O'Neill, William P.

William P. O'Neill

Retired Partner

William O'Neill retired from the partnership in December 2018. He was a partner in the Washington, D.C. office, and has more than 34 years of experience representing public companies and their boards of directors in strategic and transformative transactions. From 2001-2007 he served as Chair of Latham & Watkins’ Corporate Practice in Washington, D.C., growing the department from fewer than 30 to more than 90 partners and associates.

Mr. O’Neill’s wealth of experience includes:

  • Mergers
  • Exchange and tender offers 
  • Asset purchases and dispositions 
  • Stock acquisitions 
  • Leveraged buyouts 
  • Divestitures and spin-offs for publicly traded corporations, private equity funds, and their portfolio companies 
  • Corporate finance aspects of acquisitions 
  • LBOs and leveraged recapitalizations, including representation of newly formed issuers in public offerings 
  • Exchange offers and private placements of equity 
  • Debt and convertible securities

He also has substantial experience in advising boards and special committees on disclosure issues, corporate governance matters, and business judgment rule principles in the context of material transactions.

Mr. O’Neill frequently advised companies and audit committees on `34 Act reporting requirements, financial restatements, general securities law, the Sarbanes-Oxley Act, and NYSE and NASDAQ rule compliance.

Thought Leadership

  • Frequent speaker at PLI and other CLE programs, the KPMG semi-annual Audit Committee Roundtable, and before the National Investor Relations Institute 
  • Often invited to speak before in-house corporate department seminars and retreats on developments in mergers and acquisitions and securities law and regulation 
  • Has published articles and outlines on a variety of business and securities law topics; from 1984-1989 served as the Editorial Chair of the ABA Antitrust Law Journal

From 2003-2006 Mr. O'Neill was a member of the Committee of Visitors for the University of Michigan Law School. He served on the Board of Trustees for St. Patrick's Episcopal Day School in Washington, D.C. from 2004-2011.


  • JD, University of Michigan Law School, 1976
  • BA, The University of Kansas, 1973