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Securities Enforcement & Litigation

Whether you are a public company, a fund, or an entity required to disclose financial information, Arnold & Porter's Securities Enforcement & Litigation attorneys have led marketing-leading corporations and the individuals at the helm in “bet-the-company” securities-related issues spanning litigation, enforcement, corporate governance, compliance counseling, and investigations. Our team is a one-stop shop for private companies and public issuers, financial institutions, life sciences  companies, start-ups and tech giants alike, and executives, boards of directors, and special committees – including those navigating the evolving securities impact and landscape around AI. Together, we carry forward a tradition of excellence that dates to the founding of our practice by one of the authors of the seminal SEC antifraud provision, Rule 10b-5.

  • Proactive Compliance Counseling: We provide public and private issuers, and boards of directors and board committees proactive compliance, risk management and due diligence advice, both before and after securities-related issues arise.

  • Deftly Navigating Internal and Governmental Investigations: Our team is skilled at navigating complex internal investigations and defending against inquiries by the SEC, DOJ, state Attorneys General, PCAOB, and FINRA, with a focus on mitigating enforcement and litigation risk.

  • Defending Securities Litigation: We defend the full spectrum of securities litigation – shareholder derivative suits, class actions, IPO, M&A, insider trading, and private equity disputes, through to insurance, professional liability, and clearing and brokerage matters, including actions by state Attorneys General.

“Arnold & Porter does a very good job of thinking five steps ahead. They’re responsive, responsible, and are strategic thinkers.” – (client) Chambers USA 2026
“Arnold & Porter provides one-stop-shop service to clients across a myriad of private securities class actions, as well as accompanying regulatory probes in tightly regulated sectors.” – Legal 500 United States 2025
Securities Enforcement & Litigation Practice Is Recognized by Chambers USA 2026
Chambers USA Top Ranked 2026 logo
“Arnold & Porter’s team masters not only the law and facts of a case but also establishes a deep understanding of the industry in which its clients operate.” – (client) Chambers USA 2026

Experience Highlights

  • Private companies and public issuers in navigating securities-related issues arising from the Trump administration’s Executive Orders.

  • National accounting firm in investigations by the SEC and PCAOB involving auditor independence relating to the performance of non-audit services for audit clients and accounting firm entity theories of liability, and voluntary requests for information in SEC sweep of the accounting industry.

  • Yelp and three of its senior officerin defeating a 10b-5 securities class action in the Northern District of California arising from allegations related to the company's revision of forward-looking guidance and related disclosures.

  • Special board committee of a financial services public company both in conducting an internal investigation involving corporate governance, internal control and financial reporting issues, and in handling related SEC, DOJ, and other regulatory investigations and shareholder litigation.

  • Independent directors of American Realty Capital-Retail Centers of America in successful defense of a securities class action in the U.S. District Court for the District of Maryland arising out of the merger of two REITs with combined assets of $3.5 billion.

  • JPMorgan Chase in successful defense and appeal of Sarbanes-Oxley whistleblower case.

  • Dunkin' Brands in investigation, litigation, and favorable settlement of a New York Attorney General’s lawsuit alleging the failure to protect consumer data security and privacy.

  • International consulting firm in an SEC investigation in which valuation and disclosure issues of a public issuer client are at issue. 

  • Software company in an SEC inquiry stemming from a cyberattack; following multiple attorney proffers, the SEC declined to pursue enforcement action.

  • Special committee of the board of directors of a multinational publicly traded financial services company in an internal investigation involving whistleblower issues and breaches of duty relating to AML and fraud compliance. The investigation follows a series of settlements between the company and government regulators, including the state Attorney General, DOJ, and FTC.

  • Coherus BioSciences in the strategic acquisition of Surface Oncology and in connection with threatened shareholder litigation concerning merger disclosures.

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Recognition

  • Chambers Global
    Investigations & Enforcement (International & Cross-Border) (USA) (2021-2026)
  • Chambers USA
    Auditor & Accountant Liability (Nationwide) (2025-2026)
    Corporate Crime & Investigations: The Elite (Nationwide) (2015-2026)
    Financial Services Regulation: Banking (Enforcement & Investigations) (Nationwide) (2006-2026)
    Securities: Regulation: Enforcement (Nationwide) (2010-2023)
  • The Legal 500 US
    Securities Litigation: Defense (2014-2026)
    Insurance: Advice to Insurers (2024-2026)
    General Commercial Disputes (2015-2026)
  • BTI Consulting Group
    Class Action Powerhouses (2025-2026)
    Gen AI Litigation Leaders (2026)
    Intimidating Opponent in Litigation (2023-2026)
  • Best Law Firms Ranked by Best Lawyers
    Litigation – Securities (National) (2011-2024)
    Litigation – Securities (Washington, D.C.) (2011-2024)
    Litigation – Regulatory Enforcement (SEC, Telecom, Energy) (National) (2011-2024)