Partners in Your Success

Our team is unusual in the accounting world because we actually work together for each client. At most firms, each accountant has his or her own clients; it’s a silo approach that denies the client access to the unique skills and specialized knowledge that others in the firm might be able to offer.

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That’s not us. We believe that you deserve the best service around, and if one member of our team is better qualified to advise you in a specific area, you should have full access to that person. We partner with you, as a team, to help you build a successful business and an enjoyable life.

Clayton E. Achen CPA, CA, TEP

Clayton E. Achen

Clayton is the visionary driving force behind Achen Henderson, the partner who looks into the future, sees what he wants to create, and brings everyone along on the adventure. His dream is twofold: to be at the forefront of the evolution of the accounting industry and enjoy his life while helping our clients enjoy building their businesses.

Clayton is the visionary driving force behind Achen Henderson.

Clayton is our Canadian tax expert and has a background in tax compliance, planning, and strategy. He has worked with a wide variety of clients ranging from owner-managed small businesses to publicly traded oil and gas companies. He specializes in the taxation of private companies, transactions, and high-net-worth families. Clayton has served on several Boards of Directors including Music Seeds International, and currently sits on the board of the Elder Statesmen Group.

After a decade of retail management, Clayton obtained his Bachelor of Management from the University of Lethbridge in Alberta. He returned to Calgary where he articled for a mid-market multinational accounting firm then worked for several years in the tax group at another Big-4 accounting firm. Clayton is a Chartered Professional Accountant (CPA), qualifying as a Chartered Accountant (CA), and holds the Trust and Estate Practitioner (TEP) designation.

Clayton has completed Parts I and II of CPA Canada’s In-depth Tax course and advanced studies in owner-manager taxation, as well as the Canadian Petroleum Tax Society’s Taxation of Canadian Oil and Gas Companies courses. He is also a member of the Society of Trust and Estate Practitioners and a member of the Canadian Tax Foundation. In 2019, Clayton was invited to testify to the Standing Committee on Finance in Parliament where he advocated for Canadian Private Companies.

George Henderson CPA, CA

George Henderson

Nothing fazes George and his calm, logical, laid-back energy is the perfect counterpoint to Clayton’s drive and determination. Detail-oriented, he finds peace in the present moment, finding meaning in whatever task is in front of him.

George is focused on building lasting relationships and delivering excellent client service.

George is our accounting and controls expert with a background in accounting and financial reporting. He worked for many years in the private company groups of several large mid-market accounting firms and has also worked as a controller for a publicly traded oil and gas service company.

George completed his Bachelor of Management at the University of Lethbridge in Alberta. He then articled at a national accounting firm in Red Deer, Alberta, before returning to Calgary where he worked his way up the ranks of a multinational accounting firm in their private enterprise group. Most recently, George worked as a controller for a publicly traded oil and gas services company. He is a Chartered Professional Accountant (CPA), qualifying as a Chartered Accountant (CA).

George has extensive experience in financial reporting, financial statement preparation and taxation of private companies. He is focused on building lasting relationships and delivering excellent client service.

Carol Sadler CPA, CA, CPA (Illinois, U.S.), TEP

Carol Sadler

A people person, Carol relishes spending time with others, be it clients, colleagues, family, or friends. She values integrity and collaboration and enjoys meeting with clients to give them the information they need to build excellent businesses. A technical expert in U.S. and Canadian tax, she’s a valuable resource for U.S. clients doing business in Canada, Canadian clients doing business in the U.S., and individuals who have to file in both Canada and the U.S.

Carol values integrity and collaboration with clients to build excellent businesses.

Carol draws on an extensive background in Canadian, U.S., and cross-border tax compliance, planning, and strategy. She works with private companies and high-net-worth families in various industries, ranging from the oil and gas and resource sector to real estate and consulting.

Carol earned her Bachelor of Commerce with distinction from the University of Alberta. She then spent several years working in the tax group of a Big-4 accounting firm where she began to provide U.S. and Canadian tax services. Carol then established her own tax firm, Sadler Tax Advisors, which she developed into a respected Calgary area tax firm before joining Achen Henderson LLP as head of U.S. and cross-border taxation. She is a Chartered Professional Accountant (CPA), qualifying as a Chartered Accountant (CA), and a Certified Public Accountant (Illinois, U.S.). Carol also holds the Trust and Estate Practitioner (TEP) designation.

Carol has completed Parts I, II, and III of CPA Canada’s In-depth Tax course and advanced studies in wealth preservation. She is a member of the Society of Trust & Estate Practitioners, the Canadian Tax Foundation, and the American Institute of Certified Professional Accountants (Tax Section). In 2018, Carol received the Chartered Professional Accountant Distinguished Service Award for her years of service to the profession and the public.

Wallace O’Neil CPA, CA

Wallace O’Neil

The son of a high school math teacher, Wallace’s fascination with numbers and problem-solving started at an early age and he continues to draw on it to help clients succeed. A manager at Achen Henderson, he’s involved with almost all our clients at some point, always communicating in a timely, professional manner and quickly getting them the answers they need.

Wallace values an individualized approach to serving clients.

Wallace’s background is in tax compliance and financial reporting. As a manager in the private company group at a national mid-market accounting firm, he worked closely with a variety of professional corporations and oil and gas service firms, as well as companies in financial services and real estate. In 2019, Wallace completed CPA Canada’s In-depth Tax Program.

Wallace completed his Bachelor of Accounting at Mount Royal University in Calgary. He joined a national accounting firm where, as a manager in its private company group, he focused on assurance and tax for private companies and their owners, giving him extensive knowledge to help our entrepreneurial clients.

A Chartered Professional Accountant (CPA) who qualified as a Chartered Accountant (CA), Wallace appreciates Achen Henderson’s individualized approach to serving clients as he can focus on each client’s specific needs to identify the solutions that will help them achieve their goals. In 2019, Wallace completed all levels of CPA Canada’s In-depth tax program.

Roni Kirkness CCAP, B.Mgt.

Roni Kirkness

Roni leads our Managed Financial Services (MFS) practice, which helps our clients transition from ‘old-school’ bookkeeping systems to modern, real-time, scalable accounting systems. Roni works with business owners to ensure that they have the information that they need, right when they need it, to make more informed business decisions. She helps business owners transition to cloud-based applications, integrating automated bookkeeping and payroll, and leadership services to ensure our client’s growth and opportunity.

Roni's main focus is our client's positive experience with us.

In 2020, Roni earned her Bachelor of Management from the University of Lethbridge majoring in Human Resource Management and Labour Relations. She is currently a member of the Certified Human Resources Professional (CPHR) and is working towards her designation. 


With her combined education and her membership to CPHR provides a unique skill set that is valuable for our internal HR policies and practices along with the ability to provide HR support to our clients.

Roni spent a decade leading administrative teams at a Big-4 accounting firm. She focused on the development and implementation of digital information processes and workflows for the firm. Roni is a Canadian Certified Administrative Professional (CCAP), which has provided support in having efficient and productive administrative procedures. Prior to accounting and finance, she has worked in industries including architectural and engineering, surgical facilities, new home construction, and hospitality industries.

Barb MacDonald

Barb MacDonald

Barb is a real pro when it comes to bookkeeping, she’s been doing it for  nearly 20 years! She has dealt with a very diverse range of clients, helping them to get their books on track and keep them that way. Barb focuses on using the latest in modern bookkeeping technology to ensure a high degree of accuracy and customer satisfaction.

Barb is the gatekeeper to clean books and useful financial informattion.

Barb has an Accounting Diploma from Kwantlen University in Surrey, B.C., Barb has worked independently running her own bookkeeping practice, as well as for several private and non-profit business, serving a variety of accounting roles. As a previous independent business owner, Barb knows the challenges that face businesses on a regular basis and brings a wealth of experience and understanding of the rigours of maintaining books with the highest level of compliance and quality. 

On the weekends, you will find Barb camping, hiking, fishing and enjoying plenty of time with family and friends. 

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