Private company

Allen & Overy

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Multinational law firm

Allen & Overy LLP was a British multinational law firm headquartered in London, England. The firm had 590 partners and over 5,800 employees worldwide. In 2023 A&O reported an increase in revenue to GBP2.1 billion and was the second largest law firm headquartered in the UK by revenue.2 Wikipedia text CC BY-SA 4.0

Last updated Oct 21, 2026.

Overview

Jan 1, 1930Founded1

Allen & Overy LLP was a British multinational law firm headquartered in London, England. The firm had 590 partners and over 5,800 employees worldwide. In 2023 A&O reported an increase in revenue to GBP2.1 billion and was the second largest law firm headquartered in the UK by revenue. In 2024 it merged with Shearman & Sterling to form A&O Shearman.2

The story

Allen & Overy was founded in London on 1 January 1930 by George Allen and Thomas Overy, formerly partners at Roney & Co. The main purpose was to build a commercial practice. The firm's reputation was made as a result of George Allen's role as adviser to King Edward VIII during the abdication crisis of 1936. By the time World War II broke out in 1939, Allen & Overy had firmly established itself as a leading City law firm.

Allen & Overy was involved in many developments in the legal field. Such work has included advising on the first hostile takeover in the City of London and acting for S. G. Warburg & Co. The firm arranged the first Eurobond (issued by Italian motorway group Autostrada) in the 1960s. The Eurobond transaction significantly diversified Allen & Overy's practice from a purely commercial into commercial and financial firm. Through the 1970s the firm's finance and corporate practice grew in the UK and internationally.

In 1996, non-UK clients contributed more to Allen & Overy's revenue than UK clients. In 1998, non-UK clients contributed two-thirds of revenue.

In 1999, Allen & Overy hired a team of banking and finance lawyers in Paris from its then ally, Gide Loyrette Nouel.

In 2000, Allen & Overy merged with part of the Amsterdam, Brussels and Luxembourg offices of Loeff Claeys Verbeke.

In May 2004, the worldwide partnership of Allen & Overy converted to a limited liability partnership, Allen & Overy LLP, which works together with associated undertakings in some jurisdictions to form a worldwide legal practice. In July 2008 Allen & Overy broke the £1 billion turnover mark, and, for the first time, over half of its turnover was generated outside London.

In 2009, following the 2008 financial crisis, Allen & Overy completed a redundancy programme which saw 400 partners and staff lose their jobs globally. As well as cutting 47 partners, the firm cut around 200 fee-earners and 200 members of support staff, half of which were based in London. Allen & Overy de-equitised a further 35 partners. In the same year, Allen & Overy demerged its private client department, which became Maurice Turnor Gardner LLP.

In 2014, Allen & Overy became the first Magic Circle firm to establish an office in sub-Saharan Africa when it opened an office in Johannesburg, South Africa.

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A 2021 assessment singled out Allen & Overy among law firms as engaging in the most transactional work for fossil fuel companies.

On 21 May 2023 it was announced that Allen & Overy had agreed to terms in a merger with AMLaw100 member Shearman & Sterling, creating A&O Shearman over 4,000 attorneys across 48 offices with a combined revenue of $3.4bn. On 13 October 2023, the deal was approved by more than 99% of partners from both firms.

From Wikipedia’s article on Allen & Overy, shared under CC BY-SA 4.0.4

Products and brands

Steuart Walton – American heir, attorney, pilot, businessman and philanthropist.

From Wikipedia’s article on Allen & Overy, shared under CC BY-SA 4.0.4

Employees over time

  • 20168,0001

Revenue over time

As stated on Wikidata, in the currency reported.

Revenue

  • 20161.5B GBP1

Timeline

  1. Jan 1, 1930Founded Founded in London1

Sources

The numbers on this page point here. Each one links to the record it came from.

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