Sun Chang is a partner in the IP Group. He is well-respected in the Korean legal community for his expertise in IP licensing and trade secret protection.

Since joining Lee & Ko in 2000 Mr. Chang has represented a number of multinational corporations including Samsung Electronics, Samsung Heavy Industries, Hanmi Pharmaceutical, Eli Lilly, Nautilus Hyosung in patent litigations. In particular, in TransOcean v. Samsung Heavy Industries, he successfully defended Samsung in a claim alleging infringement of TransOcean's patent for a drilling ship device for multi-tasking exploratory or developmental drilling, and invalidated TransOcean's patent.

Mr. Chang is highly regarded for his expertise in trade secret protection. He represented a number of high-tech companies including LG Electronics, Broadcom Corporation, KLA Tencor, POSCO, and Sodiff Advanced Materials in trade secret misappropriation cases, not only in civil lawsuits but in criminal prosecutions as well. He established and drafted guidelines for trade secret and information protection for LG jointly with law professors at the Seoul National University and structured trade secret protection system for POSCO.

Mr. Chang has also represented a number of clients (Lacoste, Asics, UEFA) in trademark disputes. Most notably, during the 2002 Korean-Japan Worldcup, he advised and represented FIFA in a nation-wide enforcement of FIFA's trademark rights that arose from ambush marketing, and represented Lacoste in the Korean part of a global battle against Crocodile and led to Lacoste's victory over the rights to crocodile logo by invalidating Crocodile International's crocodile logo. He also represented foreign trademark owners (Foot Locker, PRADA, Asics) in licensing negotiations and assisted in franchise transactions for international hotels (Hilton, Intercontinental), fast-food chains (McDonald's), coffee franchises (Cinnabon, Gloria Jean's), and franchise registration and regulatory matters before the Korean Fair Trade Commission.

Mr. Chang was also involved in several landmark cases, including the Korean Air v. Asiana Airlines, where he represented Korean Air in a claim for copyright infringement of Korean Air's Flight Operation Manual, and successfully acquired a ruling that the Flight Operation Manual, although mainly functional work, was subject to copyright protection.