DLA Piper has appointed Mark Whiteside as a partner in its United Kingdom Transactional Tax practice, effective November 9, 2026. Whiteside joins from CMS, where he served as a partner in Manchester and led the firm’s regional transactional tax practice.
The appointment strengthens DLA Piper’s tax advisory capabilities, particularly in connection with mergers and acquisitions, corporate restructurings, real estate transactions, and other complex business activities.
Whiteside brings experience advising clients on UK and cross-border transactions, including the tax considerations associated with business acquisitions, reorganizations, and investment structures.
His practice spans corporate taxation, real estate taxation, value-added tax, venture capital arrangements, and employee incentive structures.
At DLA Piper, Whiteside will support clients seeking coordinated legal and tax advice across the transaction lifecycle, from initial structuring and due diligence through completion and post-transaction integration.
Tax planning is an important component of corporate transactions, affecting acquisition structures, financing arrangements, shareholder returns, management incentives, and the treatment of assets and liabilities.
For international transactions, companies must also navigate the interaction of tax rules across different jurisdictions, creating additional requirements for coordinated advisory services.
Whiteside’s experience in both domestic and cross-border matters will complement DLA Piper’s existing corporate and transactional practices.
His arrival follows the appointment of Gareth Amdor, who joined DLA Piper from Reed Smith earlier in 2026 to lead the firm’s Transactional Tax team.
Together, the appointments expand the senior resources available to support clients on acquisitions, investments, restructurings, and other business transactions.
DLA Piper’s broader strategy includes strengthening the integration of its tax advisory services with its mergers and acquisitions capabilities.
In addition to advising on transaction structures, the team’s responsibilities include supporting management equity arrangements and helping clients address tax matters arising after acquisitions and corporate reorganizations.
These capabilities are relevant to private equity sponsors, corporations, and investors that require specialized tax advice alongside other legal services.
The addition of Whiteside expands the firm’s ability to advise on the tax implications of complex investments and strategic business decisions across the UK market.
The appointment also strengthens its capacity to support clients operating internationally, where regulatory and tax considerations can affect transaction execution and long-term investment outcomes.
KEY QUOTE:
“We are delighted to welcome Mark into the UK Transactional Tax team. His arrival builds on the appointment of Gareth Amdor who joined us from Reed Smith at the start of the year to head up the Transactional Tax team. These appointments significantly enhance the tax support required to structure M&A transactions effectively and to deliver seamlessly for our clients.”
Jason Collins, UK Head Of Tax At DLA Piper
