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Madeline is a partner in the Corporate Department in Matheson specialising in mergers and acquisitions (public takeovers and private M&A), equity capital markets transactions, advisory matters and securities law.

Madeline has advised on many of the most significant Irish corporate transactions of recent years, involving international and Irish public and private companies across a wide range of industries and sectors.

In addition to her cross-border M&A experience, Madeline's practice involves advising on joint ventures, private equity, corporate restructurings, reorganisations and capital-raising transactions.

Madeline also counsels clients on corporate governance and advisory matters, including directors’ duties and responsibilities, and on the Irish Takeover Rules and securities regulation under the Market Abuse Regulation and the Irish Transparency and Prospectus regimes.

Madeline has contributed articles to international legal publications on mergers and acquisitions and corporate law in Ireland.

Experience Highlights

Recent transactions on which Madeline has advised include:

  • CGI Inc. on its recommended public takeover of Scisys Group plc.
  • Nexvet Biopharma plc on its recommended acquisition by Zoetis Inc.
  • Worldview Capital on its successful hostile takeover of Petroceltic International plc (ESM; AIM).
  • Weatherford International plc (NYSE) on a $1 billon registered direct offering of ordinary shares and warrants to acquire ordinary shares and a $1.1 billion underwritten public offering of senior exchangeable notes.
  • Abtran on the investment by Carlyle Cardinal Ireland.
  • Allergan’s $66 billion merger with Actavis (NYSE).
  • Perella Weinberg Partners LP on its role as financial adviser to US medical device maker Medtronic, Inc. on its $42.9 billion acquisition of Irish-based Covidien.
  • Actavis Inc (NYSE) on its $8.5 billion acquisition of Warner Chilcott plc (NASDAQ) and redomestication to Ireland.
  • The $2.6 billion acquisition of Auxilium Pharmaceuticals by Endo International.
  • William Grant & Sons Limited on the €300 million acquisition of the international spirits division of C&C Group Plc and the sale of Carolans, Frangelico and Irish Mist brands to Italian drinks producer Gruppo Campari for €129 million.
  • BC Partners on the Irish aspects of the €600 million acquisition of the Spotless Group.

Madeline is “collaborative, and technically excellent.”
IFLR 1000 2021

Madeline McDonnell is recommended.
European Legal 500 2020

Madeline McDonnell is named a next generation partner.
European Legal 500 2020

Madeline McDonnell is named a ‘Rising Star’
IFLR1000 2020

Madeline McDonnell is recommended.
European Legal 500 2019

Madeline McDonnell is "knowledgeable, hardworking and responsive. She works quickly and thoughtfully to find solutions to issues of first impression, always keeping the client’s objectives in mind".
Chambers Europe 2019

Madeline McDonnell has "an extremely commercial and professional style. She brought calm to sometimes very heated situations."
Chambers Europe 2019

Madeline McDonnell is named a Rising Star
IFLR1000 2019

Madeline McDonnell is recommended
European Legal 500 2018

Madeline McDonnell is named a Rising Star.
IFLR1000 2018

Madeline McDonnell is named a Rising Star.
IFLR1000 2017


Trinity College Dublin, LLB (First class)

Admitted as a Solicitor, Law Society of Ireland

Associate Member, American Bar Association (ABA)