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Sahel Ahyaie Assar

Sahel Ahyaie Assar


Blockchain and Digital Asset Practice Group Leader

Washington, DC
New York, NY

How Sahel Helps Clients

Sahel is the Leader of Buchanan's Blockchain and Digital Asset Practice Group where she develops, monitors, and assesses the legal needs of clients with respect to all things blockchain, crypto, and digital assets.

Sahel is also an international tax attorney at the firm and has been practicing for more than 20 years in the areas of tax and wealth management.

Sahel is a seasoned international tax lawyer, well-versed in the legal needs and legal issues of relevance to large international families and entrepreneurs in Europe, the Middle East and Asia with U.S. connections. She has extensive experience advising ultra-high-net-worth individuals (UHNWI) and their closely held business interests and real property holdings with respect to international cross-border tax planning (inbound and outbound), international trusts and estates for families of substantial wealth, and compliance with U.S. tax reporting requirements such as assistance with the Foreign Account Tax Compliance Act (FATCA). In addition, Sahel assists individuals with respect to reporting matters before the IRS, including representation in matters pertaining to the IRS Offshore Voluntary Disclosure Program(s) and the IRS Streamlined Filing Compliance Procedures, among others. Sahel is recognized as a thought leader on matters pertaining to taxation of cryptocurrencies.

Foreign financial institutions, fiduciaries and family offices find her years as a practitioner in Zurich, Switzerland to be particularly helpful when it comes to providing them with advice related to U.S. tax reporting, regulatory, banking and ad hoc international cross-border matters. Her practice also focuses on tax planning, structuring and related business advice for a wide range of corporations, LLCs, partnerships, trusts and individuals in both domestic and international tax matters. Sahel counsels foreign individuals with respect to investments in the United States, pre-immigration planning, expatriation, the application of tax treaties, U.S. withholding obligations, offshore tax compliance, residency issues triggering U.S. taxation, and income, transfer tax and reporting obligations of foreigners.

In addition to providing advice to clients with respect to her area of expertise, Sahel often acts as a trusted advisor to a number of wealthy families and as an ambassador to financial institutions, family offices and UHNWI by finding the best resources at Buchanan to assist them with their overall legal needs.

What Clients Can Expect

Clients can expect to find Sahel professional, thorough and dedicated, with a high drive for excellence. The most important aspect of her success is her relentless presence and availability to each of her clients.

I have found that the reason I am hired is because clients trust my knowledge, judgment and the fact that I will be a zealous advocate for them. In addition, my expertise in U.S. federal taxes, fluency in additional languages and experience overseas in Europe and the Middle East provides a unique platform to connect with international families.

Outside the Office

Sahel enjoys tennis, skiing, horseback riding, reading, the arts and culinary endeavors. Had she not become a lawyer, she would have pursued a career as a writer or an art expert in Old Masters.

Proof Points

  • Provide advice to U.S. and foreign individuals and companies with respect to inbound and outbound taxation.
  • Assist with reporting matters pertaining to cryptocurrency (e.g. Bitcoin).
  • Represent foreign financial institutions, family offices and private individuals with all aspects of international tax compliance, including the Foreign Account Tax Compliance Act (FATCA) and the Report of Foreign Bank and Financial Account (FBAR), among others.
  • Represent clients with matters before the Internal Revenue Service in connection with voluntary disclosure and offshore enforcement compliance matters.
  • Provide assistance with international tax and wealth planning for ultra-high net worth individuals and families.
  • Assist foreign lawyers with cross-border matters pertaining to international tax including competent authority and transfer pricing.
  • Named a 2021 Greater Zurich Honorary Ambassador, an award reserved for the area's top influencers in their respective industries.
  • Recognized in the 2023 & 2024 editions of The Best Lawyers in America©  under the Tax Law category.

Prior to joining Buchanan, Sahel was a Senior Wealth Planner with Credit Suisse Group in Zurich, Switzerland, and a Supervising Senior Tax Specialist at KPMG LLP, Washington National Tax in the Mergers & Acquisitions group.

Sahel speaks Farsi and French fluently and German conversationally.