John Teolis is a Partner in the Financial Services Group. His practice includes corporate, commercial and consumer finance, banking, financial institution regulation, mergers and acquisitions (particularly involving financial services entities), money transmission, information processing and payment processing. John is involved in most legal matters involving financial institutions. He has acted as counsel to several Canadian and non-Canadian entities that have established a banking, commercial, consumer or other financial presence in Canada and for companies that have established a payment processing or information processing business in Canada.

John is listed in Law Business Research's Who's Who Legal: Canada 2010. He is also included in Chambers Global: The World's Leading Lawyers for Business (banking) and is acknowledged as having built up an "'awesome reputation' in the regulatory field [and] has an intimate understanding of clients' needs." He is recognized by The Canadian Legal Lexpert Directory and The Lexpert/American Lawyer Guide to the Leading 500 Lawyers in Canada as a leading practitioner in the banking field. He is noted as consistently recommended in The Canadian Legal Lexpert Directory 2010. John is listed in Law Business Research's The International Who's Who of Business Lawyers 2010 (banking) and was nominated by his peers to be listed in Law Business Research's The International Who’s Who of Banking Lawyers 2010 as one of the world’s leading practitioners in this field. He is also listed in Legal Media Group's Guide to the World's Leading Banking Lawyers. John is listed as a "leading lawyer" in the finance and banking sectors in IFLR1000: The Guide to the World's Leading Financial Law Firms. In The Best Lawyers in Canada 2008, John was voted by peers as one of the leading banking lawyers in Canada. John is also on the board of advisers of the Morin Center for Banking and Financial Law at Boston University. He is the first non-American to be elected to the board of advisers.

John is the former co-chair of the Banking Committee of the International Bar Association. He serves on the advisory boards of various publications, including the International Financial Law Review. He is also a director of numerous corporations, the chairman of The Arthritis & Autoimmunity Research Centre Foundation and a member of the Finance and Audit Committee of the University Health Network.