Cozen O’Connor

Cozen O’Connor

Name	Cozen O’Connor
Headquarters	One Liberty Place, 1650 Market Street, Suite 2800, Philadelphia, Pennsylvania, United States
Num Offices	33
Num Attorneys	925+
Practice Areas	Litigation; Corporate; Regulatory; Intellectual Property; Real Estate; Labor & Employment; Insurance; Government Relations
Key People	Michael J. Heller (Executive Chairman & CEO); Vincent R. McGuinness (President & Managing Partner)
Date Founded	1970
Founder	Stephen A. Cozen
Company Type	Professional corporation

Cozen O’Connor is an international law firm headquartered in Philadelphia, Pennsylvania. Founded in 1970 by Stephen A. Cozen, the firm has grown into a full-service practice with more than 925 attorneys across 33 offices in the United States, Canada, and the United Kingdom. Cozen O’Connor is regularly ranked among the largest U.S. law firms and maintains nationally recognized practices in litigation, corporate and regulatory law, and government relations. The firm also operates several affiliated businesses—including a bipartisan government affairs shop (Cozen O’Connor Public Strategies), a risk and security consultancy (COSECURE), and a subrogation services company (National Subrogation Services)—which broaden its service offerings for clients.

History

Cozen O’Connor traces its origins to 1970, when litigator Stephen A. Cozen established the firm in Philadelphia. From the outset, the practice focused on complex insurance, commercial, and subrogation matters—areas that laid the groundwork for nationwide expansion throughout the 1980s and 1990s. By the early 2000s, the firm had diversified into corporate, real estate, labor and employment, intellectual property, and regulatory work and opened offices in major U.S. legal markets such as New York, Washington, D.C., and Los Angeles.

In the 2010s and 2020s, Cozen O’Connor added offices across North America and in London, while broadening industry coverage. In February 2023, the firm announced an intellectual-property-focused office in Boulder, Colorado, anchored by an eight-person team from Lathrop GPM; press coverage noted the move as part of a broader wave of Am Law firms expanding into Colorado’s “Mountain West” market.

The firm’s leadership includes Executive Chairman and CEO Michael J. Heller and President and Managing Partner Vincent R. McGuinness, who oversee the firm’s strategic growth, operations, and practice management.

Offices

Cozen O’Connor maintains 33 offices across North America and Europe, including major hubs in Philadelphia, New York, Washington, D.C., Chicago, Boston, Los Angeles, San Diego, San Francisco, Santa Monica, Seattle, Atlanta, Minneapolis, Dallas, Houston, Miami, West Palm Beach, Denver, Boulder, Charlotte, Richmond, Las Vegas, Salt Lake City, and others. Internationally, the firm has offices in Montreal, Toronto, Vancouver, and London. The firm’s headquarters are located at One Liberty Place in downtown Philadelphia.

Practice areas

Cozen O’Connor describes itself as a full-service firm with capabilities spanning litigation, corporate transactions, and regulatory counseling. Core and notable areas include:

Litigation and Investigations – commercial litigation, class actions, white-collar defense and investigations, antitrust, product liability, construction, and appellate advocacy.

Corporate – mergers and acquisitions, capital markets, private equity, corporate governance, finance, and emerging business services, including a dedicated Family Office practice supported by HomeBase, the Family Office @ Cozen O’Connor.

Regulatory – aviation, energy, environmental, privacy and cybersecurity, healthcare, cannabis, and government relations, among others.

Insurance and Subrogation – long a hallmark of the firm, Cozen O’Connor and its affiliate National Subrogation Services handle high-volume and complex subrogation and recovery matters nationwide and internationally.

Intellectual Property – patents, trademarks, copyrights, trade secrets, and IP litigation, with the Boulder office (opened 2023) strengthening the firm’s presence in technology hubs.

Government relations (Cozen O’Connor Public Strategies)

Cozen O’Connor Public Strategies (CPS) is the firm’s bipartisan government-relations and strategic-communications affiliate. CPS advises clients at the federal, state, and local levels and maintains teams in Washington, D.C., New York, Illinois (Chicago and Springfield), Pennsylvania, and other jurisdictions. Federal filings compiled by OpenSecrets show that Cozen O’Connor’s federal lobbying clients and billings have grown in recent years, with 73 clients and approximately US$5.1 million in federal lobbying in 2025 (year-to-date at time of reporting). CPS is led by CEO Howard Schweitzer, who also serves on Cozen O’Connor’s board of directors.

Notable matters

Michael E. Mann defamation litigation (D.C. Superior Court). In February 2024, after a multi-week trial, a District of Columbia jury found two writers liable for defamation of climate scientist Michael Mann and awarded punitive damages of US$1,000,000 (against Mark Steyn) and US$1,000 (against Rand Simberg), with nominal compensatory damages of US$1 each. In a March 3, 2025 omnibus order on post-trial motions, the court granted remittitur and reduced the punitive damages against Steyn to US$5,000, while otherwise denying requests for judgment as a matter of law and a new trial. Cozen O’Connor served as part of Dr. Mann’s counsel team.

Freedom-of-information litigation related to academic research. The Virginia Supreme Court held in 2014 that the University of Virginia was not required to release certain emails of former professor Michael Mann in response to a records request, clarifying FOIA exemptions for proprietary academic records. Cozen O’Connor attorneys were involved in related proceedings surrounding access and privacy in research records.

Political law practice formation. In November 2023, Cozen O’Connor launched a political law and compliance practice led by election law attorney Jerry Goldfeder, reflecting the firm’s expansion in campaign-finance, election, and ethics counseling.

Rankings and recognition

Cozen O’Connor is consistently recognized by major legal directories and trade publications. Chambers USA (2025) lists the firm across dozens of departments and more than 100 ranked lawyers nationwide. Firm communications have noted repeated recognition by The Legal 500, Best Lawyers, and inclusion in workplace rankings such as Newsweek’s Global Most Loved Workplaces (2025).

Affiliated and ancillary businesses

Cozen O’Connor operates or is affiliated with several businesses that complement the law practice:

Cozen O’Connor Public Strategies (CPS) – a bipartisan government-relations and communications firm with federal, state, and local practices in multiple jurisdictions.

National Subrogation Services (NSS) – a wholly owned affiliate providing nationwide subrogation and recovery services for insurers and self-insureds.

COSECURE – a risk management and cybersecurity consultancy, staffed by former law-enforcement and security professionals, offering assessments, incident response, and advisory services.

HomeBase, the Family Office @ Cozen O’Connor – a non-investment advisory multifamily office platform supporting high-net-worth families.

Pro bono and community engagement

Cozen O’Connor maintains a longstanding pro bono program, reporting tens of thousands of attorney hours devoted to representing indigent individuals and nonprofits. The firm is a signatory to the Pro Bono Institute’s Law Firm Pro Bono Challenge and has publicized an internal goal of dedicating 3% of billable hours to pro bono matters each year. In 2023, for example, pro bono counsel helped secure the early release of an incarcerated domestic-violence survivor through New York’s DVSJA resentencing process, a result highlighted by advocacy organization Sanctuary for Families.

Through the Cozen O’Connor Charitable Foundation—incorporated in the early 2000s—the firm provides philanthropic support to schools, medical centers, cultural institutions, and other nonprofits. Public filings show the foundation distributed roughly US$2.29 million in grants in 2023.

Diversity, equity, and inclusion

Cozen O’Connor reports participation in the legal industry’s Mansfield Certification program, which encourages transparent and inclusive leadership pipelines. Firm leaders have publicly cited increased diversity in partner classes since adopting Mansfield practices. The firm also operates scholarships and fellowships to support pipeline development into the profession and has publicized internal programming aligned with cultural and heritage months.

Leadership and governance

As of 2025, Cozen O’Connor is led by Executive Chairman and Chief Executive Officer Michael J. Heller and President and Managing Partner Vincent R. McGuinness. The firm’s governance includes a board of directors and department leadership spanning business law, litigation, and regulatory practices. CPS is led by CEO Howard Schweitzer.

Reputation and rankings in the legal market

Chambers and Partners and other directories regularly rank Cozen O’Connor in multiple practice areas and jurisdictions, including aviation, construction, immigration, insurance, maritime, and M&A, among others. Chambers Associate describes the firm as a top-100 U.S. law firm with more than 925 attorneys across 32+ cities and “nationally recognized practices in litigation, business law, and government relations.”

Recent expansion and initiatives

In addition to the Boulder launch, Cozen O’Connor has publicized growth of its IP, labor and employment, and regulatory teams, as well as recognitions in directories and workplace rankings through 2024–2025. The firm’s Privacy and Cybersecurity lawyers publish guidance and speak on incident response and compliance topics, often in coordination with COSECURE’s forensic and security work.

Address

The firm’s principal office is located at One Liberty Place, 1650 Market Street, Suite 2800, Philadelphia, PA 19103, United States.

See also

List of largest law firms by revenue

List of largest United States-based law firms by headcount

Lobbying in the United States

External links

https://www.cozen.com/

Cozen O’Connor Public Strategies

National Subrogation Services

COSECURE