"A strong reputation in the market across a range of… Dodd-Frank compliance work, as well as on M&A activity."
Legal 500 USA


Donald Waack is a partner in the Financial Services Regulatory & Enforcement practice of the Washington DC office. He counsels globally active financial services firms on their most challenging regulatory, transactional, and enforcement matters.

Don devotes the majority of his practice to advising banks, bank holding companies, and other financial institutions on complex strategic and regulatory matters, including investment authority issues and activities restrictions; regulatory capital; swap market regulation; affiliate transactions and lending limits; and proprietary trading and private fund restrictions arising under the Volcker Rule. He assists financial services clients with structuring significant investments and provides strategic advice and regulatory support for mergers and acquisitions and other complex transactions. Don also counsels hedge funds, private equity funds, and other firms regarding investments in the commercial banking sector and transactions with banks and other regulated counterparties. In connection with his regulatory counseling practice, Don works frequently with the staffs of the major federal and state bank regulatory agencies.

Don also advises domestic and non-US financial services firms in connection with sensitive internal investigations and similar matters. He counsels financial services clients on internal regulatory compliance reviews and has represented clients in connection with a broad range of regulatory inquiries and investigations, including federal and state enforcement matters.

Don was recently recognized as a “Rising Star” by IFLR1000 in the area of Financial Services Regulation. He joined Mayer Brown in 2008.


  • Anglais


Don’s recent representative engagements include the following:

  • Represented a large foreign banking organization before the Federal Reserve Board in connection with its review and remediation of BHCA compliance issues, including the restructuring and divestiture of non-conforming assets 
  • Represented a US hedge fund investor in a mid-sized bank holding company in connection with a Bank Holding Company Act “control” inquiry initiated by the Federal Reserve Board
  • Represented a large foreign banking organization in obtaining “financial holding company” status, at the time just the second such approval issued by the Federal Reserve Board following enactment of the Dodd-Frank Act and implementation of the US Basel III capital regime
  • Advised a large foreign banking organization with respect to its global review and remediation of merchant banking and other Bank Holding Company Act compliance issues
  • Advised a major US bank regarding regulatory and structuring issues related to $1.9 billion cross-border secured credit facility
  • Advised a major international banking organization on the development and implementation of a global Volcker Rule conformance plan, including analyzing investment and trading activities in US and non-US jurisdictions and developing a global compliance program 
  • Advised multiple foreign banking organizations in North America, Europe, Asia, and the Middle East with respect to the development and implementation of Volcker Rule conformance plans and compliance programs, addressing both proprietary trading and covered fund activities
  • Advised a large non-US swap dealer on developing and implementing a framework to satisfy US swap reporting obligations and other regulatory compliance requirements arising under Title VII of the Dodd-Frank Act
  • Advised a large non-US banking group regarding legal authority and structuring issues related to US real estate-related activities and investments
  • Advised a major US bank regarding strategic and regulatory issues arising in connection with the workout of a large portfolio of distressed loans secured by bank and bank holding company stock
  • Represented a large foreign banking organization in connection with the acquisition of a US asset manager and expansion of a US private wealth platform
  • Advised a major domestic bank in connection with its acquisition of the US banking operations of a large non-US banking organization
  • Represented sellers of a US regional bank and advised on regulatory matters related to restructuring of retained nonbank assets


Boston University School of Law, JD

Yale University, BA, with distinction

Inscriptions au Barreau


  • District of Columbia
  • Virginia (inactive)