Mallory Tosch Brennan is a partner in the Litigation practice at Shearman & Sterling LLP.

She focuses on representing global corporations and financial institutions in mergers and acquisitions litigation and transactional disputes, securities litigation, and other complex commercial disputes, including bankruptcy and antitrust actions. She also has experience counseling multinational corporations in connection with both internal and regulatory investigations.

Mallory has been ranked by Chambers USA in 2022 and 2023 for Securities Litigation. Mallory has been recognized by The Legal 500 as a Next Generation Partner for M&A Litigation: Defense from 2017 – 2023. In 2018, 2019, and 2020 Mallory was named to the Benchmark Litigation 40 & Under Hot List. She has also been named a “Rising Star” by the New York Law Journal and the Euromoney Legal Media Group. 

M&A Litigation

• Represent corporates in M&A transactions on both the buy-side and sell-side, as well as financial institutions advising on M&A transactions, including in shareholder class actions, busted deals, post-transaction disputes, and regulatory inquiries:
  
  • Pattern Energy Group in litigation arising out of its acquisition by CPPIB
  • Intercontinental Exchange Inc. (ICE) in litigation arising out of its acquisition of Black Knight
  • Microvast Holdings Inc. in litigation arising out of its deSPAC transaction with Tuscan
  • A large investment bank in connection with a Special Litigation Committee investigation into defense advisory services to a client facing an activist investor campaign
  • A large investment bank in connection with the Alta Mesa deSPAC
  • A large private equity oil & gas investor in midstream assets in various disputes, including with LLC co-owners and with a joint venture purchaser
  • A midstream oil & gas company in a post-closing earnout dispute
  • Liberty Global in connection with an action relating to the acquisition of Sunrise
  • A large investment bank in connection with litigation challenging a founder’s interests in a subsidiary
  • Raytheon in the United Technologies merger
  • Goldman Sachs in litigation arising out of the sale of Saks Fifth Avenue
  • LyondellBasell in the A. Schulman acquisition
  • Liberty Global in connection with litigation arising out of the Liberty Broadband acquisition of Charter Communications
  • Capital Square Partners in the Aegis/Startek acquisition
  • CVS in the Aetna acquisition
  • Altice in the Cablevision acquisition
  • Dassault in the Exa acquisition
  • WebMD Health Corporation in its acquisition by Internet Brands, a portfolio company of Kohlberg Kravis Roberts & Co. L.P. (KKR)
  • Pall in its acquisition by Danaher
  • Daimler AG in connection with various Chrysler-related post-demerger litigations and disputes
  • Huntsman Corp. in a merger dispute with Hexion Chemicals Corp.
  • Merrill Lynch in connection with shareholder litigation arising out of its merger with Bank of America
  • BCE Inc. against former subsidiary of Teleglobe Inc.

Securities-Related Litigation

• A large telecom company in multiple litigations challenging various disclosures made in securities filings
• Altice USA and related entities and individuals in securities litigation arising out of IPO and in connection with Section 16(b) claims
• Jefferies in a securities litigation related to the acquisition by Landcadia Holdings, Inc., a special purpose acquisition company (“SPAC”), of Waitr Holdings, Inc.
• Orbital ATK in securities litigation arising out of financial restatement
• Underwriting syndicates, including clients such as Bank of America, Citigroup, Merrill Lynch, Credit Suisse and dozens of others, in separate securities class actions arising out of recent stock offerings of companies such as ZTO Express and Arconic
• Countrywide and related entities in ongoing institutional RMBS purchaser actions filed in state and federal courts across the United States by institutional plaintiffs such as federal home loan banks, mutual and hedge funds, insurance companies and regional banks
• Barclays in the FHLBS RMBS litigation
• Countrywide with respect to litigation concerning CDOs
• Todd Newman, former portfolio manager at Diamondback Capital, in connection with the reversal of his insider trading conviction

White-Collar and Regulatory Investigations

• Experience in conducting internal investigations into corporate governance irregularities, insider trading, FCPA violations, and other regulatory matters
  • A major international financial institution in an internal investigation into mutual fund investment irregularities at a Mexican subsidiary, including potential insider trading and related internal governance issues
  • An international engineering and construction company in a criminal investigation by the United States Department of Justice for possible FCPA violations
  • Former executives of the South American subsidiary of a multinational company in connection with an FCPA investigation and a potential criminal investigation by local authorities
  • Employee of foreign automotive manufacturer in connection with investigation by U.S. authorities into potential regulatory, criminal, and antitrust violations

Antitrust Litigation

• Experience representing financial institutions and corporations in benchmarking class actions and other antitrust litigation
  • A defense intelligence contractor in a no-poach antitrust class action
  • A financial institution in the Mexican Government Bonds antitrust class action
  • A financial institution in the ISDAFIX antitrust class action
  • A financial institution in a class action asserting violations of the Commodity Exchange Act and antitrust laws related to Yen LIBOR and TIBOR
  • A major European cargo airline in a criminal price-fixing cartel investigation and the follow-on federal class action lawsuit and related opt-out actions alleging a conspiracy to fix the prices of air cargo

Additional Complex Commercial Experience

• A startup hydrogen company in a breach of contract litigation with a services provider
• Citigroup in a class action concerning purported misconduct in Mexico
• Shorenstein Properties in connection with a commercial property dispute
• Deutsche Bank in a foreclosure litigation in connection with a distressed hotel property

Professional Affiliations

• Board of Directors, French American Chamber of Commerce - Texas 
• Board of Directors, American Association for the International Commission of Jurists 
• Member, New York State Bar Association

Awards & Accolades

• Recognized by Chambers USA as Up & Coming in Securities Litigation - Texas (2022-2023)
• Recognized by The Legal 500 as a "Next Generation Lawyer" for M&A Litigation Defense (2017-2023)
• Named "Top Ten Most Influential Securities Litigation Lawyers in Texas" by Business Today (2023)
• Named to the Benchmark Litigation "40 & Under Hot List" (2018-2020)
• Named a "Rising Star" by the New York Law Journal 
• Name a "Rising Star" by the Euromoney Legal Media Group

Publications

• Co-author, “Delaware Court of Chancery Rejects Claims Related to the Acquisition of an Alleged Controller’s Portfolio Company for Failure to Plead Demand Futility,” The M&A Lawyer, February 2024
• Co-author, “6 Focus Areas For Companies Managing The Risks Of AI Use,” Law360, January 2024
• Co-author, “Delaware Court of Chancery Rejects Stockholder Demand for Corporation to Supplement Its Section 220 Production with Searches and Production of Email,” The M&A Lawyer, October 2023
• Co-author, “Delaware Court of Chancery Holds That Corwin Cleansing Does Not Apply to Claims for Injunctive Relief Related to Alleged Defensive Measures,” The M&A Lawyer, June 2023
• Co-author, “Delaware Court of Chancery Dismisses Breach of Contract Claims Against Buyer, Finding Seller Retained Post-Closing Liability Related to Certain Product-Liability Litigations,” The M&A Lawyer, May 2023
• Co-author, “Delaware Court of Chancery Grants Plaintiff Attorney's Fees Award Under Corporate Benefit Doctrine for Demand to SPAC Board Leading to Adjusted Voting Structure in Connection with Merger,” The M&A Lawyer, February 2023
• Author, “Delaware Court of Chancery Finds Personal Jurisdiction Over LLC “Acting Manager” in Post-Closing Investor Action Challenging Merger with SPAC,” The M&A Lawyer, November/December 2022
• Author, “Delaware Supreme Court Reverses Dismissal of a Post-Merger Suit for Alleged Breach of Fiduciary Duty Related to Disclosures on Appraisal Rights, The M&A Lawyer, August 2022
• Author, “Finding That Allegedly Conflicted Acquisition Satisfied Entire Fairness Review, Delaware Court of Chancery Rejects Breach of Fiduciary Duty Claims,” The M&A Lawyer, June 2022
• Author, “Delaware Court of Chancery Rejects Motion to Stay SPAC Breach of Fiduciary Duty Suit Pending Parallel Federal Securities Action,” The M&A Lawyer, April 2022 
• Co-author, “Considerations in Venture Capital and M&A Transactions in the AI Mobility Industry,” Global Legal Insights to: AI, Machine Learning & Big Data 2019, Spring 2019
• Author, “Lorenzo v. SEC: Potential Implications for Private Rights of Action,” State Bar of Texas: The Newsletter of the Corporate Counsel Section (Volume 1, Issue 2), Spring 2019

Speaking Engagements

• Co-Presenter, “The Evolving Landscape of ESG Litigation,” University of Texas School of Law The Review of Litigation Symposium: The ESG Legal Landscape, February 16, 2024
• Presenter, “When the Deal Goes Wrong,” Practicing Law Institute, January 10, 2024
• Co-Presenter, “Harnessing the Potential of Artificial Intelligence While Ethically Managing the Risks,” Leading Investment Management Firm, October 3, 2023
• Co-Presenter, “Social Media and AI – Ethical Guidelines for Lawyers," Texas General Counsel Forum, May 16, 2023
• Panelist, “Taking & Defending Powerful Depositions,” The Rossdale Group, July 29, 2020