Nicolás Castillo

Certifications

  • CPA, registered in Florida

Education

  • Master of Science in Taxation, University of Miami
  • B.S.B.A., Accounting and Finance, University of Miami Herbert Business School

Nicolás Castillo

Nicolás Castillo, CPA has spent his 7+ year career to date working in US international tax and the past three years specializing in expat tax for Americans living abroad. During this time, he identified a passion for supporting small and large expat business owners and ambitious expat entrepreneurs who share a common problem: navigating US tax reporting obligations.

As an expat business owner living in Madrid, Nicolás empathizes with the dual issue of US tax reporting complexities and onerous and potentially expensive interactions with the IRS while also complying with local tax law. Expat business owners and entrepreneurs deserve a credible guide through the tax code that too often conflates an honest mistake with intentional failure to follow the rules.

Thus, Rook CPAs was born, a company dedicated to facilitating expat business operations and expat entrepreneurial activity for US expats worldwide, with a focus on Western Europe. Foreigners seeking to pursue business dreams in the US are also welcome aboard Rook CPAs’ ship, as Nicolás’ expertise spans the US expat/US inpat spectrum. With his background in international tax, Nicolás has also helped 100% of American-based companies expand into other countries.

Formerly employed by a large regional accounting firm and most recently a senior tax manager at a multiple award-winning expat tax service provider, Nicolás takes great pride in applying his knowledge of the US tax code in strategically beneficial ways for US expat and inpat business owners. As a first-generation American, Nicolás also understands that, sometimes, we’re called to build and create in a place different than where we’re from. But that shouldn’t be an obstacle to success, which is where Rook CPAs come in.

Recent articles by Nicolás Castillo

Visit our library of educational resources, featuring our latest blog articles, media appearances, and upcoming in-person events.

Moving to Italy from the USA as an American Business Owner

Moving to Italy from the USA as an American Business Owner
The number of Americans moving to Italy from the USA has been on the rise in recent years, with 16,534 officially ...

Tax-Bending Benefits: What Is the Beckham Law in Spain?

Tax-Bending Benefits: What Is the Beckham Law in Spain?
The Beckham Law Spain offers significant tax advantages for qualifying business owners, freelancers, and ...

Moving to Spain from the USA: The 2025 Immigration and Tax Guide

Moving to Spain from the USA: The 2025 Immigration and Tax Guide
Moving to Spain from the USA is becoming an increasingly attractive prospect to many Americans. With interesting ...

Moving to Portugal from USA: Taxes and Practicalities

Moving to Portugal from USA: Taxes and Practicalities
Moving to Portugal from the USA is a decision many Americans are considering these days. Particularly for the ...

A Guide to Applying the Foreign Earned Income Exclusion (FEIE)

A Guide to Applying the Foreign Earned Income Exclusion (FEIE)
Living and working abroad as a US taxpayer comes with exciting opportunities and unique challenges, including ...

How To File US Taxes From Abroad: IRS Form 1040

How To File US Taxes From Abroad: IRS Form 1040
If you're a US taxpayer living abroad, at some point you'll probably need to research "how to file US taxes from ...
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