His practice focuses on negotiating complex purchase agreements and guiding clients through all stages of joint venture formation—from initial term sheet and joint venture contract negotiations to ongoing governance advice, including coordination with shareholders and investors, shareholder meetings, and management decision-making. His recent matters include the energy, regulated infrastructure, and industrial sectors. He also counsels on corporate reorganizations, including the outsourcing and relocation of business units, often as part of strategic realignments or in preparation for third‑party sales.

Beyond his corporate practice, Kornelius has particular expertise in the financial sector. He has published on capital markets law, and, during his PhD, was a visiting scholar at Harvard University (Cambridge, MA). His research focuses on financial market regulation and the circumstances under which breaches of regulatory obligations give rise to liability, considering EU and German regulatory frameworks as well as U.S. securities regulation.