Atty. Willie Santiago is both a Lawyer and Certified Public Accountant.

He is currently the Director of Tax & Corporate Services Division of Diaz Murillo Dalupan & Company.

He is a regular lecturer at Philippine Institute of Certified Public Accountants (PICPA) National Office, Association of Certified Public Accountants in Public Practice (ACPAPP), Asian Institute of Taxation, and Mandatory Continuing Legal Education (MCLE) for Lawyers at Alternative Center for Continuing Education and Seminar Solutions, Inc. (ACCESS).

He is also invited to speak at Institute of Internal Auditors, University of Asia and the Pacific, Philippine Retailers Association, Philippine Association of Management Accountants and various chambers of commerce.

With his 20 years of experience in public practice engaged in business registration and formation, tax advocacy and controversy, and mergers and acquisitions, he has already handled numerous engagements from small to medium-size and multi-national companies registered with the Board of Investments and Philippine Economic Zone Authority.

His exposure includes non-stock non-profit organizations, charter flights/airline, club shares, property management companies, brokerage, and call centers.

Atty. Willie represents clients before SEC as well as in courts as a litigator or acting as a litigation support in refund cases and assessments.

He is a member of Philippine Institute of Certified Public Accountants (PICPA), Integrated Bar of the Philippines (IBP) Makati Chapter, and Tax Management Association of the Philippines (TMAP).