Argued February 8, 2024 Decided November 22, 2024

No. 23-5129

ALPINE SECURITIES CORPORATION, APPELLANT

v. FINANCIAL INDUSTRY REGULATORY AUTHORITY AND UNITED STATES OF AMERICA, APPELLEES

Appeal from the United States District Court for the District of Columbia (No. 1:23-cv-01506)

Brian W. Barnes argued the cause for appellant. With him on the briefs were Maranda E. Fritz, David H. Thompson, and Athanasia O. Livas.

William P. Barr, Noel J. Francisco, Brian C. Rabbitt, and Anthony J. Dick were on the brief for amicus curiae American Free Enterprise Chamber of Commerce in support of appellant.

Russell G. Ryan and Andrew Morris were on the brief for amicus curiae New Civil Liberties Alliance in support of appellant. 2 Carrie Devorah, pro se, was on the brief for amicus curiae Carrie Devorah in support of appellant.

Amir C. Tayrani argued the cause for appellee Financial Industry Regulatory Authority. With him on the brief were Alex Gesch and Max E. Schulman.

Joseph F. Busa, Attorney, U.S. Department of Justice, argued the cause for intervenor appellee United States. With him on the brief were Brian M. Boynton, Principal Deputy Assistant Attorney General, and Mark B. Stern and Courtney Dixon, Attorneys. Gerard J. Sinzdak, Attorney, entered an appearance.

Zachary Knepper was on the brief for amicus curiae North American Securities Administrators Association, Inc. in support of appellees.

Alan L. Rosca was on the brief for amicus curiae Public Investor Advocate Bar Association in support of appellee.

Adam G. Unikowsky, Elizabeth B. Deutsch, and Arjun R. Ramamurti were on the brief for amici curiae National Futures Association, et al. in support of appellee.

David S. Flugman was on the brief for amicus curiae Benjamin P. Edwards in support of appellee.

Adam L. Deming, Mark D. Harris, and Margaret A. Dale were on the brief for amici curiae the Depository Trust Company, et al. in support of appellees.

Kevin King and Daniel G. Randolph were on the brief for amicus curiae Securities Exchanges in support of appellee. 3 Pratik A. Shah and Lide E. Paterno were on the brief for amicus curiae Horseracing Integrity and Safety Authority, Inc. in support of appellee.

Jonathan E. Barbee and Robert K. Kry were on the brief for amicus curiae Municipal Securities Rulemaking Board in support of neither party.

Before: SRINIVASAN, Chief Judge, MILLETT and WALKER, Circuit Judges.

Opinion for the Court filed by Circuit Judge MILLETT.

Opinion concurring in the judgment in part and dissenting in part filed by Circuit Judge WALKER.

MILLETT, Circuit Judge: The United States securities industry is regulated by both private entities and the federal government. These private regulators, referred to as self- regulatory organizations, date back centuries to when groups of securities traders adopted self-governing rules by which they would conduct business and ensure public trust in their operations.

Today, a private corporation, the Financial Industry Regulatory Authority (“FINRA”), regulates and oversees large parts of the securities industry. Congress, however, has overlain federal law on those private self-regulatory practices. As relevant here, federal law effectively requires most firms and individuals that trade securities to join FINRA as a condition of engaging in that business. Federal law, in turn, subjects FINRA to oversight by the Securities and Exchange Commission (“SEC”) and requires that FINRA ensure that its members comply both with FINRA’s own rules and with federal securities laws. 4 In 2022, FINRA sanctioned one of its members, Alpine Securities Corporation, for violating FINRA’s private rul