Daniel J. Hay

DANIEL HAY represents individuals and corporations in all stages of complex and high-stakes litigation, including critical motions practice, oral argument, discovery, trial, and appeal. A member of Sidley’s Regulatory Litigation group, Daniel has extensive experience representing clients in challenges to federal and state agency actions, government enforcement actions, and commercial disputes in highly regulated industries. He also frequently represents clients in complex First Amendment and constitutional disputes.

Daniel is also an experienced litigator in the emerging space of legal sports betting and gaming law. He has advised numerous companies in diverse industries on navigating federal and state gaming laws in the wake of the Supreme Court’s decision in Murphy v. NCAA. Daniel’s clients in this space have included legal sportsbooks, fantasy sports operators, cryptocurrency companies, commodities exchanges, lottery vendors, and others.

Daniel joined Sidley following a clerkship with Judge Steven Colloton of the U.S. Court of Appeals for the Eighth Circuit. Prior to his clerkship, Daniel completed a D.C. Bar Association Pro Bono Fellowship at the Becket Fund for Religious Liberty, where he represented religious nonprofits in constitutional cases before the federal courts of appeals.

Daniel received his law degree from Vanderbilt University Law School, where he was a John W. Wade Scholar and served as editor in chief of the Vanderbilt Law Review. Before attending law school, Daniel worked as a middle school math teacher with Teach for America and an aide to a member of Congress.

Daniel frequently represents clients in litigation against government agencies and in commercial disputes in highly regulated industries. Daniel’s recent and ongoing representations include:

Trial & Litigation Matters

• Serving as lead counsel to a leading dietary supplement labeler in multiple putative nationwide class actions asserting false and deceptive advertising practices.
• Representing a multinational ecommerce company in a series of related commercial litigations concerning its reverse logistics operations.
• Successfully represented Microsoft as part of a trial team against the FTC’s attempt to block Microsoft’s $68.7 billion acquisition of video game publisher Activision, which was described by the trial court as “one of the largest, if not the largest, tech industry mergers.”
  
• Representing a leading cloud, AI, and web server company in regulatory challenges concerning the development of multi-billion dollar data centers.
• Representing an out-of-home advertising company in a high-stakes force majeure dispute arising out of the COVID-19 pandemic.
• Successfully represented Clear Channel in obtaining summary judgment in complex Takings, First Amendment, preemption, and breach of contract challenge to a local government ordinance.
• Representing a major global technology company on charges of racketeering, trade secret theft, bank fraud, and other alleged offenses.
• Successfully represented a government national security contractor in obtaining a judicial override of a stay of performance of a contract illegally awarded to a competitor.
• Represented a Fortune 500 financial services/FinTech company in a deceptive advertising and unfair business practices case brought by the Federal Trade Commission.
• Represented a major telecommunications company in connection with litigation over subpoenas issued by the U.S. House Select Committee on the January 6 Attack.
• Represented a global pharmaceutical manufacturer in a multifaceted Lanham Act case in the U.S. District Court for the Northern District of California, the U.S. Court of Appeals for the Ninth Circuit, and the Judicial Panel on Multidistrict Litigation.

Appellate Matters

• FTC v. Microsoft Corp., 136 F.4th 954 (9th Cir. 2025): Successfully obtained affirmance of a trial court order denying the FTC’s request to block Microsoft’s acquisition of Activision.
• Ford v. TD Ameritrade, Inc., 115 F.4th 854 (8th Cir. 2024): Successfully represented broker-dealer in overturning class certification order in a securities fraud class action in a suit arising out of the intersection between the duty of best execution, order routing and high-frequency trading. The Sidley team was named a runner up for Am Law’s “Litigator of the Week” for this victory.
• NCFA v. Blinken, 4 F. 4th 106 (D.C. Cir. 2021): Successfully argued and briefed a challenge to agency guidance documents, which the D.C. Circuit unanimously vacated on the grounds that the guidance imposed new legislative rules without notice and comment. Daniel also persuaded the D.C. Circuit to reverse the district court’s ruling that our client lacked associational standing.
• NYSDEC v. FERC, 991 F.3d 439 (2d Cir. 2021) and National Fuel Gas Supply Corp. v. NYSDEC, 761 F. App’x 68 (2d Cir. 2019): Successfully represented an energy company in a pair of petitions for review concerning our client’s authority to construct a federally approved natural gas pipeline. Law360 awarded the Sidley team its “Legal Lion of the Week” title for this victory.
• United States of America v. AT&T, 916 F.3d 1029 (D.C. Cir. 2019): Successfully represented AT&T in the government’s appeal of the district court decision allowing AT&T to merge with Time Warner. The Wall Street Journal described this decision as “cement[ing] one of the biggest losses for the Justice Department’s antitrust division in a generation.”
• Mallory v. Norfolk Southern Railway Co., 600 U.S. 122 (2023): Represented respondent in Supreme Court merits case regarding the validity of statutes mandating consent to general personal jurisdiction.
• Biden v. Nebraska, 143 S. Ct. 2355 (2023): Amicus counsel to a coalition of former government officials, including former attorneys general and OMB directors, in a high-profile challenge to the executive action forgiving student debt.
• Murphy v. NCAA, 138 S. Ct. 1461 (2018): Authored an amicus brief on behalf the American Gaming Association (AGA), arguing that the Professional and Amateur Sports Protection Act, a federal law that effectively prohibited sports betting in most states, violated the Tenth Amendment and enabled a massive, unregulated black market. In a 7-2 decision citing Sidley’s brief, the Supreme Court agreed and held states were allowed to decide for themselves whether to legalize sports betting.
• IGT PLC v. Garland, 628 F. Supp. 3d 393 (D.R.I. 2022) and New Hampshire Lottery Commission v. Rosen, 986 F.3d 38 (1st Cir. 2021): Represented International Game Technology (IGT), one of the world’s largest lottery and casino gaming companies, as amicus and successfully challenged the Department of Justice’s reinterpretation of the Wire Act to reach non-sports betting. The U.S. Court of Appeals for the First Circuit affirmed a declaratory judgment in favor of another lottery company, but vacated farther-reaching relief that would have provided IGT freedom to operate. IGT then sued in the U.S. District Court for the District of Rhode Island, seeking a declaratory judgment that its nationwide non-sports betting operations were not subject to the Act. The Court granted summary judgment in favor of IGT, rejecting the government’s argument that IGT lacked standing because its risk of prosecution was not sufficiently imminent.

Regulatory Counseling

Daniel also regulatory advises companies on the application of new laws and regulations, particularly in the area of gaming, consumer protection, and unfair competition. Recently, Daniel has advised multiple companies in litigation, regulatory compliance, and congressional inquiries regarding the INFORM Consumer Act, a recently enacted law regulating ecommerce platforms.

Daniel is a past president of the board of directors of the Hemophilia Association of the Capital Area.

Daniel maintains an active pro bono practice on behalf of nonprofits, religious organizations, and individual civil rights plaintiffs.

He has appeared as counsel in numerous religious liberty and First Amendment cases, including:

• Successfully representing a Hassidic Jewish organization in a challenge to a local government’s decision to seize the client’s house of worship through eminent domain. The litigation resulted in a multi-million dollar settlement for the organization and a federal consent decree ensuring the organization could use its house of worship free from further interference.
• Successfully representing a Roman Catholic diocese at trial and on appeal against an eight-figure defamation claim brought by a suspended priest.
• Supervising numerous briefs in the U.S. Supreme Court and U.S. Court of Appeals on behalf of religious nonprofits in connection with the Yale Law School Free Exercise Clinic.

Daniel is currently serving as lead counsel in a putative class action in the District of the District of Columbia, challenging the Army’s retirement benefits classification of soldiers who were medically retired following exposure to burn pits.

Daniel has also been appointed as counsel by several appellate courts to represent indigent parties. These appointed representations include:

• Parker v. District of Columbia, 298 A.3d 785 (D.C. 2023), in which D.C.’s high court vacated the defendant’s convictions for armed robbery and possession of a firearm during a crime of violence.
• United States v. Helm, 58 F.4th 75 (2d Cir. 2022), which challenged the government’s conduct at sentencing and the district court’s application of the sentencing guidelines.
• Tolliver v. Noble, 752 Fed. App’x 254 (6th Cir. 2018), which reinstated an inmate’s challenge to prison officials’ allegedly retaliatory confiscation of his legal materials.

Additionally, Daniel was part of a trial team that secured a jury award of compensatory and punitive damages in a federal civil rights case alleging unconstitutionally excessive force in effecting arrest, and obtained compassionate release on behalf of a federal prisoner whose underlying health conditions placed him at serious risk from COVID-19.