Mack Fuller

Mack Fuller is a managing director, senior portfolio manager, and head of Sustainable Investing at MetLife Investment Management (MIM). Mack joined MIM in December 2025, in connection with the acquisition of PineBridge Investments by MIM.

At PineBridge, Mack was responsible for sourcing, underwriting, executing, and monitoring investments for the firm’s middle market private credit business. As head of Sustainable Investing, he led the team’s development of sustainable investment strategies and ESG integration into credit processes and procedures. Mack has over 22 years of experience lending to and investing in leveraged loans and high-yield bonds issued by middle market companies and large corporates. Prior to PineBridge, Mack was a principal and senior research analyst at Blackstone Credit (f/k/a GSO Capital Partners), where he analyzed and evaluated primary and secondary fixed income investments. Prior to Blackstone, Mack worked at Callidus Capital Management, a portfolio company of Allied Capital, where he evaluated broadly syndicated loan and high-yield investment opportunities across multiple industries. Prior to that, Mack worked at JPMorgan Chase & Co. within the Middle Market Leverage Finance business.

Mack received a Bachelor’s in business administration with a major in business management and a minor in business law, magna cum laude from Pace University/Lubin School of Business, and a master’s in business administration with a finance concentration from Columbia Business School, where he attended as a Credit Suisse First Boston Fellow.