Fund Evaluator:

Thornburg Investment Income Builder I Overview

Thornburg Investment Income Builder I (TIBIX) is an actively managed Allocation Global Moderately Aggressive Allocation fund. Thornburg launched the fund in 2003.

The investment seeks to provide a level of current income which exceeds the average yield on U.S. stocks; long-term capital appreciation is a secondary objective. The fund pursues its investment goals by investing in a broad range of income producing securities, primarily including stocks and bonds. It will under normal conditions invest at least 80% of its net assets, plus the amount of any borrowings for investment purposes, in income-producing securities, and at least 50% of its net assets, plus the amount of any borrowings for investment purposes, in common stocks.

About Thornburg Investment Income Builder I (TIBIX)

There are 3 members of the management team with an average tenure of 11.35 years: Brian McMahon (2002), Matt Burdett (2019), Christian Hoffmann (2023). Management tenure is more important for actively managed funds than passive index funds.

The fund has 2 primary benchmarks: MSCI World NR USD index with a weighting of 100% and Bloomberg US Agg Bond TR USD index with a weighting of 100%. Thornburg Investment Income Builder I has 333 securities in its portfolio. The top 10 holdings constitute 44.9% of the fund’s assets. The fund meets the SEC requirement of being classified as a diversified fund. The fund is not considered to have an ESG focus with its investment selection and management.

Thornburg Investment Income Builder I is part of the Allocation global asset class and is within the Allocation fund group. Thornburg Investment Income Builder I has 66.3% of its portfolio invested in foreign issues. The overall assets allocated to domestic stock is 21.6%. There is 64.7% allocated to foreign stock, and 0.6% is allocated to preferred stocks. The bond allocation as a percentage of total assets is 5.4% (3.8% domestic bond, 1.6% foreign bond and 0.0% convertible bond). Thornburg Investment Income Builder I has 7.6% of the portfolio in cash.

Assets Under Management

The fund has $15 billion in total assets, which is above the $1 billion average for the Global Moderately Aggressive Allocation category. Normally, lower assets under management translates to higher average expense ratios, and greater total assets are desired. However, for some investment categories, such as small-cap investing, it may be difficult for the manager to fully employ the desired active strategy if assets grow too large or too quickly.

TIBIX Performance and Fees

The expense ratio measures how much of a fund’s assets are used for administrative expenses and operating expenses, including adviser fees and fees for the transfer agent and custodial services. The Thornburg Investment Income Builder I expense ratio is high compared to funds in the Global Moderately Aggressive Allocation category. Thornburg Investment Income Builder I has an expense ratio of 0.91%, which is 9% lower than its category average, making the fund expense ratio grade a C. While it is difficult to predict returns, it is known that high annual expense ratios reduce your rate of return, and excessive fees are difficult to overcome. Active management normally comes with higher expense ratios than passive index management. Certain investment categories such as small company and foreign also normally have higher expense ratios. It is best to compare fund expense ratios against the category averages for meaningful assessments.

High portfolio turnover can translate to higher expenses and lower aftertax returns. A portfolio turnover rate cannot be currently calculated for Thornburg Investment Income Builder I. By way of comparison, the average portfolio turnover is 32% for the Global Moderately Aggressive Allocation category.

Recently, in the month of July 2026, Thornburg Investment Income Builder I returned 2.9%, which earned it a grade of A, as the Global Moderately Aggressive Allocation category had an average return of 0.2%. The letter grades of A, B, C, D and F are based upon relative rankings within the investment category. A grade of A, for example, would indicate that the return is in the highest 20% for that time period compared to all funds in that category.

Thornburg Investment Income Builder I has a trailing yield of 3.30%, which is above the 1.98% category average. The fund normally distributes its income quarterly and its capital gains annually.

It’s natural to seek the best-performing investments, but you must consider the relationship between risk and return and the impact of costs and taxes on your realized returns.

Thornburg Investment Income Builder I Grades

Year to date, the fund has returned 19.5%, 9.7 percentage points better than the category, which translates into a grade of A. The fund has returned 34.7% over the past year (grade of A), 25.0% over the past three years (grade of A) and 16.7% per year over the past five years (grade of A) and 12.4% per year over the past 10 years (grade of A).

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