Practical guides: forms, days, home and remote work

Short guides for individuals, written from official sources (IRS, OECD, EU law). Each one says what the rule is, what people often get wrong and when to see a professional.

• Form W-8BEN: what it is and how to fill it in
  Who gives Form W-8BEN, what it does, the lines that matter for individuals, the treaty claim, the 3-year validity and the 30-day rule on changes.
• CRS self-certification: why your bank asks for your tax residence
  What the Common Reporting Standard is, what a self-certification must contain, residence in two countries, no tax number, changes and what is reported.
• How to count 183 days
  The 183-day rule for salaries in tax treaties: which days count, the 12-month window, days that do not, and how domestic residence rules differ.
• Permanent home in a tax treaty
  What counts as a permanent home under Article 4(2) of tax treaties: rented or owned, available at all times, what does not count, the order of tests.
• Centre of vital interests and habitual abode
  How treaties decide residence with a home in both countries: personal and economic ties, then habitual abode — frequency, duration, regularity.
• Working remotely for a foreign employer
  Working from home for a foreign employer: where salary is taxed, permanent establishment risk under the 2025 OECD Commentary, EU social security.

Sources checked: 10/11/2026. General information, not legal advice. Treaties and national laws can differ from the OECD Model; always check the treaty that applies to you.