Stephen M. Medlock

Partner

Antitrust

“I take pride in efficiently resolving my clients’ highest stakes and most complex antitrust matters. I learn my clients’ business inside and out so that I can find the solutions that others don’t see.”

Stephen Medlock

Overview

Steve Medlock is an experienced antitrust litigator who brings dedication, intensity, and commercial common sense to his representations of Fortune 500 clients, whether navigating through complex multidistrict class actions or successfully defending clients in grand jury investigations. Clients place their trust in Steve to develop unique and complex antitrust arguments for both defendants and plaintiffs. Steve’s unique mix of plaintiff and defense-side experience allows him to see the issues that exclusive defense-sided practitioners miss in a full range of antitrust matters, including corporate counseling, internal investigations, civil non-merger and criminal cartel investigations, and litigation. In these areas, Steve is known for providing practical advice that business executives can digest. Steve has secured victories for clients in major antitrust class actions and B2B antitrust cases alleging monopolization and attempted monopolization at critical stages, including winning dismissal prior to discovery and prevailing at summary judgment. His depositions and briefs have been quoted in the The New York Times, The Washington Post, The Atlantic, and several other major media outlets.

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Experience

  • Representing Optimal Blue and Constellation Software in connection with antitrust class action alleging algorithmic price-fixing and improper sharing of competitively sensitive information

  • Representing Rouse Services and Rouse Analytics in connection with antitrust class actions alleging algorithmic price-fixing and improper sharing of competitively sensitive information

  • Representing food company in connection with government antitrust investigation

  • Representing professional sports team in connection with government investigation and litigation

  • Representing Delta Dental member companies in connection with a series of consolidated class actions alleging that Delta Dental companies underpaid dentists

  • Representing national property management companies in connection with a series of consolidated class actions alleging the existence of a conspiracy to increase or stabilize the price of apartments using a common algorithm

  • Representing multiple prominent healthcare providers in antitrust claims against MultiPlan, Inc. and alleged co-conspirators for underpaying out-of-network reimbursements

  • Representing State Street Corporation in lawsuit brought by 13 state attorneys general concerning alleged conspiracy to cut coal production

  • Representing national real estate brokerage and regional real estate trade group in antitrust class actions alleging a conspiracy to force home-sellers and home-buyers to pay inflated sales commissions to real estate brokerages

  • Representing shale oil producer in multiple antitrust class actions alleging a conspiracy to decrease shale oil production

  • Representing one of largest producers of renewable energy in lawsuit filed by X Corporation concerning alleged advertiser boycott of X

  • Representing major university hospital system in antitrust litigation alleging conspiracy to limit employment opportunities of pharmacy residents

  • Representing financial services company in multiple state attorney investigations and Congressional investigation

  • Represented major retailer in internal investigation and government investigations related to sustainability and human capital initiatives and policies

  • Represented significant distributor in connection with internal investigation into alleged antitrust violations

  • Representing companies in multiple state attorney general and grand jury investigations into alleged antitrust violations

  • Represented energy client in internal investigation into antitrust criminal matters and related compliance issues

  • Obtained closure of antitrust grand jury investigation into one of world’s largest energy companies without any indictments

  • Obtained summary judgment and complete victory for client in In re Broiler Chicken Antitrust Litigation, 2023 WL 7220170 (N.D. Ill.)

  • Obtained dismissal with prejudice at motion to dismiss stage in JSW Steel (USA), Ltd. v. Nucor Corp. on behalf of United States Steel Corporation, which was affirmed on appeal by the Fifth Circuit Court of Appeals

  • Obtained summary judgment and complete appellate victory in In re Chocolate Confectionary Antitrust Litigation, 801 F.3d 383 (3d Cir. 2015) and Sterling Merchandising, Inc. v. Nestle S.A., 656 F.3d 112 (1st Cir. 2011)

  • Obtained dismissal of claims against multinational energy corporation direct-action cases, and state attorney general cases alleging that it engaged with other defendants in a decade-long conspiracy to bribe Venezuelan officials and rig bids for the sale and purchase of crude oil submitted to PDVSA, allegedly costing PDVSA billions of dollars in lost revenue; the trust was purportedly assigned the claims of PDVSA and the Venezuelan government so that it could litigate on PDVSA’s behalf in the U.S. courts

  • Represented multiple corporate client in non-public antitrust grand jury investigations and responses to civil investigative demands served by the U.S. Department of Justice and state attorneys general

  • Caused plaintiffs to abandon their claims following discovery on monopolization, attempted monopolization, and tying claims in Nestle Nespresso USA, Inc. v. Ethical Coffee Company, S.A.

  • Obtained dismissal of antitrust claims at motion to dismiss stage in Nirvana, Inc. v. Nestle Wates North America Inc.

  • Obtained rare denial of summary judgment for plaintiff in a “duty to deal” antitrust case alleging monopolization and attempted monopolization

  • Represented an elite college in class action alleging that highly-selective universities conspired to limit need-based financial aid paid to admitted undergraduate students

  • Represented multiple executives alleged to have conspired abroad to fix the prices of automotive parts destined for the US market

Credentials

Education

  • American University Washington College of Law, JD, cum laude, Mooer’s Trophy for Outstanding Student in Trial Advocacy; Journal of Sustainable Development Law and Policy (2007–2008), 2009
  • Georgetown University, BSFS, International Politics, 2006

Admissions

  • District of Columbia
  • Virginia
  • U.S. Supreme Court
  • U.S. Court of Appeals for the Third Circuit
  • U.S. Court of Appeals for the Fifth Circuit
  • U.S. Court of Appeals for the Eighth Circuit
  • U.S. Court of Appeals for the Ninth Circuit
  • U.S. Court of Appeals for the Eleventh Circuit
  • U.S. District Court for the District of Columbia

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Recognitions

  • Chambers USA, Antitrust: Litigation Specialists (District of Columbia), 2025 and 2026
  • Selected to the 500 Leading Litigators in America, Lawdragon, 2025 and 2026
  • Selected to the 500 Leading Global Antitrust & Competition Lawyers, Lawdragon, 2025 and 2026
  • Legal 500 U.S., Antitrust: Civil Litigation/Class Actions: Defense, 2023–2025
Insights

Client Alerts

Q2 2026 Healthcare Antitrust and Competition Update

The pace of policy initiatives, legislation, enforcement actions, and private litigation related to antitrust and competition in the healthcare sector …

August 24, 2026

August 24, 2026 • 14-minute read

Client Alerts

AI Antitrust Issues Checklist

As artificial intelligence (“AI”) transitions from a nascent technology into a central pillar of the global economy, public and private …

June 1, 2026

June 1, 2026 • 8-minute read

Client Alerts

Q1 2026 Healthcare Antitrust and Competition Update

The healthcare sector accounts for an increasingly significant component of the U.S. economy. Healthcare spending constitutes 18.0 percent of U.S. …

May 19, 2026

May 19, 2026 • 11-minute read

Articles

International Cartel Enforcement in 2026: Leniency as Both Sword and Shield

On March 25, 2026, at the 74th ABA Antitrust Law Spring Meeting, five leading competition enforcers from Brazil, Canada, the …

March 31, 2026

March 31, 2026 • 6-minute read

Articles

Litigating Tariff Refund Pass-On Class Actions: Lessons from Antitrust

Downstream purchasers—distributors, retailers, or end consumers—are now asking if they can claim a share of about $170 billion in potential …

March 25, 2026

March 25, 2026 • 1-minute read

News & Achievements