PRESS RELEASE
18 August 2025

A&O Shearman Advises Mallinckrodt Plc On International Aspects Of Its Merger With Endo, Inc.

AO
A&O Shearman

Contributor

A&O Shearman was formed in 2024 via the merger of two historic firms, Allen & Overy and Shearman & Sterling. With nearly 4,000 lawyers globally, we are equally fluent in English law, U.S. law and the laws of the world’s most dynamic markets. This combination creates a new kind of law firm, one built to achieve unparalleled outcomes for our clients on their most complex, multijurisdictional matters – everywhere in the world. A firm that advises at the forefront of the forces changing the current of global business and that is unrivalled in its global strength. Our clients benefit from the collective experience of teams who work with many of the world’s most influential companies and institutions, and have a history of precedent-setting innovations. Together our lawyers advise more than a third of NYSE-listed businesses, a fifth of the NASDAQ and a notable proportion of the London Stock Exchange, the Euronext, Euronext Paris and the Tokyo and Hong Kong Stock Exchanges.
A&O Shearman has advised longstanding client Mallinckrodt plc, a global pharmaceutical company, on certain international legal aspects of its landmark merger with Endo, Inc., a leading provider of innovative pharmaceutical products.
United States

A&OShearman has advised longstanding client Mallinckrodt plc, a global pharmaceutical company, on certain international legal aspects of its landmark merger with Endo, Inc., a leading provider of innovative pharmaceutical products.

This transformative transaction brings together two major players in the specialty and generic pharmaceuticals sector, creating a more diversified and resilient business with a combined focus on specialty pharmaceuticals, specialty generics and hospital products.

The merger, signed on March 13, 2025, and completed on July 31, 2025, involved complex cross-border legal, regulatory and financial arrangements, reflecting the international footprint of both companies. The combined company will have a robust operating presence, primarily in the United States, supported by capabilities in Europe, India, Australia and Japan, with 17 manufacturing facilities, 30 distribution centers and approximately 5,700 employees at closing.

The A&OShearman team was led out of London by corporate partner Gillian Holgate and associates Khin Hsu Myat, Kemilia Ogunmuyiwa and Noel Low. Specialist advice was provided by the A&OShearman Antitrust/FDI, Employment and Tax teams. A&OShearman offices in Luxembourg, Netherlands, and Germany advised on corporate and financing matters.

"We hugely value our longstanding relationship with Mallinckrodt and look forward to supporting them as they embark on this next phase of growth." - Gillian Holgate - Partner

Gillian Holgate, partner at A&OShearman, commented: "We are delighted to have assisted Mallinckrodt on this landmark merger with Endo, which marks a significant milestone for both companies and the wider pharmaceuticals sector. This transaction, coming directly on the heels of the successful carve-out sale of the Therakos business last year, further demonstrates Mallinckrodt's strategic vision and our ability to support them on their most complex and transformative matters. We hugely value our longstanding relationship with Mallinckrodt and look forward to supporting them as they embark on this next phase of growth."

Contributor

A&O Shearman was formed in 2024 via the merger of two historic firms, Allen & Overy and Shearman & Sterling. With nearly 4,000 lawyers globally, we are equally fluent in English law, U.S. law and the laws of the world’s most dynamic markets. This combination creates a new kind of law firm, one built to achieve unparalleled outcomes for our clients on their most complex, multijurisdictional matters – everywhere in the world. A firm that advises at the forefront of the forces changing the current of global business and that is unrivalled in its global strength. Our clients benefit from the collective experience of teams who work with many of the world’s most influential companies and institutions, and have a history of precedent-setting innovations. Together our lawyers advise more than a third of NYSE-listed businesses, a fifth of the NASDAQ and a notable proportion of the London Stock Exchange, the Euronext, Euronext Paris and the Tokyo and Hong Kong Stock Exchanges.

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