.72%7.28%
TIGCX with sales charge0.67%21.65%8.82%7.48%6.72%7.28%
Benchmark (Since 2/1/2007)
MSCI AC World ex-U.S. Growth Index-0.87%19.92%7.28%6.84%3.25%3.66%
I Shares (Incep. 2/1/2007) YTD 1-YR 3-YR 5-YR 10-YR INCEPTION
TINGX1.98%24.08%10.11%8.73%8.00%8.58%
Benchmark (Since 2/1/2007)
MSCI AC World ex-U.S. Growth Index-0.87%19.92%7.28%6.84%3.25%3.66%
R3 Shares (Incep. 2/1/2008) YTD 1-YR 3-YR 5-YR 10-YR INCEPTION*
TIGVX1.80%23.43%9.54%8.18%7.45%8.02%
Benchmark (Since 2/1/2007)
MSCI AC World ex-U.S. Growth Index-0.87%19.92%7.28%6.84%3.25%3.66%
R4 Shares (Incep. 2/1/2008) YTD 1-YR 3-YR 5-YR 10-YR INCEPTION*
TINVX1.88%23.59%9.65%8.29%7.56%8.13%
Benchmark (Since 2/1/2007)
MSCI AC World ex-U.S. Growth Index-0.87%19.92%7.28%6.84%3.25%3.66%
R5 Shares (Incep. 2/1/2008) YTD 1-YR 3-YR 5-YR 10-YR INCEPTION*
TINFX1.93%24.05%10.10%8.72%8.00%8.57%
Benchmark (Since 2/1/2007)
MSCI AC World ex-U.S. Growth Index-0.87%19.92%7.28%6.84%3.25%3.66%
R6 Shares (Incep. 2/1/2013) YTD 1-YR 3-YR 5-YR 10-YR INCEPTION*
THGIX2.01%24.23%10.23%8.83%8.03%8.58%
Benchmark (Since 2/1/2007)
MSCI AC World ex-U.S. Growth Index-0.87%19.92%7.28%6.84%3.25%3.66%

Returns for less than one year are not annualized.
Source: Confluence

Returns for less than one year are not annualized.
Source: Confluence

Returns for less than one year are not annualized.
Source: Confluence

* Since 2/1/2007.
Prior to inception of this share class, performance is hypothetical and was calculated from actual returns of an earlier share class adjusted for the expenses of the newer share class.
Returns for less than one year are not annualized.
Source: Confluence

* Since 2/1/2007.
Prior to inception of this share class, performance is hypothetical and was calculated from actual returns of an earlier share class adjusted for the expenses of the newer share class.
Returns for less than one year are not annualized.
Source: Confluence

* Since 2/1/2007.
Prior to inception of this share class, performance is hypothetical and was calculated from actual returns of an earlier share class adjusted for the expenses of the newer share class.
Returns for less than one year are not annualized.
Source: Confluence

* Since 2/1/2007.
Prior to inception of this share class, performance is hypothetical and was calculated from actual returns of an earlier share class adjusted for the expenses of the newer share class.
Returns for less than one year are not annualized.
Source: Confluence

Performance data shown represents past performance and is no guarantee of future results. Investment return and principal value will fluctuate so shares, when redeemed, may be worth more or less than their original cost. Current performance may be lower or higher than quoted.

The maximum sales charge for the Fund’s A shares is 4.50%.

C shares include a 1% contingent deferred sales charge (CDSC) for the first year only.

There is no up-front sales charge for class I shares.

There is no up-front sales charge for class R shares.

FUND OPERATING EXPENSES — Class A Shares

Gross Annual Operating Expenses (as reported in the most recent Prospectus)1.39%
Actual Annual Operating Expenses (fiscal year to date, as of 3/31/2018)1.35%

Expense Ratios – Expressed as a percentage of total fund assets and include management fees and operating costs. Expense ratios fluctuate over time and the expense ratio in the prospectus may differ from the actual expense ratio. The fund's total return includes the deduction of expenses.

For more detailed information on fund expenses, please see the fund's prospectus.

FUND OPERATING EXPENSES — Class C Shares

Gross Annual Operating Expenses (as reported in the most recent Prospectus)2.12%
Actual Annual Operating Expenses (fiscal year to date, as of 3/31/2018)2.10%

Expense Ratios – Expressed as a percentage of total fund assets and include management fees and operating costs. Expense ratios fluctuate over time and the expense ratio in the prospectus may differ from the actual expense ratio. The fund's total return includes the deduction of expenses.

For more detailed information on fund expenses, please see the fund's prospectus.

FUND OPERATING EXPENSES — Class I Shares

Gross Annual Operating Expenses (as reported in the most recent Prospectus)1.06%
Net Annual Operating Expenses (as reported in the most recent Prospectus)0.99%
Actual Annual Operating Expenses (fiscal year to date, as of 3/31/2018)0.99%

Thornburg Investment Management and/or Thornburg Securities Corporation have contractually agreed to waive fees and reimburse expenses through at least June 15, 2019 so that actual expenses do not exceed the net expense ratio above.

Expense Ratios – Expressed as a percentage of total fund assets and include management fees and operating costs. Expense ratios fluctuate over time and the expense ratio in the prospectus may differ from the actual expense ratio. The fund's total return includes the deduction of expenses.

For more detailed information on fund expenses, please see the fund's prospectus.

FUND OPERATING EXPENSES — Class R3 Shares

Gross Annual Operating Expenses (as reported in the most recent Prospectus)2.04%
Net Annual Operating Expenses (as reported in the most recent Prospectus)1.50%
Actual Annual Operating Expenses (fiscal year to date, as of 3/31/2018)1.50%

Thornburg Investment Management and/or Thornburg Securities Corporation have contractually agreed to waive fees and reimburse expenses through at least June 15, 2019 so that actual expenses do not exceed the net expense ratio above.

Expense Ratios – Expressed as a percentage of total fund assets and include management fees and operating costs. Expense ratios fluctuate over time and the expense ratio in the prospectus may differ from the actual expense ratio. The fund's total return includes the deduction of expenses.

For more detailed information on fund expenses, please see the fund's prospectus.

FUND OPERATING EXPENSES — Class R4 Shares

Gross Annual Operating Expenses (as reported in the most recent Prospectus)1.80%
Net Annual Operating Expenses (as reported in the most recent Prospectus)1.40%
Actual Annual Operating Expenses (fiscal year to date, as of 3/31/2018)1.40%

Thornburg Investment Management and/or Thornburg Securities Corporation have contractually agreed to waive fees and reimburse expenses through at least June 15, 2019 so that actual expenses do not exceed the net expense ratio above.

Expense Ratios – Expressed as a percentage of total fund assets and include management fees and operating costs. Expense ratios fluctuate over time and the expense ratio in the prospectus may differ from the actual expense ratio. The fund's total return includes the deduction of expenses.

For more detailed information on fund expenses, please see the fund's prospectus.

FUND OPERATING EXPENSES — Class R5 Shares

Gross Annual Operating Expenses (as reported in the most recent Prospectus)1.31%
Net Annual Operating Expenses (as reported in the most recent Prospectus)0.99%
Actual Annual Operating Expenses (fiscal year to date, as of 3/31/2018)0.99%

Thornburg Investment Management and/or Thornburg Securities Corporation have contractually agreed to waive fees and reimburse expenses through at least June 15, 2019 so that actual expenses do not exceed the net expense ratio above.

Expense Ratios – Expressed as a percentage of total fund assets and include management fees and operating costs. Expense ratios fluctuate over time and the expense ratio in the prospectus may differ from the actual expense ratio. The fund's total return includes the deduction of expenses.

For more detailed information on fund expenses, please see the fund's prospectus.

FUND OPERATING EXPENSES — Class R6 Shares

Gross Annual Operating Expenses (as reported in the most recent Prospectus)1.06%
Net Annual Operating Expenses (as reported in the most recent Prospectus)0.89%
Actual Annual Operating Expenses (fiscal year to date, as of 3/31/2018)0.89%

Thornburg Investment Management and/or Thornburg Securities Corporation have contractually agreed to waive fees and reimburse expenses through at least June 15, 2019 so that actual expenses do not exceed the net expense ratio above.

Expense Ratios – Expressed as a percentage of total fund assets and include management fees and operating costs. Expense ratios fluctuate over time and the expense ratio in the prospectus may differ from the actual expense ratio. The fund's total return includes the deduction of expenses.

For more detailed information on fund expenses, please see the fund's prospectus.

MORNINGSTAR RATING

Overall Morningstar Rating among 108 Foreign Small/Mid Growth funds, based on risk-adjusted returns for class A shares, using a weighted average of the fund's three-, five- and ten-year ratings: respectively, 2 stars, 2 stars and 4 stars among 108, 103 and 63 funds, as of 5/31/2018.

Additional Rating and Ranking Information

To determine a fund's Morningstar Rating™, funds and other managed products with at least a three-year history are ranked in their categories by their Morningstar Risk-Adjusted Return scores. The top 10% receive 5 stars; the next 22.5%, 4 stars; the middle 35%, 3 stars; the next 22.5%, 2 stars; and the bottom 10% receive 1 star. The Risk-Adjusted Return accounts for variation in a managed product's monthly excess performance (excluding sales charges), placing more emphasis on downward variations and rewarding consistent performance. Other share classes may have different performance characteristics. © 2018 Morningstar, Inc. All Rights Reserved. The information contained herein: (1) is proprietary to Morningstar and/or its content providers; (2) may not be copied or distributed; and (3) is not warranted to be accurate, complete or timely. Neither Morningstar nor its content providers are responsible for any damages or losses arising from any use of this information. Past performance is no guarantee of future results.

MORNINGSTAR RATING

Overall Morningstar Rating among 108 Foreign Small/Mid Growth funds, based on risk-adjusted returns for class C shares, using a weighted average of the fund's three-, five- and ten-year ratings: respectively, 2 stars, 1 star and 4 stars among 108, 103 and 63 funds, as of 5/31/2018.

Additional Rating and Ranking Information

To determine a fund's Morningstar Rating™, funds and other managed products with at least a three-year history are ranked in their categories by their Morningstar Risk-Adjusted Return scores. The top 10% receive 5 stars; the next 22.5%, 4 stars; the middle 35%, 3 stars; the next 22.5%, 2 stars; and the bottom 10% receive 1 star. The Risk-Adjusted Return accounts for variation in a managed product's monthly excess performance (excluding sales charges), placing more emphasis on downward variations and rewarding consistent performance. Other share classes may have different performance characteristics. © 2018 Morningstar, Inc. All Rights Reserved. The information contained herein: (1) is proprietary to Morningstar and/or its content providers; (2) may not be copied or distributed; and (3) is not warranted to be accurate, complete or timely. Neither Morningstar nor its content providers are responsible for any damages or losses arising from any use of this information. Past performance is no guarantee of future results.

MORNINGSTAR RATING

Overall Morningstar Rating among 108 Foreign Small/Mid Growth funds, based on risk-adjusted returns for class I shares, using a weighted average of the fund's three-, five- and ten-year ratings: respectively, 2 stars, 2 stars and 5 stars among 108, 103 and 63 funds, as of 5/31/2018.

Additional Rating and Ranking Information

To determine a fund's Morningstar Rating™, funds and other managed products with at least a three-year history are ranked in their categories by their Morningstar Risk-Adjusted Return scores. The top 10% receive 5 stars; the next 22.5%, 4 stars; the middle 35%, 3 stars; the next 22.5%, 2 stars; and the bottom 10% receive 1 star. The Risk-Adjusted Return accounts for variation in a managed product's monthly excess performance (excluding sales charges), placing more emphasis on downward variations and rewarding consistent performance. Other share classes may have different performance characteristics. © 2018 Morningstar, Inc. All Rights Reserved. The information contained herein: (1) is proprietary to Morningstar and/or its content providers; (2) may not be copied or distributed; and (3) is not warranted to be accurate, complete or timely. Neither Morningstar nor its content providers are responsible for any damages or losses arising from any use of this information. Past performance is no guarantee of future results.

MORNINGSTAR RATING

Overall Morningstar Rating among 108 Foreign Small/Mid Growth funds, based on risk-adjusted returns for class R3 shares, using a weighted average of the fund's three-, five- and ten-year ratings: respectively, 2 stars, 2 stars and 4 stars among 108, 103 and 63 funds, as of 5/31/2018.

Additional Rating and Ranking Information

To determine a fund's Morningstar Rating™, funds and other managed products with at least a three-year history are ranked in their categories by their Morningstar Risk-Adjusted Return scores. The top 10% receive 5 stars; the next 22.5%, 4 stars; the middle 35%, 3 stars; the next 22.5%, 2 stars; and the bottom 10% receive 1 star. The Risk-Adjusted Return accounts for variation in a managed product's monthly excess performance (excluding sales charges), placing more emphasis on downward variations and rewarding consistent performance. Other share classes may have different performance characteristics. © 2018 Morningstar, Inc. All Rights Reserved. The information contained herein: (1) is proprietary to Morningstar and/or its content providers; (2) may not be copied or distributed; and (3) is not warranted to be accurate, complete or timely. Neither Morningstar nor its content providers are responsible for any damages or losses arising from any use of this information. Past performance is no guarantee of future results.

MORNINGSTAR RATING

Overall Morningstar Rating among 108 Foreign Small/Mid Growth funds, based on risk-adjusted returns for class R4 shares, using a weighted average of the fund's three-, five- and ten-year ratings: respectively, 2 stars, 2 stars and 4 stars among 108, 103 and 63 funds, as of 5/31/2018.

Additional Rating and Ranking Information

To determine a fund's Morningstar Rating™, funds and other managed products with at least a three-year history are ranked in their categories by their Morningstar Risk-Adjusted Return scores. The top 10% receive 5 stars; the next 22.5%, 4 stars; the middle 35%, 3 stars; the next 22.5%, 2 stars; and the bottom 10% receive 1 star. The Risk-Adjusted Return accounts for variation in a managed product's monthly excess performance (excluding sales charges), placing more emphasis on downward variations and rewarding consistent performance. Other share classes may have different performance characteristics. © 2018 Morningstar, Inc. All Rights Reserved. The information contained herein: (1) is proprietary to Morningstar and/or its content providers; (2) may not be copied or distributed; and (3) is not warranted to be accurate, complete or timely. Neither Morningstar nor its content providers are responsible for any damages or losses arising from any use of this information. Past performance is no guarantee of future results.

MORNINGSTAR RATING

Overall Morningstar Rating among 108 Foreign Small/Mid Growth funds, based on risk-adjusted returns for class R5 shares, using a weighted average of the fund's three-, five- and ten-year ratings: respectively, 2 stars, 2 stars and 5 stars among 108, 103 and 63 funds, as of 5/31/2018.

Additional Rating and Ranking Information

To determine a fund's Morningstar Rating™, funds and other managed products with at least a three-year history are ranked in their categories by their Morningstar Risk-Adjusted Return scores. The top 10% receive 5 stars; the next 22.5%, 4 stars; the middle 35%, 3 stars; the next 22.5%, 2 stars; and the bottom 10% receive 1 star. The Risk-Adjusted Return accounts for variation in a managed product's monthly excess performance (excluding sales charges), placing more emphasis on downward variations and rewarding consistent performance. Other share classes may have different performance characteristics. © 2018 Morningstar, Inc. All Rights Reserved. The information contained herein: (1) is proprietary to Morningstar and/or its content providers; (2) may not be copied or distributed; and (3) is not warranted to be accurate, complete or timely. Neither Morningstar nor its content providers are responsible for any damages or losses arising from any use of this information. Past performance is no guarantee of future results.

MORNINGSTAR RATING

Overall Morningstar Rating among 108 Foreign Small/Mid Growth funds, based on risk-adjusted returns for class R6 shares, using a weighted average of the fund's three-, five- and ten-year ratings: respectively, 3 stars, 2 stars and 5 stars among 108, 103 and 63 funds, as of 5/31/2018.

Additional Rating and Ranking Information

To determine a fund's Morningstar Rating™, funds and other managed products with at least a three-year history are ranked in their categories by their Morningstar Risk-Adjusted Return scores. The top 10% receive 5 stars; the next 22.5%, 4 stars; the middle 35%, 3 stars; the next 22.5%, 2 stars; and the bottom 10% receive 1 star. The Risk-Adjusted Return accounts for variation in a managed product's monthly excess performance (excluding sales charges), placing more emphasis on downward variations and rewarding consistent performance. Other share classes may have different performance characteristics. © 2018 Morningstar, Inc. All Rights Reserved. The information contained herein: (1) is proprietary to Morningstar and/or its content providers; (2) may not be copied or distributed; and (3) is not warranted to be accurate, complete or timely. Neither Morningstar nor its content providers are responsible for any damages or losses arising from any use of this information. Past performance is no guarantee of future results.

LIPPER LEADER as of 3/31/2018 — Class A Shares

Total Return among 400 funds
Consistent Return among 400 funds
In the International Multi-Cap Growth category

The Fund rated a 5 for the three-, five-, and ten-year periods for Total Return among 400, 361 and 249 funds, respectively. The Fund rated a 5 for the three-year period, a 4 for the five-year period and a 5 for the ten-year period for Consistent Return among 400, 361 and 249 funds, respectively.

Additional Rating and Ranking Information

Lipper ratings for Total Return reflect funds’ historical total return performance (before sales charge) relative to peers. Lipper ratings for Consistent Return reflect funds’ historical risk-adjusted returns (before sales charge), adjusted for volatility, relative to peers. The ratings are subject to change every month and are based on an equal-weighted average of percentile ranks for each metric over three-, five-, and ten-year periods (if applicable). The highest 20% of funds in each peer group are named Lipper Leader, or a score of 5, the next 20% receive a score of 4, the middle 20% are scored 3, the next 20% are scored 2, and the lowest 20% are scored 1. Lipper ratings are not intended to predict future results, and Lipper does not guarantee the accuracy of this information. More information is available at www.lipperweb.com. Thomson Reuters Copyright 2018, All Rights Reserved.

LIPPER LEADER as of 3/31/2018 — Class C Shares

Total Return among 400 funds
In the International Multi-Cap Growth category

The Fund rated a 5 for the three-year period, a 4 for the five-year period and a 5 for the ten-year period for Total Return among 400, 361 and 249 funds, respectively.

Additional Rating and Ranking Information

Lipper ratings for Total Return reflect funds’ historical total return performance (before sales charge) relative to peers. The ratings are subject to change every month and are based on an equal-weighted average of percentile ranks for each metric over three-, five-, and ten-year periods (if applicable). The highest 20% of funds in each peer group are named Lipper Leader, or a score of 5, the next 20% receive a score of 4, the middle 20% are scored 3, the next 20% are scored 2, and the lowest 20% are scored 1. Lipper ratings are not intended to predict future results, and Lipper does not guarantee the accuracy of this information. More information is available at www.lipperweb.com. Thomson Reuters Copyright 2018, All Rights Reserved.

LIPPER LEADER as of 3/31/2018 — Class I Shares

Total Return among 400 funds
Consistent Return among 400 funds
In the International Multi-Cap Growth category

The Fund rated a 5 for the three-, five-, and ten-year periods for Total Return among 400, 361 and 249 funds, respectively. The Fund rated a 5 for the three-, five-, and ten-year periods for Consistent Return among 400, 361 and 249 funds, respectively.

Additional Rating and Ranking Information

Lipper ratings for Total Return reflect funds’ historical total return performance (before sales charge) relative to peers. Lipper ratings for Consistent Return reflect funds’ historical risk-adjusted returns (before sales charge), adjusted for volatility, relative to peers. The ratings are subject to change every month and are based on an equal-weighted average of percentile ranks for each metric over three-, five-, and ten-year periods (if applicable). The highest 20% of funds in each peer group are named Lipper Leader, or a score of 5, the next 20% receive a score of 4, the middle 20% are scored 3, the next 20% are scored 2, and the lowest 20% are scored 1. Lipper ratings are not intended to predict future results, and Lipper does not guarantee the accuracy of this information. More information is available at www.lipperweb.com. Thomson Reuters Copyright 2018, All Rights Reserved.

LIPPER LEADER as of 3/31/2018 — Class R3 Shares

Total Return among 400 funds
Consistent Return among 400 funds
In the International Multi-Cap Growth category

The Fund rated a 5 for the three-year period, a 4 for the five-year period and a 5 for the ten-year period for Total Return among 400, 361 and 249 funds, respectively. The Fund rated a 5 for the three-year period, a 4 for the five-year period and a 5 for the ten-year period for Consistent Return among 400, 361 and 249 funds, respectively.

Additional Rating and Ranking Information

Lipper ratings for Total Return reflect funds’ historical total return performance (before sales charge) relative to peers. Lipper ratings for Consistent Return reflect funds’ historical risk-adjusted returns (before sales charge), adjusted for volatility, relative to peers. The ratings are subject to change every month and are based on an equal-weighted average of percentile ranks for each metric over three-, five-, and ten-year periods (if applicable). The highest 20% of funds in each peer group are named Lipper Leader, or a score of 5, the next 20% receive a score of 4, the middle 20% are scored 3, the next 20% are scored 2, and the lowest 20% are scored 1. Lipper ratings are not intended to predict future results, and Lipper does not guarantee the accuracy of this information. More information is available at www.lipperweb.com. Thomson Reuters Copyright 2018, All Rights Reserved.

LIPPER LEADER as of 3/31/2018 — Class R4 Shares

Total Return among 400 funds
Consistent Return among 400 funds
In the International Multi-Cap Growth category

The Fund rated a 5 for the three-, five-, and ten-year periods for Total Return among 400, 361 and 249 funds, respectively. The Fund rated a 5 for the three-year period, a 4 for the five-year period and a 5 for the ten-year period for Consistent Return among 400, 361 and 249 funds, respectively.

Additional Rating and Ranking Information

Lipper ratings for Total Return reflect funds’ historical total return performance (before sales charge) relative to peers. Lipper ratings for Consistent Return reflect funds’ historical risk-adjusted returns (before sales charge), adjusted for volatility, relative to peers. The ratings are subject to change every month and are based on an equal-weighted average of percentile ranks for each metric over three-, five-, and ten-year periods (if applicable). The highest 20% of funds in each peer group are named Lipper Leader, or a score of 5, the next 20% receive a score of 4, the middle 20% are scored 3, the next 20% are scored 2, and the lowest 20% are scored 1. Lipper ratings are not intended to predict future results, and Lipper does not guarantee the accuracy of this information. More information is available at www.lipperweb.com. Thomson Reuters Copyright 2018, All Rights Reserved.

LIPPER LEADER as of 3/31/2018 — Class R5 Shares

Total Return among 400 funds
Consistent Return among 400 funds
In the International Multi-Cap Growth category

The Fund rated a 5 for the three-, five-, and ten-year periods for Total Return among 400, 361 and 249 funds, respectively. The Fund rated a 5 for the three-year period, a 4 for the five-year period and a 5 for the ten-year period for Consistent Return among 400, 361 and 249 funds, respectively.

Additional Rating and Ranking Information

Lipper ratings for Total Return reflect funds’ historical total return performance (before sales charge) relative to peers. Lipper ratings for Consistent Return reflect funds’ historical risk-adjusted returns (before sales charge), adjusted for volatility, relative to peers. The ratings are subject to change every month and are based on an equal-weighted average of percentile ranks for each metric over three-, five-, and ten-year periods (if applicable). The highest 20% of funds in each peer group are named Lipper Leader, or a score of 5, the next 20% receive a score of 4, the middle 20% are scored 3, the next 20% are scored 2, and the lowest 20% are scored 1. Lipper ratings are not intended to predict future results, and Lipper does not guarantee the accuracy of this information. More information is available at www.lipperweb.com. Thomson Reuters Copyright 2018, All Rights Reserved.

LIPPER LEADER as of 3/31/2018 — Class R6 Shares

Total Return among 400 funds
Consistent Return among 400 funds
In the International Multi-Cap Growth category

The Fund rated a 5 for the three- and five-year periods for Total Return among 400 and 361 funds, respectively. The Fund rated a 5 for the three- and five-year periods for Consistent Return among 400 and 361 funds, respectively.

Additional Rating and Ranking Information

Lipper ratings for Total Return reflect funds’ historical total return performance (before sales charge) relative to peers. Lipper ratings for Consistent Return reflect funds’ historical risk-adjusted returns (before sales charge), adjusted for volatility, relative to peers. The ratings are subject to change every month and are based on an equal-weighted average of percentile ranks for each metric over three-, five-, and ten-year periods (if applicable). The highest 20% of funds in each peer group are named Lipper Leader, or a score of 5, the next 20% receive a score of 4, the middle 20% are scored 3, the next 20% are scored 2, and the lowest 20% are scored 1. Lipper ratings are not intended to predict future results, and Lipper does not guarantee the accuracy of this information. More information is available at www.lipperweb.com. Thomson Reuters Copyright 2018, All Rights Reserved.

Dividends and Capital Gains — Class A Shares

Dividend (December 2017)None Paid
Capital Gains for 2017 paid Nov 17, 2017
     Short-Term (per share)$0.05081
     Long-Term (per share)$0.76081
     Total (per share)$0.81162

Dividends and Capital Gains — Class C Shares

Dividend (December 2017)None Paid
Capital Gains for 2017 paid Nov 17, 2017
     Short-Term (per share)$0.05081
     Long-Term (per share)$0.76081
     Total (per share)$0.81162

Dividends and Capital Gains — Class I Shares

Dividend (December 2017)None Paid
Capital Gains for 2017 paid Nov 17, 2017
     Short-Term (per share)$0.05081
     Long-Term (per share)$0.76081
     Total (per share)$0.81162

Dividends and Capital Gains — Class R3 Shares

Dividend (December 2017)None Paid
Capital Gains for 2017 paid Nov 17, 2017
     Short-Term (per share)$0.05081
     Long-Term (per share)$0.76081
     Total (per share)$0.81162

Dividends and Capital Gains — Class R4 Shares

Dividend (December 2017)None Paid
Capital Gains for 2017 paid Nov 17, 2017
     Short-Term (per share)$0.05081
     Long-Term (per share)$0.76081
     Total (per share)$0.81162

Dividends and Capital Gains — Class R5 Shares

Dividend (December 2017)None Paid
Capital Gains for 2017 paid Nov 17, 2017
     Short-Term (per share)$0.05081
     Long-Term (per share)$0.76081
     Total (per share)$0.81162

Dividends and Capital Gains — Class R6 Shares

Dividend (December 2017)None Paid
Capital Gains for 2017 paid Nov 17, 2017
     Short-Term (per share)$0.05081
     Long-Term (per share)$0.76081
     Total (per share)$0.81162

HYPOTHETICAL GROWTH OF $10,000 as of 5/31/2018(Thornburg International Growth Fund vs. MSCI AC World ex-U.S. Growth Index)

  • A shares with sales charge$23,127
  • MSCI AC World ex-U.S. Growth Index$14,964
The Hypothetical Growth of $10,000 graph compares a hypothetical $10,000 investment in the Fund to the performance of the Index for the stated time period. Returns reflect reinvestment of dividends and capital gains, if any, as well as all fees and expenses.

HYPOTHETICAL GROWTH OF $10,000 as of 5/31/2018(Thornburg International Growth Fund vs. MSCI AC World ex-U.S. Growth Index)

  • C shares$22,357
  • MSCI AC World ex-U.S. Growth Index$14,964
The Hypothetical Growth of $10,000 graph compares a hypothetical $10,000 investment in the Fund to the performance of the Index for the stated time period. Returns reflect reinvestment of dividends and capital gains, if any, as well as all fees and expenses.

HYPOTHETICAL GROWTH OF $10,000 as of 5/31/2018(Thornburg International Growth Fund vs. MSCI AC World ex-U.S. Growth Index)

  • I shares$25,611
  • MSCI AC World ex-U.S. Growth Index$14,964
The Hypothetical Growth of $10,000 graph compares a hypothetical $10,000 investment in the Fund to the performance of the Index for the stated time period. Returns reflect reinvestment of dividends and capital gains, if any, as well as all fees and expenses.

HYPOTHETICAL GROWTH OF $10,000 as of 5/31/2018(Thornburg International Growth Fund vs. MSCI AC World ex-U.S. Growth Index)

  • R3 shares$24,172
  • MSCI AC World ex-U.S. Growth Index$14,964
The Hypothetical Growth of $10,000 graph compares a hypothetical $10,000 investment in the Fund to the performance of the Index for the stated time period. Returns reflect reinvestment of dividends and capital gains, if any, as well as all fees and expenses.

Prior to inception of this share class, performance is hypothetical and was calculated from actual returns of the class A shares adjusted for the expenses of the newer share class.

HYPOTHETICAL GROWTH OF $10,000 as of 5/31/2018(Thornburg International Growth Fund vs. MSCI AC World ex-U.S. Growth Index)

  • R4 shares$24,450
  • MSCI AC World ex-U.S. Growth Index$14,964
The Hypothetical Growth of $10,000 graph compares a hypothetical $10,000 investment in the Fund to the performance of the Index for the stated time period. Returns reflect reinvestment of dividends and capital gains, if any, as well as all fees and expenses.

Prior to inception of this share class, performance is hypothetical and was calculated from actual returns of the class A shares adjusted for the expenses of the newer share class.

HYPOTHETICAL GROWTH OF $10,000 as of 5/31/2018(Thornburg International Growth Fund vs. MSCI AC World ex-U.S. Growth Index)

  • R5 shares$25,596
  • MSCI AC World ex-U.S. Growth Index$14,964
The Hypothetical Growth of $10,000 graph compares a hypothetical $10,000 investment in the Fund to the performance of the Index for the stated time period. Returns reflect reinvestment of dividends and capital gains, if any, as well as all fees and expenses.

Prior to inception of this share class, performance is hypothetical and was calculated from actual returns of the class A shares adjusted for the expenses of the newer share class.

HYPOTHETICAL GROWTH OF $10,000 as of 5/31/2018(Thornburg International Growth Fund vs. MSCI AC World ex-U.S. Growth Index)

  • R6 shares$25,634
  • MSCI AC World ex-U.S. Growth Index$14,964
The Hypothetical Growth of $10,000 graph compares a hypothetical $10,000 investment in the Fund to the performance of the Index for the stated time period. Returns reflect reinvestment of dividends and capital gains, if any, as well as all fees and expenses.

Prior to inception of this share class, performance is hypothetical and was calculated from actual returns of the class A shares adjusted for the expenses of the newer share class.

Important Information
Before investing, carefully consider the Fund’s investment goals, risks, charges, and expenses. For a prospectus or summary prospectus containing this and other information, contact your financial advisor or visit thornburg.com. Read them carefully before investing.

Investments carry risks, including possible loss of principal. Additional risks may be associated with investments outside the United States, especially in emerging markets, including currency fluctuations, illiquidity, volatility, and political and economic risks. Investments in small- and mid-capitalization companies may increase the risk of greater price fluctuations. Investments in the Fund are not FDIC insured, nor are they bank deposits or guaranteed by a bank or any other entity.

The performance of any index is not indicative of the performance of any particular investment. Unless otherwise noted, index returns reflect the reinvestment of income dividends and capital gains, if any, but do not reflect fees, brokerage commissions or other expenses of investing. Investors may not make direct investments into any index.

Diversification does not assure or guarantee better performance and cannot eliminate the risk of investment losses.

Funds invested in a limited number of holdings may expose an investor to greater volatility.

Class R shares are limited to retirement platforms only.

Class I shares may not be available to all investors. Minimum investments for the I share class may be higher than those for other classes.

There is no guarantee that the Fund will meet its investment objectives.

Please see our glossary for a definition of terms.

Thornburg mutual funds are distributed by Thornburg Securities Corporation.

Thornburg Investment Management, Inc. mutual funds are sold through investment professionals including investment advisors, brokerage firms, bank trust departments, trust companies and certain other financial intermediaries. Thornburg Securities Corporation (TSC) does not act as broker of record for investors.