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Sullivan & Cromwell LLP

125 BROAD STREET, NEW YORK 10004-2498, USA
Work +1 212 558 4000
Fax +1 212 558 3588

Yvonne S. Quinn

Work +1 212 558 3736
Sullivan & Cromwell LLP

Work Department





Partner since 1984. Co-head, Antitrust Group. Antitrust litigation, merger analysis/review and counseling work as well as general commercial litigation. Clients: consumer products companies, leading commercial banks, equity funds, investment banks, insurance companies, cable television operators, television programming suppliers, newspapers, publishers, sports franchise owners, advertising sales, healthcare, pharmaceutical and chemical companies and accounting standards boards, among many others.


ABA (Antitrust Section); NYSBA (Executive Committee, Antitrust Section); New York City Bar Association (former Chair, Antitrust and Trade Regulation Committee); FBC.


University of Michigan (MA, Economics, 1977); University of Michigan Law School (JD, 1976); University of Illinois (BA, 1973).

United States: Antitrust

Civil litigation/class actions

Within: Civil litigation/class actions

Steven Holley and Yvonne Quinn (both in New York) and Daryl Libow jointly head the practice at Sullivan & Cromwell LLP, which handles follow-on actions arising from criminal antitrust investigations, standalone class actions (where no government investigation is involved) and private inter-competitor litigation. The firm is particularly successful in handling cutting-edge mandates for financial institutions. In a recent highlight, Libow and Amanda Flug Davidoff defended JPMorgan Chase & Co against three silver futures rigging lawsuits brought by silver futures traders. New York-based Richard Pepperman successfully represented Goldman Sachs as a defendant in a class action involving an alleged zinc price-fixing conspiracy. Recently promoted partner Joseph Matelis as well Robert Sacks and Adam Paris in Los Angeles are other key individuals in the team. Unless stated otherwise, named lawyers are based in Washington DC.

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Merger control

Within: Merger control

Sullivan & Cromwell LLP’s Steven Holley, Daryl Libow and Yvonne Quinn jointly head the firm’s antitrust team, which handles every stage of the merger process for clients from a multitude of sectors. Holley is assisting Bayer with the merger clearance aspects of its $66bn acquisition of Monsanto. In another matter, recently promoted partner Joseph Matelis, based in New York, acted as antitrust counsel to Columbia Pipeline Group in its $13bn acquisition by TransCanada. Los Angeles-based Adam Paris is experienced in handling DOJ and FTC merger investigations. Holley and Quinn are based in New York, while Libow is based in Washington DC.

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