Thornburg Investment Income Builder Fund Class R3 (TIBRX) is an open-end mutual fund managed by Thornburg Investment Management that seeks to provide a high level of current income exceeding the average yield on U.S. stocks, with long-term capital appreciation as a secondary objective. The fund invests under normal conditions at least 80% of its assets in income-producing securities, including at least 50% in common stocks, and a broad range of bonds; its portfolio features a globally diversified mix of dividend-paying equities and fixed income instruments across sectors and regions, with exposure to both U.S. and non-U.S. markets. Available primarily to U.S. investors through retirement platforms, it offers quarterly distributions, with Class R3 shares featuring a net expense ratio of 1.54% and no front-end or deferred loads.
Offered within Thornburg Investment Management's multi-asset fund lineup alongside share classes such as A (TIBAX), C (TIBCX), I (TIBIX), and others, TIBRX belongs to the Morningstar Global Moderately Aggressive Allocation category and benchmarks against the Investment Income Builder Blended Index. Thornburg Investment Management, founded in 1982 and headquartered in Santa Fe, New Mexico, with additional offices in London and Hong Kong, manages approximately $46 billion in client assets and provides mutual funds, ETFs, closed-end funds, separate accounts, and UCITS funds to institutions, financial professionals, and investors worldwide. The Class R3 shares of the Investment Income Builder Fund were incepted on February 1, 2005, while the overall strategy traces back to 2003.
Recent strategic enhancements include the repositioning and renaming of the firm's UCITS version of the Investment Income Builder Fund to Thornburg Equity Income Builder Fund in 2025, emphasizing its global equity income focus while maintaining the core investment approach; this was accompanied by management fee reductions (e.g., from 0.80% to 0.65% on select classes) effective April 1, 2025, and reclassification of five UCITS funds, including this one, to Article 8 under EU SFDR for improved ESG integration. Thornburg also opened a London office in early 2025 and added key personnel such as Jon Dawson and Cornelia Sanders to bolster international operations. These changes reflect ongoing efforts to enhance accessibility, pricing competitiveness, and alignment with global client needs amid a portfolio net asset base exceeding $18 billion as of late 2025.