Praised for its ‘efficient and creative counsel’, the team at Simpson Thacher & Bartlett LLP guides clients through complex domestic and cross-border transactions in key industries including chemicals, financial services, pharma, telecoms and entertainment. The practice excels in domestic and international merger filings, DOJ and FTC investigations, including Second Request processes, and merger-related litigation. New York-based global co-chair Peter Guryan, described as ’extremely intelligent, responsive, respectful and practical‘, continues to be highly successful in merger mandates, notably representing L3Harris Technologies in its $4.7bn acquisition of Aerojet Rocketdyne Holdings. Sara Razi also co-chairs the antitrust team and is a key name for DOJ and FTC merger investigations as well as cross-border mandates, while Preston Miller has expertise in merger approvals and related investigations across a wide variety of industries. Karen Kazmerzak joined from Sidley Austin LLP in 2023, contributing significant experience of antitrust prosecution on the agency side. All lawyers mentioned are based in Washington DC, unless otherwise stated.

Legal 500 Editorial commentary

Testimonials

Collated independently by Legal 500 research team.

  • ‘STB is one of a few antitrust practices that are full service - they can handle any deal you throw at them and litigate it if necessary. Most firms say they can do this, but few can execute.'

  • 'One standout characteristic of the STB practice is their commercial view. They are great at balancing creative realities with the requirements of the antitrust laws. They provide efficient and creative counsel.’
  • ‘Max Fischer-Zernin is an uncommonly strong senior associate. I rely on him regularly.'

  • ‘The Simpson Thacher antitrust team is fantastic. They are commercial, practical, experts, friendly and extremely deep. They have the ability to staff from equally strong New York and Washington offices, and they can cover all areas from merger control, to conduct matters to criminal investigations. I also appreciate the strength they have in the HSR role, with multiple experts covering the difficult rules prescribed under Hart-Scott-Rodino.’

  • 'Peter Guryan - I cannot say enough good things about Peter. He is extremely intelligent, responsive, respectful and practical. He is a great team player, both among his colleagues and also with the other side of matters, thereby always looking for practical solutions rather than individual attribution.'
  • 'Preston Miller is up and coming. I have heard multiple partners from other law firms regularly describe Preston in glowing terms. This is because he is an extremely capable antitrust lawyer who always looks for concise and practical solutions. Preston is also very hard working.'
  • 'Richard Jamgochian is, hands down, one of the top HSR lawyers. Beyond HSR, he is able to oversee and coordinate large merger investigations. He is smart, precise and knows his stuff better than anyone.’
  • ‘The Antitrust team at Simpson Thacher is a pleasure to work with. Smart, efficient, practical and very diligent.’

Key clients

  • Blackstone
  • Buckeye Partners, L.P.
  • Change Healthcare
  • CSL Limited
  • Ferro Corporation
  • Garda World Security Corporation
  • HCA Healthcare, Inc.
  • KKR
  • The NPD Group
  • U.S. Bancorp

Work highlights

  • Represented Change Healthcare in its $13.8 Billion acquisition by UnitedHealth Group, including representing Change Healthcare in the highly publicized merger trial in which UnitedHealth and Change were victorious over the Department of Justice.
  • Represented L3Harris Technologies, Inc. in its $4.7 billion acquisition of Aerojet Rocketdyne Holdings, Inc.
  • Represented KKR in its $1.6 billion acquisition of Simon & Schuster from Paramount Global.

Lawyers

Leading partners
The strongest partners in their field, leading on market-leading deals and endorsed by peers and clients alike.
Next Generation Partners
Junior partners with significant recognition from clients and peers in the market and key roles on multiple matters.

Practice head

The lawyer(s) leading their teams.

Peter Guryan, Sara Razi, John Terzaken

Other key lawyers

Preston Miller, Richard Jamgochian, Karen Kazmerzak, Max Fischer-Zernin, Richard Jamgochian