Xavier Oustalniol

Xavier Oustalniol is a Partner with StoneTurn in San Francisco. He focuses on complex forensic accounting issues, fraud investigations and prevention, and anti-corruption matters, and provides consulting services regarding damages analysis, securities class action litigations, arbitrations, accountant malpractice and purchase price disputes, including providing expert testimony.

With over 25 years of experience as an auditor, forensic accountant and litigation consultant, Xavier has worked with clients across a wide range of industries, including FinTech, banks (mortgage, retail, investment), insurance companies, investment companies, and other securities broker / dealers, as well as automotive, aviation, real estate, technology, energy, food, luxury apparel, chemicals, electronic components, gaming, telecom, broadcasting, professional services partnerships (including law firms), leasing, consumer products, agricultural business, manufacturing and transportation. Xavier has also assisted clients including the government and public defenders dealing with Ponzi scheme issues, False Claims Act and Qui Tam cases.

Xavier has testified as an accounting expert on the application of Generally Accepted Accounting Principles (“GAAP”) and other financial issues at trial, deposition and in arbitrations. He has authored expert reports, declarations and assisted with the preparation of experts for deposition and testimony. He also assisted counsel with deposition preparation of opposing experts and fact witnesses, and responses to Wells submissions.

He has assisted clients (debtors, creditors, trustees) in a number of bankruptcy-related litigations (including Enron, Lehman, Washington Mutual) and other accounting investigations, including during settlement negotiations and mediation.

Xavier has directed complex forensic accounting investigations for boards where regulators such as the U.S. Securities and Exchange Commission (“SEC”), U.S. Department of Justice (“DOJ”) and the Financial Industry Regulatory Authority (“FINRA”) were involved. He consulted on other cross-border disputes before the International Centre for Settlement of Investment Disputes (“ICSID”), the American Arbitration Association (“AAA”) and the International Chamber of Commerce (“ICC”), involving companies in Europe, South and Central America and Japan.

Prior to joining StoneTurn, Xavier was with Alvarez & Marsal, where he served as a Managing Director in the firm’s Global Forensic and Dispute Services practice in San Francisco. Previously, he was with two other global professional services firms. He began his career as an auditor with Deloitte.

Xavier is a Certified Public Accountant (licensed in the states of California and New York), Certified in Financial Forensics and a Certified Insolvency and Restructuring Advisor. He is fluent in French.

Turn to Xavier

StoneTurn’s culture is strong, ethical, and values honesty in interacting with others and helping both clients and employees to succeed.

Q: Clients say they look to StoneTurn to be a trusted adviser. Can you describe how we serve in that role?


Professionals and consultants always have a choice when it comes to how to work with clients. We can either respond to specific inquiries and requests and serve them on a “one-off” basis, or establish long-term relationships to not only provide the services they require, but also strategic insight as a frequent sounding board. It is clear StoneTurn prefers the latter approach and is viewed by its clients as a trusted adviser. We provide objective feedback and value our long-term relationships. We work alongside clients and view ourselves as an extension of their team. Clients know they can count on us and can pick up the phone whenever they need us. We work through the issues with clients and share our collective experience to give them the tools to succeed. In litigation, we assist sometimes from the complaint stage or from discovery through trial and help them navigate uncharted waters; we help focus on the issues that matter. During investigations, we keep clients abreast of developments at every turn, so they can adjust their strategy quickly to avoid surprises. We routinely involve other Partners to ensure our clients always have access to the right resources. In many ways, serving as a trusted adviser is only made possible through an emphasis on collaboration and StoneTurn’s culture.

Q: StoneTurn is known for being collaborative. Describe for us how the firm is able to work so seamlessly with clients and as colleagues.


StoneTurn’s professionals—starting with the Partners—care about clients and each other. We strive to provide exceptional service and value. We are passionate about finding the right answers and solutions to problems. This often means offering the best professionals (inside or outside the firm) for our clients, and requires us to identify and maximize the skills and expertise of all professionals in the firm. We do not believe in “gate keepers” who can get in the way of clients’ needs, and open, honest discussions. Simply put: We enjoy helping our clients and helping each other. I would say that our collaborative approach is contagious and our professionals thrive on it. I see it at work every day and it’s exhilarating. Collaboration ensures that our best resources and creativity are available to our clients even if they are not readily visible.

Q: Why is the culture at StoneTurn so important to you?


Culture defines individuals’ beliefs and how to interact and relate to others. It also determines the set of values by which a firm operates, wants to be recognized and, ultimately, its ability to succeed. StoneTurn’s culture is strong, ethical, and values honesty in interacting with others and helping both clients and employees to succeed. We “walk the talk,” we care, we empower others, and we respect each other and each other’s opinions and work/life balance. Many other organizations aspire to these ideals and sometimes they succeed; most times they claim they do, but more often than not, they fail. StoneTurn is a growing firm with a culture that inspires pride in its professionals. StoneTurn’s culture enables us to get better at what we do, and our success in turn benefits our clients.