Mark Side



Mark has been with Tanner De Witt since 2000 and is highly regarded in Hong Kong as a commercial and family litigator. Mark’s practice today focuses on contentious regulatory matters along with family and private wealth matters and disputes within professional partnerships, particularly within the legal industry. Mark has long-standing relationships with his clients and with professional intermediaries such as mediators, barristers, arbitrators and private investigators. Chambers Asia notes that Mark is “strategically very strong, mindful of our concerns and [he] always explains the contributing factors to his advice”.

Mark advises on a wide range of civil and commercial disputes. In recent years Mark has advised on a number of complex and high-value shareholder disputes. A large part of Mark’s practice continues to involve representing senior partners at domestic and international law firms in Hong Kong in their partnership disputes. Mark’s clients include high net worth individuals, financial companies, public companies, private individuals and accountants.

Mark was the driving force behind the creation of Tanner De Witt’s Family practice and continues to play an instrumental role within it alongside Joanne Brown. He is well respected for providing strategic advice and support to families going through challenging times both emotionally and financially. His role involves advising high net worth families and individuals on the structuring of estates and asset preservation in a divorce context.

A CEDR-accredited mediator, Mark understands the long-term consequences on individuals involved in high conflict commercial and family disputes and he encourages the use of less aggressive means to reach amicable agreements. This is particularly effective in achieving pre-action settlement in family and divorce cases. Whether acting in his capacity as a lawyer or as a mediator, clients choose Mark for his open and fair approach to sensitive matters and he builds excellent relationships with clients.

Mark is included in the Chambers High Net Worth Guide 2021 for his work advising individuals on contentious private wealth matters. This includes acting for a range of clients including trustees, executors and administrators, banks and beneficiaries and private individuals in trust and probate disputes. Mark has particular experience advising individuals and families on the Mental Health Ordinance (MHO) and advising on matters under the Inheritance (Provision for Family and Dependants) Act 1975).

Mark’s professional practice also includes advising clients engaged in complex investigations on white collar crime and regulatory issues. He is experienced in appearing before the regulators, tribunals and administrative bodies that control the affairs of regulated professions and industries in Hong Kong. Most recently this has included advising on the recently introduced National Security Law within the Hong Kong Police Force.



Key cases

  • Acting as mediator in a dispute concerning the alleged unlawful dilution of a public shareholding by a European company.
  • Defending a party in its proceedings as defendant against an international bank, who is alleged to have misappropriated the assets of a charitable estate.
  • Supervising execution of Anton Piller orders obtained by other parties
  • Representing key individuals in Commissions of Enquiry from time to time
  • Acting for a former husband to pursue proceedings to vary downwards court ordered maintenance payments
  • Conducting landmark employment action in Hong Kong acting for leaving partner of a well-known Hong Kong firm
  • Acting for a finance professional in a long-term wardship case that involves allegations of sexual abuse and violence towards the child. The case also involves complicated access and financial disputes
  • Acting for a husband in a case involving divorce, a postnuptial agreement, ongoing issues regarding execution and administration of the post-nuptial agreement
  • Acting for the husband in a long marriage with complex matrimonial asset valuation issues specifically international commercial and hedge fund structures. Assets are held in Hong Kong, UK and the US



Chambers and Partners 2023 states, “Mark has long-standing relationships with his clients and with professional intermediaries such as mediators, barristers, arbitrators and private investigators. Chambers Asia notes that Mark is ‘strategically very strong, mindful of our concerns and [he] always explains the contributing factors to his advice.'”

Listed as a leading lawyer in Chambers Greater China 2022: Mark is a “strong, pragmatic commercial dispute resolution lawyer.”

Legal 500 Asia Pacific 2022 notes: ‘Mark Side is a tough adversary for commercial disputes.’

Listed as a leading lawyer for Private Wealth Disputes in Chambers High Net Worth Guide 2021: Mark Side leads the firm’s dispute resolution team and frequently acts for high-net-worth clients in family wealth and trust disputes. He is also an accredited mediator.

Listed as a leading lawyer in Chambers Asia and Chambers Global 2021 Guides: Mark Side is head of the firm’s dispute resolution team. He is known for handling employment disputes, as well as contentious regulatory matters and white-collar crime investigations.

Legal 500 Asia Pacific 2021 notes: ‘Sound advice and a very collaborative team to work with. Great bunch of people and well respected in the market’.

Asian Legal Business Hong Kong Law Awards 2020 – Family and Matrimonial Law Firm of the Year.

Chambers Asia Pacific 2020 notes: Mark Side’s “excellent tactical awareness” and report that “his experience and understanding of the bigger picture is valuable in developing a sound litigation strategy.” His broad scope of litigation experience spans contentious regulatory matters, white-collar crime investigations and professional duty disputes.

Legal 500 Asia Pacific 2020 notes: Sources praise Mark Side stands out for his ‘fantastic knowledge’; he leads the team with Jeff Lane and Pamela Mak.

Asia Pacific Legal 500 2019 notes: Mark Side leads the team at Tanner De Witt, which recently assisted Grant MacEwan University with tracing and recovery of CA$11.8m misappropriated through cyber fraud, with the team facilitating the recovery of approximately CA$4m in Hong Kong through obtaining a series of emergency injunctions and disclosure orders.

Chambers Asia Pacific 2019 notes: Mark Side has a wide-ranging litigation practice that includes expertise in restrictive covenant and professional duty disputes, matrimonial asset tracing and white-collar crime.

Chambers Asia Pacific 2018 notes: Mark Side focuses his practice on contentious regulatory matters, with additional experience in matrimonial asset tracing and professional duty disputes. Sources regard him as a “well-known Hong Kong practitioner” and a “good litigator.”

Chambers Asia Pacific 2017 notes: Mark is a committed mediator and litigator with solid experience in handling major disputes for clients such as public companies, shareholders and accountants. Market sources comment that “he is a good all-rounder” who “has been around the market for a long time.”

Asia Pacific Legal 500 2017 notes: The [dispute resolution and litigation] practice at Tanner De Witt is led by Mark Side, who is acting for a high-net-worth individual in a professional negligence claim against an international bank.

Asialaw Leading Lawyers 2017 notes: “Mark Side is very personable with excellent knowledge of the jurisdiction,” says a client.

2016 notes: “A client appreciates that Mark Side is ‘strategically very strong, mindful of our concerns and always explains the contributing factors to his advice’. He acts for public companies, shareholders and accountants, among others. He is also known for his work as a mediator.”

Asia Pacific Legal 500 2016 notes: “Tanner De Witt attracts very strong peer and client feedback. Department head Mark Side is ‘very good on licensing and matrimonial issues.’”



Professional memberships

Other memberships

  • Foreign Correspondents’ Club, Hong Kong
  • Royal Asiatic Society
  • Royal Geographical Society