About us

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about us

Your time is valuable and better spent managing your
business. Why not leave your annual compliance
and other accounting needs in safe hands?

We’ll happily tailor our approach to suit your requirements. We offer a range of accounting
and tax services for businesses, individuals, trusts and rental property owners and more.

Owner guide
Accounting and Tax Services
Audit and Assurance
Cloud Accounting
Business Advisory Services and Strategy

We’re a firm of Chartered Certified Accountants and Business Advisors based in Auckland with clients in New Zealand and overseas.

We’re determined to remain highly professional and approachable. We are big enough to cover clients’ needs but remain the right size to guarantee we still cover personal attention.  With Business Advisory Services, you are in safe hands.

We have a team with proven skills and experience, and the innovation to help you make good financial decisions to create success, value and prosperity.

Our Value Our Mission Our Vision

We take our “values” very seriously and set ourselves very high standards. In carrying out our obligations to you, work will be delegated to staff with the appropriate levels of skill and knowledge.
This enables us to remain efficient, without compromising our quality to you. However, I accept full responsibility for my team and I will remain the primary contact for you.

Mark Gwilliam FCCA – Director

Our mission is “to deliver consistent and excellent service to our clients; to offer rewarding careers and professional fulfilment for our teams; and to attain financial success so we can grow and prosper”.

We are determined “To be an international professional services company that helps our clients and people succeed in their busy working and personal lives”.


Mark Gwilliam

Director ~ Business Advisory Services and Risk Advisory Services

Mark is the Director in our Auckland office with extensive experience in New Zealand and overseas.


Mark started his career in the UK.  While there, he worked in numerous finances, operations, risk management, internal audit, and credit risk roles throughout the UK and Europe.

He moved to New Zealand in early 2001 and worked at Arthur Andersen and KPMG providing internal audit, governance and risk management services to executive management and boardrooms.

In early 2003, Mark established Business Advisory Accounting & Tax Services Limited.  He spends 25% of his time providing risk and internal audit services to New Zealand’s corporate sector.  The other 75% is spent consulting with owner-managed businesses providing tax advice, preparing financial statements and tax returns, and offering business advice.

Professional Credentials

Mark is a fellow of the Association of Chartered Certified Accountants (ACCA) and holds a Certificate of Public Practice with them.  

Personal Interests

Mark enjoys most types of sports, particularly cricket, football and rugby, albeit only as a spectator these days!  He’s an avid traveller and says he’s accumulated more than a fair share of trials and tribulations along the way.

Contact Mark at markg@bizadvice.co.nz

Mark Gwilliam

(Director and Founder)

40+ Years of Experience

A timeline of our history

Operating in New Zealand and exceeding clients’ expectations for more than seventeen years

We’re extremely proud of our history and heritage as a firm of trustworthy business advisors and chartered accountants. 

From humble beginnings, the firm has grown from strength to strength. It has matured from being a small accounting and tax services practice to one that now helps small business owners, entrepreneurs and executives navigate complex challenges including strategy, risk management and internal audit, managing shared-service centres and operations.


January 2003

Mark establishes Business Advisory Services to provide tax and accounting services.

June 2007

We begin providing our new risk          advisory and assurance services                 to NZX listed organisations.

August 2012

We secure our first major risk         management and internal                             audit services contract                 with the health sector.

January 2014

We begin using Xero accounting           software for the first time

March 2017

Mark Gwilliam, FCCA CA, becomes a member of the Chartered Accountants Australia and New Zealand.

January 2018

Business Advisory Accounting & Tax Services Limited celebrate fifteen years as Auckland chartered accountants.

August 2019

We revise our eBook and publish “Tax Saving Strategies for Small-Business Entrepreneurs” and continue to offer it free of charge.

May 2001

Mark Gwilliam, FCCA, moves to                      New Zealand from the UK.

October 2004

Business Advisory Accounting & Tax Services Limited is formed.

August 2009

We launch our virtual Financial          Controller services to small to               medium sized businesses.

January 2013

Business Advisory Accounting & Tax Services Limited celebrate ten years as Auckland chartered accountants.

June 2016

Our global professional body, the Association of Chartered Certified Accountants (ACCA) announces a strategic alliance with the Chartered Accountants Australia and New Zealand (CAANZ).

October 2017

We publish and offer our first edition of our eBook, “Tax Saving Tips”, free of charge.

September 2018

We extend our business advisory services and launch our virtual CFO services to small to medium sized businesses.

March 2020

We begin to offer fixed monthly          accounting fees for all of our                  annual tax compliance services.

Our clients are at the core of everything we do.

Have a question or comment?


Please contact us with your enquiry. We will provide you with a personal response within one business day.