A&O Shearman: the mega law firm merger goes live today. Here’s what you need to know

The most highly anticipated merger in the legal sector formally completes today, operating under a new name A&O Shearman.

Magic circle firm Allen & Overy (A&O) and US firm Shearman & Sterling shocked the legal sector last May when they announced the proposed merger.

With the merger completing today, A&O Shearman becomes one of the biggest law firms in the world, with $3.5bn in revenue and nearly 4,000 lawyers globally.

Why?

The aim behind the merger was to give both firms access to more markets. The combined firm now has 48 offices in 29 countries.

Legacy firm A&O was part of the well-known magic circle firms – one of the five most prestigious London-headquartered law firms.

A&O had a strong brand in the United Kingdom, but despite its best efforts in expanding into the United States, it lacked a reputation in that legal market. Shearman & Sterling, however, was a heavyweight US law firm, headquartered in New York.

A&O gains a $1bn US business with brand recognition, while Shearman & Sterling gain a foothold in the UK and rest of the world.

Both firms held elections on the merger proposal, and it was revealed in October that more than 99 per cent of the votes cast at each firm were in favour of the merger.

The new ‘megafirm’

For much of the last 11 months, the firms have been integrating their operations.

In March, it was revealed that Abu Dhabi-based partner Khalid Garousha had been elected as senior partner and Paris-based Hervé Ekué was elected as managing partner of A&O Shearman.

Garousha was A&O’s interim managing partner after being appointed in July, but as of May, he will be in the senior partner role. While Ekué will take on the managing partner role, having been at A&O for over 23 years.

It was announced on Tuesday, that A&O London-based Denise Gibson was appointed as managing partner for the UK. New York’s A&O partner Dave Lewis and Shearman’s New York partner Doreen Lilienfeld were appointed co-managing partners of the US.

In terms of its London HQ, the firm will be in One Bishops Square in London, A&O’s current office, before relocating to 2 Broadgate in early 2027. While in New York, it will operate out of Shearman’s offices at 599 Lexington Avenue.

According to data published in March by Pirical, since the merger was announced, Shearman lost nine per cent of its partners, while A&O lost three per cent. On Shearman, most of its loss was outside the US, with the highest total number of exits coming from Paris and London.

Pirical noted that compared to other firms going through or having completed mergers, Shearman lost more partners than the average figure of four per cent.

The firm revealed its first batch of partner promos earlier this month. Together, 40 lawyers were elected to the partnership (A&O: 32 and Shearman: 8). They will join the A&O Shearman partnership upon the merger closing on 1 May.