.png)
About TaxKey
Meet Your Tax Experts
We're a team of dedicated tax professionals committed to simplifying complex tax matters and helping you achieve your financial goals.
Two Decades of Tax Excellence
TaxKey was built on a simple belief: everyone deserves access to expert tax advice delivered in plain English. What started as a vision to demystify complex tax regulations has grown into a trusted advisory practice serving hundreds of clients across Ireland.
Today, we continue to uphold our founding principles—combining deep technical expertise with accessible communication and a genuine commitment to our clients' success.
Serving clients across Ireland and internationally
20+ Years
Of trusted tax
advisory experience
Our Mission
Empowering individuals and businesses with clear, practical tax advice that simplifies complexity and unlocks opportunities for financial success.
Clent success is our priority
About TaxKey
Key Milestones
A look back at our growth and achievements over the years
2024
500+ Clients
Continuing to grow and serve clients across Ireland and internationally.
2020
Digital Transformation
Launched fully online services for seamless client experiences.
2010
Team Expansion
Grew our team to better serve our expanding client base.
2004
TaxKey Founded
Started with a vision to make expert tax advice accessible to all.
2015
100+ Clients
Reached a milestone of serving over 100 satisfied clients.
Our Team
Meet the Experts
Qualified professionals dedicated to your financial success
Mairéad Hennessy
Managing Director
With over 20 years of experience in tax advisory, Mairéad founded TaxKey to provide accessible, expert tax guidance to individuals and businesses across Ireland.
CTA AITI, FCA
Mairéad Hennessy
Taxkey was founded by Mairéad Hennessy, as a specialist tax consultancy firm focused on helping clients make confident, commercially sound decisions in complex tax environments.
Mairéad leads a team of expert Chartered Tax Consultants who work with accountants, solicitors and financial planners to deliver practical, proactive tax solutions that protect value and support informed decision-making. The firm is known for its collaborative approach and its ability to bring clarity to high-risk, high-value tax matters.
With over 20 years’ experience as a tax practitioner, Mairéad is recognised for combining technical depth with commercial insight. She regularly speaks at professional conferences on tax technical matters and contributes to leading professional journals.
Mairéad is actively involved in tax policy and administration through her role on the Tax Administration Liaison Committee (TALC), representing the Irish accountancy bodies on key working groups. This front-line exposure to emerging tax issues ensures her advice is current, informed and strategically focused.
Carol Ryan
Senior Chartered Tax Consultant
Carol is a Chartered Tax Advisor with extensive experience supporting high-value and complex client portfolios.
CTA AITI
Carol Ryan
Carol is a Chartered Tax Advisor (CTA AITI) and a qualified accounting technician with over 15 years’ professional experience which she gained during her time with “Top 5” firm and other mid-tier practices.
Carol has extensive experience managing the personal tax, corporation tax, VAT and payroll tax compliance requirements of large, diverse portfolios of clients including High Net Worth individuals and large corporate groups.
Carol has worked with clients across various sectors including hospitality, professional services, property and construction, advising on VAT matters, employment tax matters, share transactions, succession planning and global mobility.
Carol has significant experience dealing with Revenue from voluntary disclosures to full Revenue audits.
Carol is focused on providing solution driven tax advice to clients in a meaningful manner whilst ensuring they feel supported at all times and equipped with the knowledge to understand both their tax obligations and entitlements to the various tax reliefs available.
Tábata Trevisan
Chartered Tax Consultant
Tábata is a Chartered Tax Advisor with over six years’ experience in tax advisory and compliance.
CTA AITI
Tábata Trevisan
Tábata is an Associate of the Irish Tax Institute and a Charter Tax Advisor (CTA AITI) with an Honours degree in Accounting & Finance from Griffith College Dublin. With over six years of practical and technical experience in the field of taxation, Tábata has held roles at both “Big 4” and “Top 10” firms, gaining extensive expertise in various areas of tax advisory and compliance.
Tábata has worked with high net worth individuals and owner-managed businesses on personal and corporate tax affairs. She has also had the opportunity to advise large organizations on matters such as employment tax, workforce restructuring, employer risk identification, management and compliance, Revenue interventions and audits, mergers and acquisitions, share schemes and payroll.
Tábata takes great pride in working with private clients and SMEs, delivering practical tax advice tailored to their unique needs. She is dedicated to providing excellent service and creating real value through her expertise and client-focused approach.
Aidan Toomey
Senior Chartered Tax Consultant
Aidan brings extensive expertise in corporate taxation and cross-border transactions, helping clients navigate complex international tax matters.
CTA AITI, STEP
Aidan Toomey
Aidan holds a Bachelor of Commerce Degree (Honours) from University College Cork and is a Chartered Accountant (ACA) and Chartered Tax Advisor (CTA AITI) with over 10 years’ experience gained working across both practice and industry roles. Aidan is currently undertaking a Diploma in Trust and Estate Planning with the Society of Trust and Estate Practitioners (STEP).
Aidan has extensive experience in the areas of personal income taxation, corporation tax, succession planning, business sale and exit, VAT, employment and mobility tax matters and Revenue interventions and audits and has delivered tax services in the aforementioned areas to a diverse range of private and SME clients.
Aidan is passionate about delivering proactive tax advice to clients, that is tailored to each client’s specific needs and takes great pride in creating real value for his clients through practical tax solutions and ensuring that his clients are always fully supported with the tax knowledge that they require to make timely and relevant decisions.
Excellence
We deliver the highest quality advice, always.
What Drives Us
Our Core Values
Qualified professionals dedicated to your financial success
Integrity
Transparent and ethical in everything we do.
Client Focus
Your success is our measure of success.
Professionalism
Qualified experts you can trust.