About Us
Welcome to Optimise Accountants, your trusted partner for international tax advice and support. Founded in 2003 by Simon Misiewicz, a UK-qualified accountant (ACCA), UK tax advisor (ATT), and American tax advisor (Enrolled Agent), we have been at the forefront of providing expert tax guidance to individuals and businesses navigating the complexities of cross-border taxation. With over a decade of specialised experience in international tax advice since 2013, we are uniquely positioned to help clients understand their tax obligations and opportunities wherever they are.
Our Mission
At Optimise Accountants, our mission is simple: to provide clear, effective, and personalised tax solutions for individuals and businesses facing the challenges of international relocation. Whether you’re an American moving abroad or a UK citizen seeking opportunities overseas, we are here to ensure your transition is as tax-efficient as possible. By understanding and utilising international tax treaties, we aim to help our clients minimise their tax liabilities and avoid costly mistakes.
Expertise in US Tax for Americans Abroad
For Americans moving to the UK, Spain, Canada, or any other country, our expertise ensures you remain compliant with US and foreign tax laws. As an American, even when living abroad, you are required to file a 1040 tax return to the Internal Revenue Service (IRS). Our team provides in-depth advice on managing your ongoing tax obligations, such as filing for foreign-earned income exclusions, claiming foreign tax credits, and understanding the complex rules around dual tax residency.
Beyond compliance, we also help Americans minimise their income tax, capital gains tax, and estate tax liabilities when moving to a new country. Understanding how your international income, investments, and assets are taxed in the US and your new home country is critical to avoiding double taxation. With the right guidance, we help our clients navigate tax complexities efficiently and effectively.
Supporting British Citizens Moving Abroad
We also provide specialised tax advice to British citizens moving to the US, Canada, Spain, or elsewhere. Many people don’t realise that even after leaving the UK, there may still be a requirement to file a UK self-assessment tax return with HMRC. This is particularly important if you have income-generating assets such as property, investments, or businesses operating in the UK.
Our team helps UK expatriates understand what to do with their homes, investments, and businesses when relocating. Moving money or selling assets after you’ve moved to a new country can have significant tax consequences. Without proper advice, there’s a real risk of paying tax twice. We are experts in interpreting Double Taxation Agreements (DTAs) and helping our clients make smart decisions to avoid this pitfall.
Comprehensive Advice on Investments, Homes, and Businesses
Relocating internationally is a significant financial decision, and the tax implications can be overwhelming. When moving countries, we aim to provide our clients with the best possible advice on managing their wealth, homes, investments, and businesses. Selling a home, cashing out investments, or moving business operations can trigger complex tax rules. We help our clients make informed decisions so they don’t fall into tax traps or face unexpected liabilities.
