Stephen Kastenberg > Ballard Spahr LLP > Philadelphia, United States > Lawyer Profile
Ballard Spahr LLP Offices

1735 MARKET STREET, 51ST FLOOR
PHILADELPHIA, PA 19103-7599
PENNSYLVANIA
United States
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Stephen Kastenberg

Work Department
Litigation
Position
Partner
Career
Stephen J. Kastenberg focuses on complex business litigation with an emphasis on antitrust and competition, securities, and corporate governance litigation. He has successfully defended public and private companies and universities in federal and state lawsuits, including class actions, throughout the United States. He also regularly represents clients as plaintiffs in business disputes, or assists them through internal investigations. Stephen is based in Philadelphia and is a member of the firm’s Elected and Expanded Boards.
In his nearly 30 years of litigation experience, Stephen has achieved a significant number of victories through trial, arbitration, summary judgment, advantageous settlement, and on appeal. His clients range from Fortune 100 multinational corporations to privately held companies and nonprofit organizations, and span such industry sectors as pharmaceuticals, chemicals, investments, media and technology, real estate, financial services, and higher education.
Admissions
New Jersey
Pennsylvania
Supreme Court of New Jersey
Supreme Court of Pennsylvania
U.S. District Court for the Eastern District of Pennsylvania
U.S. Court of Appeals for the Second Circuit
U.S. Court of Appeals for the Third Circuit
U.S. Court of Appeals for the Fourth Circuit
U.S. Court of Appeals for the Ninth Circuit
U.S. Court of Appeals for the Tenth Circuit
U.S. Court of Appeals for the Eleventh Circuit
Memberships
American Bar Association, Antitrust Section
New Jersey State Bar Association
Pennsylvania Bar Association
Philadelphia Bar Association
Ballard Spahr’s Pro Bono Committee
New Jersey Scholars Program, Member and past President
Lawyers’ Committee for Civil Rights, Director and Trustee
Police Corruption Task Force, past appointee by Philadelphia Mayor Edward Rendell
Education
Harvard Law School (J.D., cum laude, 1992)
Managing Editor, Harvard Journal on Legislation
Princeton University (A.B., cum laude, 1988)
Lawyer Rankings
United States > Antitrust > Civil litigation/class actions: defense
Ballard Spahr LLP remains active in numerous high-profile antitrust matters across the country, including MDLs, unlawful bundling, and conspiracy claims. The team is also experienced in criminal antitrust cases and is currently managing multiple DOJ and state investigations. The practice is led by Jason Leckerman, who has defended numerous companies in public and private class-action lawsuits. Stephen Kastenberg is a seasoned litigator with a record of success in trials, arbitrations, summary judgments, and appellate cases. Edward Rogers offers specialized expertise in real estate and construction matters, while New York-based James Mitchell focuses on securities. All attorneys are based in Pennsylvania unless otherwise noted.
United States > Philadelphia Elite > Commercial disputes
(Commercial disputes)Stephen Kastenberg of Ballard Spahr LLP is a go-to litigator for Fortune 500s and major institutions navigating high-stakes, high-profile disputes. A trusted advisor to Comcast, GlaxoSmithKline, Nasdaq, and Princeton, he leads on complex antitrust, patent, and governance matters across jurisdictions. Recently, he spearheaded Nasdaq’s defense in a closely watched SEC-related funding battle. Known for strategic insight and long-term client partnerships, Kastenberg is a standout practitioner in sophisticated commercial litigation.
Lawyer Rankings
- Commercial disputes United States > Philadelphia Elite
- Commercial disputes United States > Philadelphia Elite > Commercial disputes
- Civil litigation/class actions: defense United States > Antitrust
Top Tier Firm Rankings
- Philadelphia Elite > Commercial disputes
- Philadelphia Elite > Commercial disputes
- Philadelphia Elite > Corporate and M&A
- Philadelphia Elite > Corporate and M&A
- Finance > Financial services regulation
- Philadelphia Elite > Intellectual Property
- Philadelphia Elite > Corporate and M&A
- Finance > Project finance
Firm Rankings
- Philadelphia Elite > Commercial disputes
- M&A/corporate and commercial > M&A: middle-market (sub-$500m)
- Real estate > Real estate investment trusts (REITs)
- Finance > Restructuring (including bankruptcy): municipal
- Philadelphia Elite > Corporate and M&A
- Finance > Fintech
- Labor and employment > Labor-management relations
- Real estate > Land use/zoning
- Media, technology and telecoms > Media and entertainment: litigation
- Dispute resolution > Product liability, mass tort and class action - defense: automotive/transport
- Real estate > Real estate
- Labor and employment > Employee benefits, executive compensation and retirement plans: design
- Dispute resolution > Financial services litigation
- Real estate > Real estate finance
- Energy > Renewable/alternative power
- Antitrust > Civil litigation/class actions: defense
- Dispute resolution > Securities litigation: defense
- Dispute resolution > Corporate investigations and white-collar criminal defense