John Koudounis serves as the President and CEO of Calamos Investments, playing a pivotal role in enhancing the firm's strategic initiatives and business development. Under his leadership, the firm's AUM surged to over $40 billion, nearly tripling since he took the helm. Notably, he has overseen the launch of innovative products, including the world's first suite of downside-protected Bitcoin ETFs. 

Koudounis was appointed as the first CEO by the firm's founder, John P. Calamos, Sr., as part of a succession plan initiated in 2016. With over 37 years of experience in the financial services sector, he previously held the position of President and CEO at Mizuho Securities in the Americas, where he significantly expanded the firm's capital markets teams and enhanced profitability, client base, and product diversity, elevating Mizuho to a top-tier global investment bank. 

In addition to his corporate responsibilities, Koudounis is recognized for his thought leadership, frequently speaking at global conferences and appearing on major financial news platforms such as CNN, Fox Business, CNBC, Bloomberg TV, Yahoo Finance Live and many others. His insights are highly sought after in the financial community. 

Koudounis is committed to philanthropy, holding various board positions and engaging in community outreach. He founded the Chicago CEO COVID-19 Coalition in 2020 and is involved with several organizations including the Concordia Leadership Council, the SEAL Future Foundation, The Hellenic Initiative, and the Ecumenical Bartholomew Foundation. 

He holds a degree in International Diplomacy & Foreign Affairs and Economics from Brown University.