Dr. Stefan Bornheim

Driven by the belief that effective leadership is more than technical excellence, Dr. Stefan Bornheim founded TSBC, shaping its intellectual and strategic identity for over two decades. Before founding TSBC, he served as a manager at the Mitchell Madison Group, advising international corporations through transformation and growth. He completed a post-doctoral fellowship at UNC Chapel Hill and earned his doctorate at the University of St. Gallen, where he also taught leadership and organizational development — laying the foundations for TSBC’s “Value-Based Leadership beyond Meritocracy” philosophy. His research received support from the Swiss National Science Foundation, and he was elected to Alpha Sigma Nu, the American Jesuit Honor Society. His thinking bridges academic depth with executive practice and continues to define TSBC’s work today.

Frederik Sonner

For more than a decade, Frederik Sonner has advised TSBC clients on leadership within the context of executive enablement, meta-strategic challenges, and complex organizational dynamics. Before joining TSBC, he held a consulting role at the Jesuit Institute for Philosophy and Leadership in Munich. He studied philosophy and economics at the Jesuit University of Philosophy in Munich and at Fordham University in New York. In addition, he has contributed to TSBC’s thought leadership, including co-authoring insights in the firm’s published “Value-Based Leadership” work.

Dion Joannou

With more than three decades of leadership experience in technology, telecommunications, software, cybersecurity, and AI, Dion Joannou leads TSBC’s U.S. expansion and client engagements. As CEO, he guided multiple companies in the technology, consumer, and cleantech sectors through growth and transformation, including overseeing the acquisition of Accedian by Cisco in 2023. Earlier in his career, he spent 14 years at Nortel Networks — holding roles such as President North America, and Chief Strategy Officer — and later served in senior executive positions at Viavi (JDSU). Alongside his role at TSBC, he has advised leading private equity firms (including TowerBrook, Matlin Patterson, Investcorp, and BGP) and invests in high-growth start-ups across software, cyber, and medtech. Dion also serves on the boards of public and private companies.