郑天成先生是德勤上海国际税收与企业并购重组服务的合伙人，拥有超过15年的税务工作经验。他主要服务于在华投资的跨国集团、“走出去”的中国企业，以及在中国境外上市的集团。
郑先生专注于跨境交易的构架设计和商业模式规划、跨国公司全球税务规划、公司并购或重组税务影响分析及实施协助、以及美国会计准则下的所得税会计处理。郑先生是支柱二服务组核心成员，深度参与德勤全球网络中支柱二话题的研讨。
郑先生曾被借调至纽约办公室进行为期18个月的工作，是德勤美国“国际税务中心”的重要成员。
郑先生曾作为德勤中国税务技术中心的一员，参与内部的税务技术复核、法规讨论稿探讨等工作。
郑先生曾作为联合作者在《国际税收》杂志发表中国企业境外投资相关文章（包括“FIRPTA：投资美国易被忽视的房地产交易税收问题”及“中国企业海外并购的典型税务风险及应对”)。他还参与撰写了德勤领先理念出版物《私募基金：在华投资的架构设计》（仅英文版）及《中国企业境外并购项目的税务筹划》。
郑先生曾多次作为德勤在并购重组、国际税、“税基侵蚀利润转移”方面的专家为复旦大学MPAcc学员、上海财经大学税务硕士班的学生进行授课。他还定期作为中国税收主题的嘉宾为新加坡税务局设立的Tax Academy of Singapore组织开设的国际税收课程提供授课。
郑先生拥有复旦大学理学学士学位，是中国注册会计师和税务师。

Sheldon Zheng is a partner of International tax and M&A services of Deloitte Shanghai office. With over 15 years of experiences in the tax and accounting profession, Sheldon has focused on advising multinational companies investing in China, Chinese companies investing overseas, and China based companies that are listed overseas.
Sheldon has accumulated extensive experiences in the tax structuring for cross-border transactions, global tax planning for multinational corporations, tax due diligence and deal negotiation support for mergers and acquisitions, and accounting for income taxes under U.S. and international accounting standards. Sheldon is a core team member for Pillar Two services and has been actively involved in the global Pillar Two network of Deloitte.
Sheldon was seconded to Deloitte New York office for 18 months as part of International Core of Excellence (ICE) program.
Before joining ICE China desk, Sheldon was a key member of Deloitte China Tax National Technical Center, actively participating on internal technical review and discussion for Deloitte comments in draft tax circulars.
Sheldon wrote various articles and thought pieces including "Tax Risk Management for Outbound Investment by Chinese Companies" and “Taxation of Inbound Investors on US Real Property Transactions” (articles for "International Taxation in China" magazine), "Outbound M&A Tax Planning for Chinese Companies" (Deloitte thought piece), and "Private Equity Structures for Investing in China" (Deloitte thought piece).
He also lectured in multiple tax masters classes at the MPAcc class of Fudan University and the Shanghai University of Finance and Economics, as Deloitte China's subject matter specialist for M&A tax, international tax and BEPS. He also periodically lectured for the Advanced Tax Programme organized by Tax Academy of Singapore (a not-for-profit institution incorporated by Singapore tax authority).
Sheldon graduated from Fudan University. He is a member of CICPA and TA.