Our team


U.S. Tax Consultant

+41 58 300 6060

Matthew has worked in U.S. tax compliance for over 15 years. He is a member of various tax planning organizations.

Since 2004, Matthew has handled hundreds of IRS tax controversy matters. He has been advising cross-border individuals and families with U.S. tax issues. Matthew specializes in finding tax efficient solutions for his international clients.

Matthew is also fluent in French and has a valuable knowledge of the French and Swiss tax systems.

Tim Lebrun

Tax Partner

+41 58 300 6063

Timothy is a U.S. Certified Public Accountant (CPA) with 19 years of experience in taxation, accounting, and financial services operations. He specializes in assisting private equity funds, hedge funds, family offices, high net worth individuals and other private investors with U.S. domestic and international taxation, tax due diligence and structuring, tax compliance, tax provisions and FATCA-related issues, as well as fund and special purpose vehicle operations.

Prior to working at ATAS, Timothy worked for 6 years in Switzerland managing U.S. tax operations for one of Europe’s largest private equity firms, was Tax Director of a Fund Service Group for 7 years at a midsize public accounting / fund administration firm in Miami, and worked for 6 years at a Big 4 accounting firm within their Financial Services Group in Florida and New York. He holds a Master’s Degree in Taxation and a Bachelor’s Degree in Accounting from Long Island University.


Senior Tax Consultant

+41 58 300 6065

Sameera is an experienced UK and international tax accountant, a member of The Society of Trusts and Estate Practitioners (STEP) and a recipient of a Masters in Taxation from the University of London, Institute of Advanced Legal Studies in 2012.

Sameera specializes in international tax and accounting issues, with a particular focus on advising private client law firms, HNWIs, offshore trustees and UK trust beneficiaries on matters relating to UK residency, investment and property portfolios, taxation of offshore trusts in UK, voluntary disclosures to HMRC and annual UK tax filings.

Sameera is from Tanzania where she qualified as an accountant in 2001 before relocating to the UK and working as an in-house accountant for a multi-national conglomerate until 2012. Since then, she has been working as an independent international tax advisor based in London. Sameera joined ATAS as a consultant in January 2018 to further diversify our international tax expertise.

Sameera is fluent in several languages, written and spoken, including English, Kutchi, Gujarati, Hindi, Kiswahili and Urdu. For the past 6 years, Sameera has developed strong client relationships assisting many private clients on the technical details of their tax obligations.


Senior Tax Consultant

+41 58 300 6060

Siresha is an IRS enrolled agent (EA) with 12 years of experience in taxation. She earned her Master of Business Administration (MBA) in Finance and Marketing and Bachelor of Commerce degrees from India.

She specializes in international taxation and has significant experience in preparation and review of individual, corporate, partnership and high net worth individual tax returns. Siresha also has extensive experience in FBAR, FATCA, OVDP and PFIC.

Prior to working at ATAS, Siresha worked for 10 years in various Big 4 accounting firms in India and USA, where she handled inbound and expatriate tax related projects for various fortune 500 companies.


Account Relationship Coordinator

+41 58 300 6069

Sarah-Jane acts as a liaison between our clients and our team members to ensure the delivery of U.S. individual tax returns, trusts and other tax related information. She is a valued member of the team. Enthusiastic and personable, she consistently ensures high-quality service to each of our local and international clients.

Sarah-Jane has a broad range of experience in client services and financial fields. She completed her Service Management and Engineering Master’s Degree in 2016 at the University of Applied Sciences and Arts Western Switzerland (HES-SO Master) in Lausanne, which has expanded upon her strong experience in providing excellent levels of customer service. As a highly motivated and proactive person, Sarah-Jane possesses a keen attention to detail combined with a team-minded and problem-solving approach. She speaks fluent French and English and basic German.



+41 58 300 6060

Chloe is a British economics graduate who studied in the U.K. Her areas of expertise within academic studies and professional experiences are accounting, taxation and mathematics. Since 2015 has been involved with international tax compliance, U.S. regularization matters and U.S. coordination.


Documents Coordinator

+41 58 300 6060

Within U.S. legal teams in Switzerland, Henrieta brings a balanced set of organizational skills to our company. She has the ability to directly deal with people at all levels and from different backgrounds. She is fluent in several languages, written and spoken. Her mother tongue is Slovakian; she is professionally proficient in English, German and Czech and also understands Polish and Russian.