Mr Hans-Jakob Diem > Lenz & Staehelin > Zurich, Switzerland > Lawyer Profile

Lenz & Staehelin

Work Department

Corporate and Mergers & Acquisitions, Capital Markets, Corporate Governance, Banking and Finance


Hans-Jakob Diem is a corporate partner at Lenz & Staehelin. He heads the firm’s Corporate and M&A practice group and is the co-head of the Capital Markets practice group in Zurich. He has extensive experience in representing clients in a variety of corporate transactions, concentrating on mergers and acquisitions, capital market transactions, bank financings and corporate governance matters. Hans-Jakob Diem is regarded as a leading corporate practitioner in Switzerland and is regularly involved in high-profile transactions in the Swiss market, both domestic and cross-border. He also serves as principal outside counsel for a number of clients on stock exchange and securities trading law and corporate governance matters.

Besides his corporate practice, Hans-Jakob Diem lectures corporate and M&A law at the universities of Basel and Zurich and is a regular speaker at conferences, an author of various legal textbooks and a regular contributor in law journals. He is admitted as an expert to the SIX Swiss Exchange for Listing Purposes.


Admission to Basel Bar (1995), Joined Lenz & Staehelin (1998), Partner at Lenz & Staehelin (2007)


German, English, French


Zurich Bar Association (ZAV), Swiss Bar Association (SAV), International Bar Association (IBA), Swiss Private Equity & Corporate Finance Association (SECA), Swiss-American Chamber of Commerce, Swiss-Chinese Chamber of Commerce (SCCC), Swiss Institute of Directors, Swiss LSE Alumni Association


University of Basel (lic. iur., 1992), London School of Economics and Political Science (LL.M., 1998)

Lawyer Rankings

Switzerland > Commercial, corporate and M&A

(Leading individuals)

Hans-Jakob DiemLenz & Staehelin

Lenz & Staehelin has a highly reputed corporate and M&A practice with offices in both Zurich and Geneva. It assists clients from the financial services, healthcare and life sciences, TMT, manufacturing and real estate sectors with matters including public takeovers, private transactions and corporate governance. Practice head Hans-Jakob Diem has a strong, international practice. Rudolf Tschäni is an expert in public M&A, hostile takeover situations and related disputes. Tino Gaberthüel combines strength in commercial and corporate matters with capital markets expertise. Stephan Erni and Geneva-based Andreas RötheliJacques Iffland and David Ledermann are other prominent practitioners.

Switzerland > Leading firms: German-speaking Switzerland

Lenz & Staehelin has an excellent market reputation, with expertise in banking and finance, capital markets, corporate and M&A, and dispute resolution as well as in competition, IP, TMT, sports and tax matters. Key practitioners include Patrick Hünerwadel, Hans-Jakob DiemMarcel Tranchet, Harold Frey, Jürg SimonMarcel Meinhardt and Lukas Morscher.

Switzerland > Capital markets

Lenz & Staehelin‘s capital markets team impresses with its strong expertise in equity transactions, offerings of bonds, loan participation notes, mortgage-backed transactions, and convertibles, among others. It is experienced in acting for national as well as international clients and is often involved in cross-border work. Capital markets expert Jacques Iffland heads up the Geneva practice, where François Rayroux is a key contact on derivatives and structured products. Patrick Schleiffer is well versed in capital markets, stock exchange and securities law, among others. He leads the team in Zurich together with Hans-Jakob Diem, who is noted for his knowledge in capital market transactions.