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Marisa O'Sullivan


Marisa O’Sullivan is a problem solver. Clients count on Marisa to distill complex problems, deliver usable advice, and achieve outstanding results. Her ability to identify pressure points and negotiate advantageous resolutions has allowed her to skillfully advocate for her clients over the course of her career.

Marisa’s practice focuses on insurance recovery for commercial policyholder clients. She provides smart, pragmatic, business-focused advice and counsel on insurance and risk-transfer issues like:

  • Handling large-scale insurance-coverage litigation or arbitration to maximize insurance recovery;
  • Analyzing insurance programs or individual policies to identify holes or overlaps in coverage, make policy recommendations, and accomplish risk transfer objectives;
  • Scrutinizing the interplay between the client’s insurance policies, the policies maintained by vendors and contractors, and the insurance and indemnity provisions in contracts;
  • Addressing additional-insured issues;
  • Assisting in the preparation and presentation of complex claims and proofs of loss;
  • Providing strategic advice and recommendations related to insurance-coverage issues; and
  • Interfacing with insurers to facilitate the resolution of claim disputes prior to litigation.

From the outset of any project, Marisa evaluates the client’s ultimate objectives and works to achieve them, whether through favorable contractual terms, preferable resolution of a claims-track dispute, or settlement of coverage litigation. She has spent her career immersed in insurance coverage and is frequently asked to write and speak on insurance topics, garnering several peer-nominated awards for her professional achievements. Marisa’s depth of experience in insurance recovery and long-standing reputation within the practice area produce credibility that insurers respect, which often allows her to secure the favorable outcome clients want.

In particular, Marisa has a wealth of experience with cyber insurance and related cyber risks. She is adept at providing cutting-edge advice and counsel on coverage for security breaches, system failures, privacy events, and reputational damage. As cyber concerns recur in the nightmares of corporate leadership everywhere, Marisa provides steady guidance on risk management and claim response to weather the storm.

Outside of her work for clients, Marisa is consistently recognized by her colleagues and peers for her leadership in the Dallas legal community. Named by the Dallas Association of Young Lawyers (DAYL) Outstanding Young Lawyer of the Year in 2019, Marisa is a DAYL Foundation and Dallas Bar Association (DBA) Foundation Fellow, and currently serves on the boards of the DBA and Dallas Women Lawyers Association. She is slated to serve as President of the Dallas Women Lawyers Association in 2022.


Litigation Experience

Represented a travel technology company in coverage litigation against its commercial general liability and errors and omissions insurers to recover $90 million in policy limits for the defense and settlement of an antitrust lawsuit; settled after a favorable ruling on motion for summary judgment.

Represented a national seafood distributor in high-stakes coverage litigation to secure reimbursement for an eight-figure inventory loss.

Engaged by a national alarm monitoring company as insurance coverage counsel in negotiations to settle a class action MDL seeking $40 billion in damages for violations of the Telephone Consumer Protection Act; represented the client in resulting coverage litigation against cyber and commercial general liability insurers in Texas and West Virginia; ultimately negotiated separate settlements with each insurer, including complex indemnity provisions.

Represented a bar and restaurant in securing coverage for a multimillion-dollar personal injury claim; secured a summary judgment on the duty to defend and 100% insurer-funded settlement of the underlying case.

Represented a publicly traded heating, cooling, and refrigeration manufacturer in coverage litigation against its first-layer excess insurers related to a $100 million insurance program providing coverage for a nationwide asbestos docket; ultimately negotiated a favorable cost-sharing agreement with the excess carriers.

Represented an aerospace manufacturer in coverage litigation against its commercial property insurers for $30+ million in business interruption losses resulting from hurricane-related flooding.

Claim Negotiation + Advice Experience

Advised an international retailer on coverage issues to favorably structure a business income loss claim under a commercial property policy for losses sustained by its Puerto Rico properties following Hurricane Maria.

Completed a comprehensive cyber policy analysis for an airline client, including a comparison of 30+ risk scenarios against cyber policy language and recommendations to resolve gaps in policy language.

Engaged by a global telecommunications technology company to challenge denials from cyber, commercial general liability, and directors and officers insurers for defense costs related to a series of high-stakes patent infringement and unfair competition lawsuits; secured insurer payment of millions in defense costs without coverage litigation.

Completed a cyber insurance program assessment for a governmental entity, including participation in risk roundtables with engineering, IT, marketing, and operations department heads to identify risks; analyzed insurance and indemnity requirements in cybersecurity vendor contracts; and made recommendations to client and broker teams regarding cyber policy language.

Advised a Fortune 500 retailer on coverage issues under cyber and commercial general liability policies (both as a named insured and as an additional insured) in connection with a multistate MDL consumer class action; analyzed class action settlement insurance policy; and challenged the insurers’ coverage positions on various issues.

Engaged by multiple real estate developer clients to assist with claims track negotiation related to business income losses and large-scale property damage due to flooding, winter storm damage, fire, and COVID-19-related losses.


Southern Methodist University, Dedman School of Law
J.D., cum laude, 2012
Chief Counsel for the W.W. Caruth Child Advocacy Clinic, Fall 2011
Jackson Walker Moot Court, Board Member

University of Missouri, University Honors Program
B.A., magna cum laude, 2009
Study Abroad Exchange, University of Manchester, United Kingdom, Spring 2008
Study Abroad, Ghana, West Africa, Winter 2007

Court Admissions

State Bar of Texas

United States District Court for the Eastern District of Texas

United States District Court for the Northern District of Texas

United States District Court for the Western District of Texas


Dallas Association of Young Lawyers

  • Board Member, 2017-2020
  • Member, 2012 to present
  • Leadership Class and Project Steering Committee Member, 2015-2016
  • Membership Chair, 2012-2015

Dallas Women Lawyers Association

  • President-Elect, 2021
  • Board Member, 2017 to present
  • Mentoring Circles Steering Committee Co-Chair, 2015 to 2019

Dallas Women Lawyers Association Foundation

  • Board Member, 2021 to present

Dallas Bar Association

  • Board Member, 2021 to present
  • Trial Skills Section, Board Member, 2015-2016
  • Tort and Insurance Practice Section, Board Member, 2015-2016

National Women Lawyers Association

  • Dallas Conference Steering Committee Member, 2017-2018

Junior League of Dallas, Member, 2014-2017

Honors and Distinctions

Selected as a Texas Rising Star by Super Lawyers, as published by Thomson Reuters (2018-2021)

Named one of the Best Lawyers in Dallas in Insurance Law by D Magazine (2021)

Named one of the Best Lawyers in Dallas Under 40 by D Magazine (2019-2021)

Named Outstanding Young Lawyer by the Dallas Association of Young Lawyers (2019)

Selected by the Dallas Association of Young Lawyers as One to Watch (2016)

Dallas Association of Young Lawyers Foundation Fellow

Dallas Bar Association Foundation Fellow


Solving Cybersecurity: How to Help Your Client Navigate the Minefield, panel presentation to Dallas Association of Young Lawyers, In-house Counsel CLE, Dallas, Texas, August 2019.

Nuts & Bolts: Directors & Officers Liability Policies, article for Journal of Texas Insurance Law, Volume 15, Number 1, August 2017.

Insurance 101: What Every Young Lawyer Should Know, presentation for Dallas Association of Young Lawyers, Dallas, Texas, November 2016.

E-Discovery: What it Means to Us, article for TYLA eNews, a Texas  Young Lawyers Association publication, April 2016.

E-Discovery Outsourcing, presentation for Global Society class, Sociology Department, Southern Methodist University, Dallas, Texas, November 2015.

Mistakes in Corporate Insurance: The Top 10, article for Headnotes, a Dallas Bar Association publication, June 2015.

E-Discovery Outsourcing, presentation for Global Society class, Sociology Department, Southern Methodist University, Dallas, Texas, April 2015, November 2014, and April 2014.

The Skinny on Dodd-Frank for Insurance Counsel, article for Consultant’s Corner for InsideCounsel.com, February 2015.

The Top Ten Corporate Insurance Pitfalls for Counsel to Avoid, article for Consultant’s Corner for InsideCounsel.com, January 2015.

Taking Inventory: An Overview of Corporate Liability Insurance, article for Consultant’s Corner for InsideCounsel.com, December 2014.