Simpson Thacher

Simpson Thacher & Bartlett is a New York-headquartered law firm that's consistently ranked as one of the most prestigious firms in the world.

Founded in 1884 by Columbia University graduates John Woodruff Simpson, Thomas Thacher and William Milo Barnum, Simpson Thacher swiftly claimed a name for itself with landmark work - setting up companies for the likes of General Electric, the American Locomotive Company and the American Gas and Electric Company around the turn of the 20th century.

Today, with almost 1,500 lawyers across 13 offices globally, Simpson Thacher remains firmly at the top of the legal food chain. Known for its elite teams in M&A, private equity, capital markets and litigation, it has a track record of securing some of the most important mandates in corporate history. The firm has been involved in landmark IPOs for companies like Google, Facebook, Alibaba and Tesla - a handful of the largest tech listings in history.

Simpson Thacher’s international expansion began in the late 1970s, with its London office opening in 1978. Since then, the firm has continued to grow globally, opening offices in Tokyo (1990), Hong Kong (1993), Beijing (2007), São Paulo (2009) and Brussels (2021).

Simpson Thacher’s London office has become one of the firm’s most vital international hubs, and is now home to more than 250 lawyers, including more than 60 partners. In recent years, the office has expanded rapidly, cementing its place as a top player in high-profile M&A, private equity, funds, banking and capital markets transactions.

Growth in London has been fuelled by strategic lateral hires as well as internal promotions. The London office is located in Citypoint in Moorgate - which is also home to Simmons & Simmons and Willkie Farr. In 2025, as another sign of its growth intentions, Simpson Thacher announced plans to expand its presence in CityPoint by 13,000 sq ft.

That said, there is one thing missing from US firms' usual growth playbook in London - Simpson Thacher stands out for not offering a training contract. Instead, it hires graduates as paralegals to do trainee-level work, paying their SQE fees while they study, according to The Lawyer. Then, after qualification, these paralegals undergo a month-long trial to determine if they have the skills to be promoted to associate.

Outside of London, Simpson Thacher’s ambitions are similarly growth-oriented. The firm expanded its global footprint with the opening of a Boston office in September 2024. Then, in April 2025, it opened an office in Luxembourg with three funds partners hired from A&O Shearman and Clifford Chance. The office is about capitalising on Luxembourg’s role as a hub for private equity and venture capital funds.

The firm’s bet on global reach appears to be paying off. In 2024, as reported by The American Lawyer, Simpson Thacher posted impressive financial results, with revenue rising by 24% to $2.9 billion and profit per equity partner (PEP) shooting up by 19.1% to $7.6 million, marking one of the strongest years in its history.

Other things to know

AML breach fine: In March 2025, Simpson Thacher’s London office was fined £300,000 after the SRA approved a settlement over anti-money laundering (AML) control failures between 2017 and 2023. The SRA found the firm’s AML policies and controls were inadequate, though it accepted that no money laundering in fact took place.

Loss of star partners: Simpson Thacher’s London expansion has not come without its challenges. In 2023, top finance partners Ian Barratt and Sinead O’Shea left the firm for Kirkland & Ellis. The move caused much buzz in the legal world, with multiple sources claiming that Barratt was swayed away from Simpson Thacher with a compensation package worth up to $20 million a year.

A&O Shearman merger: Simpson Thacher played a key role in advising Allen & Overy on its landmark merger with Shearman & Sterling, with advice led by Jeannine McSweeney, an employee benefits and executive compensation partner at the firm.

What is Simpson Thacher known for?

Simpson Thacher is a full service corporate law firm. In the UK market, it is best known for its expertise in the following areas:

Private Equity: Considered to have one of the City's premier private equity practices for both corporate and finance advice, Simpson Thacher regularly advises on the biggest European deals for clients including KKR and EQT. It has a Band 2 ranking by Chambers for both buyouts and sponsor-side leveraged finance.

Investment Funds: Simpson Thacher is a go-to adviser for fund formation work, with a roster of the most prominent private equity and asset managers as clients. The practice has a Band 1 ranking by Chambers.

Restructuring and Insolvency: Simpson Thacher also has a highly regarded restructuring and insolvency practice. It has a Band 3 ranking by Chambers.

What's Chambers?

We use Chambers rankings to demonstrate a firm's strengths. Chambers is the most highly-regarded provider of law firm rankings in the legal industry. Law firms are ranked in bands from 1 (highest) to 6 (lowest) across a range of practice areas.

It's important to note that being ranked in any band at all is still considered a significant achievement.

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Who does Simpson Thacher compete with?

In the London market, Simpson Thacher competes with the leading private equity and leveraged finance practices, including the likes of Kirkland & Ellis, Latham & Watkins and the Magic Circle firms.

Simpson Thacher is among the 20 biggest law firms in the world by revenue. In 2024, its total revenue was $2.9 billion, according to ALM / Law.com.

In 2024, its profit per equity partner (PEP) was $7.6 million.

How much does a partner at Simpson Thacher make?

In 2024, Simpson Thacher's profit per equity partner (PEP) was $7.6 million, according to ALM / Law.com.

This is the total amount of profit available for distribution among equity partners, divided by the number of equity partners at the firm.This represents the average amount that equity partners are entitled to.

Some will receive significantly more, some less. It depends on the firm’s profit-sharing formula and each partner’s seniority.

How many trainees does Simpson Thacher take?

Simpson Thacher does not run a traditional training contract programme, instead preferring to train up its best paralegals to associate level - see above for more details.