Australia

“Providing good service to clients is not just about ATO tax compliance, it’s about understanding their unique needs and delivering tailored solutions.”

Mia Henner-Cwirn

Principal, Business Advisory

Mia Henner-Cwirn is a highly accomplished Chartered Accountant with over 25 years of experience in tax and accounting. Renowned for her technical expertise and commercial acumen, Mia has a strong track record supporting large commercial groups in meeting complex tax compliance requirements with confidence and precision.

Throughout her career, Mia has partnered with both Australian and international organisations, including Significant Global Entities, to navigate increasingly complex tax environments and regulatory frameworks. She has played a key role in guiding clients through Australian compliance lodgements, and leading proactive restructuring initiatives designed to enhance efficiency and long-term value.

Mia’s extensive experience spans international subsidiaries, professional services firms, hospitality groups, and trading businesses, enabling her to build deep industry insight and foster enduring client relationships built on trust and results.

In her role at William Buck, Mia leads and mentors a high-performing team, driving the delivery of proactive business strategies and ensuring seamless coordination across all aspects of client engagements. She works closely with internal accounting teams, providing clear, strategic guidance and maintaining strong alignment with client objectives.

Known for her collaborative approach and exceptional communication skills, Mia establishes strong rapport with clients, stakeholders, and colleagues alike. She thrives in complex environments and is committed to identifying and implementing optimal solutions.

The Facts:

Core Expertise

  • International subsidiaries and cross-border tax matters
  • Monthly management reporting and ATO compliance
  • Payroll and state payroll tax compliance

Qualifications & Associations

  • Bachelor of Commerce (Accounting)
  • Member, Chartered Accountants Australia and New Zealand (CA)

Industries & Specialisations

  • Large multinational groups and Significant Global Entities
  • Cost-plus subsidiary structures
  • Medium-sized Australian privately owned corporate groups
  • Recruitment, technology, and large private businesses within hospitality and trading sectors

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