Paul Hastings Boosts Premier Antitrust Practice with Former FTC Official in Washington

Paul Hastings LLP announced today the addition of Lisa DeMarchi Sleigh, former FTC deputy assistant director in the Mergers I Division, to the firm’s market-leading Antitrust & Competition practice as a partner in Washington, D.C.

At the FTC, DeMarchi Sleigh analyzed proposed mergers and acquisitions and recommended enforcement actions focused primarily in the life sciences and healthcare sectors, including branded and generic pharmaceuticals, medical devices, consumer products and scientific and industrial products.

“Lisa is a powerhouse – her considerable experience at the FTC will be an invaluable resource for our corporate clients seeking sound, insider perspective and advice managing regulatory risks and challenges for their most important transactions,” said Paul Hastings Chair Frank Lopez. “Continuing to build our Antitrust & Competition practice remains a key priority for the growth of our broader private equity and public M&A platform, especially in the pharmaceutical and life sciences sectors, where increasing M&A volume and deal size portend a highly active market.”

DeMarchi Sleigh’s arrival, along with additional antitrust talent joining later this week, continues the strong growth of Paul Hastings’ global Antitrust & Competition practice, which has nearly tripled in size in the past four years with additions such as Salomé Cisnal De Ugarte from King & Spalding (Brussels); Sally Evans from Kirkland (London); former deputy director of the FTC’s Bureau of Competition Gail Levine from Mayer Brown, former chief of the Litigation I Section of the DOJ’s Antitrust Division (Washington, D.C.); Joshua Soven from Paul, Weiss (also in Washington, D.C.); and Stephen McIntyre (Los Angeles).

“I am delighted to join Paul Hastings and excited to work alongside such a dedicated and motivated team of antitrust lawyers supporting the firm’s premier corporate teams,” DeMarchi Sleigh said. “In transitioning to private practice after nearly two decades at the FTC, I can’t think of a more ideal setting for the next phase of my career than helping Paul Hastings’ clients navigate the complex antitrust review landscape for executing their corporate strategies.”

Paul Hastings is the No. 1 firm for U.S. deal value growth over the past two years, according to Bloomberg, with a 2025 total deal value 15 times the 2023 total — an increase to $272 billion from $18 billion. The firm’s average deal value climbed to $1.7 billion — nearly seven times its 2023 average of $254 million. In H1 2026, Paul Hastings ranked No. 11 among global firms for U.S. M&A deals by value, jumping 49 spots from 2023. The firm is also on pace to eclipse its 2025 results, with a total deal value of $198.5 billion for the first six months of 2026.

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